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SARS-CoV-2 infection often causes neurological disorders. Experimental studies on an animal model have shown that SARS-CoV-2 is able to cross the blood-brain barrier. Researchers have also discovered that SARS-CoV-2 can infect glial cells. Gliomas are the most common type of brain tumor. Oncological patients are at high risk of infections, including SARS-CoV-2. Moreover, their weakened immunity causes the level of antibodies after infection or vaccination to be lower than in the healthy population. Therefore, the aim of our study was to evaluate the occurrence of SARS-CoV-2 RNA in tumor tissue collected during surgery. We also tested the level of anti-SARS-CoV-2 antibodies in these patients. The obtained results indicate the tropism of the virus to tumor tissue – glioblastoma. The level of anti-SARS antibodies was higher in patients with SARS-CoV-2 RNA detected in tumour tissue. [ABSTRACT FROM AUTHOR]

Using a modified proximity extension assay, total and immunoglobulin (Ig) class-specific anti-SARS-CoV-2 antibodies were sensitively and conveniently detected directly from ø1.2 mm discs cut from dried blood and saliva spots (DBS and DSS) without the need for elution. For total Ig detection, antigen probes were prepared by conjugating recombinant spike protein subunit 1 (S1-RBD) to a pair of oligonucleotides. To detect isotype-specific antibody reactivity, one antigen probe was replaced with oligonucleotide-conjugated antibodies specific for antibody isotypes. Binding of pairs of oligonucleotide-conjugated probes to antibodies in patient samples brings oligonucleotides in proximity. An added DNA polymerase uses a transient hybridization between the oligonucleotides to prime synthesis of a DNA strand, which serves as a DNA amplicon that is quantified by real-time PCR. The S1-RBD-specific IgG, IgM, and IgA antibodies in DBS samples collected over the course of a first and second vaccination exhibited kinetics consistent with previous reports. Both DBS and DSS collected from 42 individuals in the autumn of 2023 showed significant level of total S1-RBD antibodies with a correlation of R = 0.70. However, levels in DSS were generally 10 to 100-fold lower than in DBS. Anti-S1-RBD IgG and IgA in DSS demonstrated a correlation of R = 0.6. [ABSTRACT FROM AUTHOR]

A 67-year-old woman with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis was not vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was on multiple immunosuppressive drugs. She was hospitalized because of interstitial shadowing in the lungs and diagnosed with persistent coronavirus disease 2019 (COVID-19). Despite treatment with a recombinant monoclonal antibody and antivirals, her symptoms persisted and she lacked a specific antibody response. She tested negative for SARS-CoV-2 antigen after the second antiviral treatment, and a subsequent chest radiograph showed improvement. However, the antibody levels did not change. This case highlights the importance of careful monitoring of the SARS-CoV-2 antigen and antibody levels during COVID-19 treatment in patients with immunosuppression. [ABSTRACT FROM AUTHOR]

ABSTRACT Monitoring antibody prevalence is a valuable tool to evaluate the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a community, identify risk factors, and assess the impact of clinical and public health intervention strategies. The antibody prevalence of SARS-CoV-2 in children in the United States in early 2022 was estimated by the Centers for Disease Control and Prevention to be 74.2%, using seroprevalence from a variety of sources. A study by the New Jersey Department of Health in late 2022/early 2023 in unvaccinated children found a lower prevalence, 68% when using a gum swab method to detect antibodies. This study compared the accuracy of the gum swab method to detect antibodies with simultaneously obtained serological samples in additional children. This cross-sectional study recruited well children, not vaccinated for SARS-CoV-2, aged 18 months to 11 years, who were scheduled for routine bloodwork at an inner-city university-based pediatric clinic. With parental consent, an extra 5 cc of blood and a gum swab sample were collected. Results from Diabetomics CovAb SARS-CoV-2 gum swab antibody test and Rutgers New Jersey Medical School enzyme-linked immunosorbent assay serology test for spike protein antibody were compared. The seropositivity of these paired samples was compared using McNemar’s test, Cohen’s kappa statistic, and other diagnostic accuracy statistics. From June through August 2023, 86 children were recruited. Antibody positivity by gum swab was 70.9% and by serology was 87.2%. The Cohen’s kappa statistic was 0.39 indicating minimal agreement and McNemar’s test was significant (P-value of 0.0010). Compared with serology, gum swab was 78.7% sensitive (95% CI 68.7% to 87.3%) and 81.8% specific (95% CI 48.2% to 97.7%). Positive and negative predictive values were 97.5% and 29.9%, respectively, and accuracy was 79.0%. Sensitivity in non-Hispanic versus Hispanic children was 74.2% versus 82.5%, and in children 6–11 years versus 18 months to 5 years, it was 74.2% versus 81.8%. While the gum swab method of antibody detection is not as sensitive or specific as serology, sample collection can be done in settings where phlebotomy is not feasible. This method could be useful in non-clinical settings such as surveillance, for assessing epidemiological trends and associations.IMPORTANCERecently a study determining the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in unvaccinated children in NJ (Katic et al. 2023. Pediatric Academic Societies Meeting; Washington, D.C. https://2023.pas-meeting.org/searchbyposterbucket.asp?bm=Public+Health+%26+Prevention&t=Public+Health+%26+Prevention&pfp=Track) was conducted using a gum swab method for antibody detection. The Diabetomics CovAB test, which qualitatively identifies antibodies to SARS-CoV-2 spike protein, is a point-of-care, low-cost test, that is easy to administer in children. While this test provides sensitive and specific results in adults [US Food and Drug Administration (FDA). 2022. Center for devices and radiological health. EUA authorized serology test performance. Available from: https://www.fda.gov/medical-devices/covid-19-emergency-use-authorizations-medical-devices/eua-authorized-serology-test-performance], data on its accuracy in children is lacking. As a follow-up to the above-mentioned study, we compared the results of the gum swab test to a serologic antibody test. We found that the gum swab test was inferior to serology but was fairly sensitive and specific with a high positive predictive value. While the test is not ideal for diagnostic purposes in children it can be a valuable tool for public health officials and pediatricians to understand the extent of past health interventions.

Key Clinical Message: Most Japanese patients naturally infected with COVID‐19 were infected after mRNA vaccination, and many maintained high antibody titers due to hybrid immunity. The significance of additional vaccination in hybrid‐immunized cases is highly questionable. Spontaneous infection with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) after mRNA vaccination causes a marked increase in antibody titer because of the combined effect of vaccine and infection ("hybrid immunity"). In this study, we discuss the significance of the mRNA vaccine booster inoculation that has been repeatedly performed in Japan. We describe the temporal trends of antibody titers in cases in which antibody titers were markedly increased by hybrid immunization. The antibody titer increased with hybrid immunization and tended to decrease with time. However, several cases maintained high antibody titers for approximately 1 year after coronavirus disease 2019 (COVID‐19) diagnosis, even without booster vaccination. Most Japanese patients naturally infected with COVID‐19 were infected after mRNA vaccination, and many maintained high antibody titers due to hybrid immunity. The significance of additional vaccination in hybrid‐immunized cases is highly questionable regarding cost‐effectiveness and risk–benefit. [ABSTRACT FROM AUTHOR]

Background Improved coronavirus disease 2019 (COVID-19) prevention is needed for immunocompromised individuals. Methods A prospective study was performed of health care workers (HCW) and immunocompromised participants with baseline serology following 2 mRNA vaccine doses and who were retested after dose 3 (D3); multivariable regression was used to identify predictors of serological responses. IFN-γ/TNF-α T-cell responses were assessed in a subset. Results In total, 536 participants were included: 492 immunocompromised (206 solid organ transplant [SOT], 128 autoimmune, 80 hematologic malignancy [HM], 48 solid tumor, 25 HIV), and 44 HCW. D3 significantly increased spike IgG levels among all, but SOT and HM participants had the lowest median antibody levels post-D3 (increase from 0.09 to 0.83 and 0.27 to 1.92, respectively), versus HCW and persons with HIV, autoimmune conditions, and solid tumors (increases from 4.44 to 19.79, 2.9 to 15.75, 3.82 to 16.32, and 4.1 to 25.54, respectively). Seropositivity post-D3 was lowest for SOT (49.0%) and HM (57.8%), versus others (>90%). Neutralization post-D3 was lowest among SOT and HM. Predictors of lower antibody levels included low baseline levels and shorter intervals between vaccines. T-cell responses against spike increased significantly among HCW and nonsignificantly among immunocompromised individuals. Conclusions D3 significantly improves serological but not T-cell responses among immunocompromised individuals. SOT and HM patients have suboptimal responses to D3. [ABSTRACT FROM AUTHOR]

Introduction: Inflammatory bowel disease (IBD) patients use a wide variety of immunosuppressive drugs, including biologics, but their effect on SARS-CoV-2 vaccine antibody levels remains a mystery. Aim: We analysed whether the drugs used in the treatment of IBD patients could affect the concentration of SARS-CoV-2 antibodies. Material and methods: This is a prospective, single-centre evaluation of the persistence of SARS-CoV-2 antibodies after vaccination at various time points: every 2 months throughout the 6th month after the first dose. Results: We included a total of 346 vaccinated IBD patients in the study. A negative correlation between antibody level and time from full vaccination was confirmed for the following types of therapy: infliximab (rho = -0.32, p < 0.001), adalimumab (rho = -0.35, p = 0.025), and vedolizumab (rho = -0.50, p < 0.001). In the case of other, long-term drug administration, a negative correlation between antibody level and time from full vaccination was confirmed for mesalazine (rho = -0.35, p < 0.001), budesonide (rho = -0.58, p = 0.004), systemic glucocorticoids (rho = -0.58, p < 0.001), and azathioprine (rho = -0.44, p < 0.001). Conclusions: Due to the immunosuppressive and biological treatment, IBD patients are exposed to a shorter persistence of SARS-CoV-2 antibodies and require booster doses. The role of gastroenterologists in educating patients about the need to continue SARS-CoV-2 vaccination remains crucial. [ABSTRACT FROM AUTHOR]

Key Clinical Message Most Japanese patients naturally infected with COVID‐19 were infected after mRNA vaccination, and many maintained high antibody titers due to hybrid immunity. The significance of additional vaccination in hybrid‐immunized cases is highly questionable. Abstract Spontaneous infection with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) after mRNA vaccination causes a marked increase in antibody titer because of the combined effect of vaccine and infection (“hybrid immunity”). In this study, we discuss the significance of the mRNA vaccine booster inoculation that has been repeatedly performed in Japan. We describe the temporal trends of antibody titers in cases in which antibody titers were markedly increased by hybrid immunization. The antibody titer increased with hybrid immunization and tended to decrease with time. However, several cases maintained high antibody titers for approximately 1 year after coronavirus disease 2019 (COVID‐19) diagnosis, even without booster vaccination. Most Japanese patients naturally infected with COVID‐19 were infected after mRNA vaccination, and many maintained high antibody titers due to hybrid immunity. The significance of additional vaccination in hybrid‐immunized cases is highly questionable regarding cost‐effectiveness and risk–benefit.

Type 2 diabetes mellitus (T2DM) remains an important public health problem in both developing and developed countries. In addition, the recent COVID-19 pandemic has revealed furthel risks for diabetes patients in terms of symptoms and disease progression. Higher mortality and morbidity are related to the complexity of the pathology of this chronic underlying disease, which negatively affects the immune response to the SARSCoV-2 virus. The humoral response plays an important role in the eradication of the virus; thus, it was analyzed in vaccinated diabetics who underwent COVID-19, as well as in the control group. The aim of this study was to assess the prevalence and level of IgG antibodies raised against the nucleocapsid protein (NCP), S1 subunit receptor binding domain (RBD) and subunit Spike 2 (S2) subunit of the virus’s S protein using the Microblot Array test. The results demonstrated significantly lower prevalence and titers of anti-SARS antibodies in diabetic patients compared to the control group. In addition, antibody titers were negatively related to the duration of this chronic disease, body mass index (BMI), comorbidities and HbA1c concentration. Further research is needed to develop the best strategy for specific prevention of SARS-CoV-2 infection in diabetic patients.

PurposeWe describe the design of a longitudinal cohort study to determine SARS-CoV-2 incidence and prevalence among a population-based sample of adults living in six San Francisco Bay Area counties.MethodsUsing an address-based sample, we stratified households by county and by census-tract risk. Risk strata were determined by using regression models to predict infections by geographic area using census-level sociodemographic and health characteristics. We disproportionately sampled high and medium risk strata, which had smaller population sizes, to improve precision of estimates, and calculated a desired sample size of 3400. Participants were primarily recruited by mail and were followed monthly with PCR testing of nasopharyngeal swabs, testing of venous blood samples for antibodies to SARS-CoV-2 spike and nucleocapsid antigens, and testing of the presence of neutralizing antibodies, with completion of questionnaires about socio-demographics and behavior. Estimates of incidence and prevalence will be weighted by county, risk strata and sociodemographic characteristics of non-responders, and will take into account laboratory test performance.ResultsWe enrolled 3842 adults from August to December 2020, and completed follow-up March 31, 2021. We reached target sample sizes within most strata.ConclusionsOur stratified random sampling design will allow us to recruit a robust general population cohort of adults to determine the incidence of SARS-CoV-2 infection. Identifying risk strata was unique to the design and will help ensure precise estimates, and high-performance testing for presence of virus and antibodies will enable accurate ascertainment of infections.

The emergence of the SARS-CoV-2 Omicron variant has raised concerns due to its increased transmissibility and potential implications on clinical characteristics and outcomes in infected individuals. The aims of this report were to study the profile of SARS-CoV-2 infection with omicron variant, investigate the infection outcome, reinfection rates with associated factors, antibody levels, and explore the associations between biochemical markers and disease severity. This prospective cohort study was conducted in Duhok city in the Northern of Iraq. All volunteers with confirmed SARS-CoV-2 RT–PCR and confirmed Omicron infection who were older than 18 years old and agreed to participate were recruited for this study. The study was carried out from January to April 2022. There were 234 cases of confirmed SARS-CoV-2 RT–PCR Omicron infection. The mean age was 48.12±17.3 years, 43.2% were vaccinated, and 40.2% were male. Among the recruited patients, 99.1% recovered and did not need hospitalization. In this study, (38.9%) had a history of previously confirmed COVID-19 infection. Reinfection was significantly higher in females than males (p=0.04; OR= 0.56). It was found that the IgG antibody levels were higher in patients who received Pfizer-BioNTech than in those who received other vaccines (p=0.001). The levels of IgG were also significantly higher in patients with mild infection (p=0.046), whereas the levels of D-dimer were significantly higher in patients with severe cases of the infection compared to those with mild or moderate cases (p=0.001). Additionally, the levels of C-reactive protein (CRP) were observed to be higher in individuals with moderate cases of infection than in mild and severe cases (0.001). Individuals who contracted the Omicron strain generally had positive outcomes. Reinfection with the Omicron variant was relatively high. IgG levels were higher in patients with mild disease, implying that they were associated with decreased disease severity. We found significant associations between D-dimer levels and the severity of the disease. Additional research is required to investigate the long-term effects of Omicron infection.

Background Characterization of longitudinal SARS-CoV-2-specific antibody responses in children following infection and vaccination is needed to inform SARS-CoV-2 vaccine policy decisions for children, which may differ from adults. Methods We enrolled individuals at the time of SARS-CoV-2 infection or vaccination for longitudinal serological testing and compared SARS-CoV-2-spike-specific IgG and neutralization activity in children and adults stratified by infection and vaccination status using enzyme-linked immunosorbent and virus neutralization assays. Results Between June 2020 and December 2022, we collected sera from 669 participants aged 40 days to 55 years, including 330 unvaccinated individuals with laboratory-confirmed SARS-CoV-2 infection, 180 vaccinated SARS-CoV-2-naïve individuals, and 159 vaccinated previously infected individuals. Half (n = 330, 49.3%) were children. SARS-CoV-2-specific IgG and neutralization activity in children < 12 years old in response to infection persisted at higher levels than those of adults through at least 6 months (spike-specific IgG levels, 2.05 [95% CI: 1.4-3.1] times higher than adults; neutralizing activity, median 88.8 vs 75.2%, respectively, p  = .04). In addition, all pediatric participants had significantly higher IgG levels compared with adults at 6 months following infection or vaccination, regardless of prior infection status. Vaccine-induced SARS-CoV-2-specific IgG responses in previously infected individuals persisted at higher levels than those from infection alone at 6 months (median AUC, children 5-11 years old, 9115 vs 368; adolescents 3613 vs 475; adults 1956 vs 263, all p  < .001). Conclusions These data demonstrate the robust and persistent immunologic response of SARS-CoV-2 vaccination in children and emphasize the benefit of vaccination after SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

Background: Quantification of the SARS-CoV-2-specific immune response by serological immunoassays is critical for the management of the COVID-19 pandemic. In particular, neutralizing antibody titers to the viral spike (S) protein have been proposed as a correlate of protection (CoP). The WHO established the First International Standard (WHO IS) for anti-SARS-CoV-2 immunoglobulin (Ig) (NIBSC 20/136) to harmonize binding assays with the same antigen specificity by assigning the same unitage in binding antibody units (BAU)/ml. Method: In this study, we analyzed the S1-specific antibody response in a cohort of healthcare workers in Germany (n = 76) during a three-dose vaccination course over 8.5 months. Subjects received either heterologous or homologous prime-boost vaccination with ChAdOx1 nCoV-19 (AstraZeneca) and BNT162b2 (Pfizer-BioNTech) or three doses of BNT162b2. Antibodies were quantified using three anti-S1 binding assays (ELISA, ECLIA, and PETIA) harmonized to the WHO IS. Serum levels of neutralizing antibodies were determined using a surrogate virus neutralization test (sVNT). Binding assays were compared using Spearman's rank correlation and Passing-Bablok regression. Findings: All assays showed good correlation and similar antibody kinetics correlating with neutralizing potential. However, the assays show large proportional differences in BAU/ml. ECLIA and PETIA, which detect total antibodies against the receptor-binding domain (RBD) within the S1 subunit, interact similarly with the convalescent plasma-derived WHO IS but differently with vaccine serum, indicating a high sensitivity to the IgG/IgM/IgA ratio. Conclusion: All three binding assays allow monitoring of the antibody response in COVID-19-vaccinated individuals. However, the assay-specific differences hinder the definition of a common protective threshold in BAU/ml. Our results highlight the need for the thoughtful use of conversion factors and consideration of method-specific differences. To improve the management of future pandemics and harmonize total antibody assays, we should strive for reference material with a well-characterized Ig isotype composition. [ABSTRACT FROM AUTHOR]

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More than 3 years have passed since the emergence of COVID-19. On 8 May 2023, COVID-19 in Japan was downgraded to Category 5 by the Infectious Disease Control Law. In Japan, at the beginning of the COVID-19 pandemic in 2020, cases of infection and deaths from severe disease were few compared with those in Western countries. However, in the medical field, screening for COVID-19 was given top priority, resulting in confusion and proving disadvantageous for many patients. The overreaction to COVID-19 as the most important issue in society can be attributed largely to statements by infectious disease experts. In addition, the mRNA vaccine emerged in 2021, and most of the population was vaccinated up to two times within a short period of less than 1 year because infectious disease experts strongly promoted vaccination. After 2022, when vaccination progressed and the Omicron strain, which is an attenuated strain, became the mainstay of SARS-CoV-2, the number of severe cases of COVID-19 decreased significantly; however, the number of infected people increased dramatically instead. A significant portion of the population is thought to have hybrid immunity due to vaccination plus natural infection and maintains high antibody titer levels. Henceforth, additional vaccination should be given preferentially to those who will benefit most from it. Conversely, measures against COVID-19 caused serious damage to the economy and society. Policies that not only address countermeasures against infection, but also those that encompass the economy and society as a whole, are necessary.

Children infected with SARS-CoV-2 are often asymptomatic or have mild symptoms. The studies on the seroprevalence kinetics of SARS-CoV-2 antibodies in children are limited. We conducted a cross-sectional survey of the positive rate of the SARS-CoV-2 IgG in pediatric patients without suspected COVID-19 infection between January 2007 and March 2022. We defined the serum samples from the pre-pandemic and pandemic groups (1st–6th waves). Totally, 2557 samples were collected and no samples from the pre-pandemic group or the 1st–4th waves were positive for IgG. There were 4/661 and 16/373 positives at the 5th and 6th waves, respectively. At the 5th wave, the prevalence of IgG was 1.3% in children aged 1–4 years. At the 6th wave, in children <1 year of age, the prevalence was 4.0%, and 2.4%, 5.3%, 5.2% and 10% in age groups 1–4, 5–9, 10–14 and 15–18 years, respectively. In conclusions, the pre-pandemic samples were negative, and the IgG positivity increased during the later period of the pandemic. [ABSTRACT FROM AUTHOR]

Background: In sub-Saharan Africa many people who inject drugs (PWID) are living with undiagnosed or untreated HIV and experience high levels of poverty and conditions that can contribute to worse outcomes from SARS-CoV-2 infection. Identifying the burden of SARS-CoV-2 infection in marginalized populations like PWID may contribute to controlling the pandemic. Methods: This is a nested cross-sectional study within an ongoing cohort study that recruits PWID living with HIV and their injecting and/or sexual partners at needle and syringe program sites and methadone clinics in Kenya. Blood samples were collected from consenting participants at enrollment to determine SARS-CoV-2 antibodies using a Platellia BioRad SARS-CoV-2 total antibody enzyme-linked immunosorbent assay. Baseline data were collected on HIV status, antiretroviral therapy and methadone adherence. We used logistic regression to identify factors associated with antibody positivity and descriptive statistics to report SARS-CoV-2 antibody prevalence. Results: One thousand participants were enrolled between April and July 2021, of whom 323 (32.3%) were women and 677 (67.7%) were men. Median age of participants was 36 years (interquartile range: 30, 42). SARS-CoV-2 antibody positivity was found in 309 (30.9%) participants. Disruption in obtaining methadone service was reported by 106 (24.3%) of the participants. Men were significantly less likely than women to have SARS-CoV-2 antibodies (adjusted odds ratio [aOR] = 0.68, 95% confidence interval [CI] 0.51, 0.95; p < 0.01) Participants who reported a sexual or injecting partner diagnosed with SARS-CoV-2 were twofold more likely to have SARS-CoV-2 antibodies detected (aOR = 2.21, 95% CI 1.06, 4.58; p < 0.032). Living with HIV was not associated with presence of SARS-CoV-2 antibodies. Conclusion: The seroprevalence of SARS-CoV-2 of 30.9% in this cohort suggests high transmission rates within this population. SARS-CoV-2 seroprevalence was similar for people living with and without HIV. A large portion of this population was noted to have had disruption in access to harm reduction services. Key findings: We found a high seroprevalence of SARS-CoV-2 antibodies in people who inject drugs and their sexual and injecting partners. We also found that participants who reported a sexual or injecting partner diagnosed with SARS-CoV-2 were more likely to have SARS-C0V-2 antibody positivity. Living with HIV was not associated with presence of SARS-CoV-2 antibodies. A large proportion of people who inject drugs was noted to have had disruptions in access to harm reduction services during the study period. Key implications Kenya's national healthcare policymakers should implement special interventions like increased access to 'take-home doses' of methadone and waivers for daily in-person check--ns for this population during current and future crises to maintain continuity of treatment and access to harm reduction services. [ABSTRACT FROM AUTHOR]

The emergence of the SARS-CoV-2 Omicron variant has raised concerns due to its increased transmissibility and potential implications on clinical characteristics and outcomes in infected individuals. The aims of this report were to study the profile of SARS-CoV-2 infection with omicron variant, investigate the infection outcome, reinfection rates with associated factors, antibody levels, and explore the associations between biochemical markers and disease severity. This prospective cohort study was conducted in Duhok city in the Northern of Iraq. All volunteers with confirmed SARS-CoV-2 RT–PCR and confirmed Omicron infection who were older than 18 years old and agreed to participate were recruited for this study. The study was carried out from January to April 2022. There were 234 cases of confirmed SARS-CoV-2 RT–PCR Omicron infection. The mean age was 48.12±17.3 years, 43.2% were vaccinated, and 40.2% were male. Among the recruited patients, 99.1% recovered and did not need hospitalization. In this study, (38.9%) had a history of previously confirmed COVID-19 infection. Reinfection was significantly higher in females than males (p=0.04; OR= 0.56). It was found that the IgG antibody levels were higher in patients who received Pfizer-BioNTech than in those who received other vaccines (p=0.001). The levels of IgG were also significantly higher in patients with mild infection (p=0.046), whereas the levels of D-dimer were significantly higher in patients with severe cases of the infection compared to those with mild or moderate cases (p=0.001). Additionally, the levels of C-reactive protein (CRP) were observed to be higher in individuals with moderate cases of infection than in mild and severe cases (0.001). Individuals who contracted the Omicron strain generally had positive outcomes. Reinfection with the Omicron variant was relatively high. IgG levels were higher in patients with mild disease, implying that they were associated with decreased disease severity. We found significant associations between D-dimer levels and the severity of the disease. Additional research is required to investigate the long-term effects of Omicron infection. [ABSTRACT FROM AUTHOR]

More than 3 years have passed since the emergence of COVID-19. On 8 May 2023, COVID-19 in Japan was downgraded to Category 5 by the Infectious Disease Control Law. In Japan, at the beginning of the COVID-19 pandemic in 2020, cases of infection and deaths from severe disease were few compared with those in Western countries. However, in the medical field, screening for COVID-19 was given top priority, resulting in confusion and proving disadvantageous for many patients. The overreaction to COVID-19 as the most important issue in society can be attributed largely to statements by infectious disease experts. In addition, the mRNA vaccine emerged in 2021, and most of the population was vaccinated up to two times within a short period of less than 1 year because infectious disease experts strongly promoted vaccination. After 2022, when vaccination progressed and the Omicron strain, which is an attenuated strain, became the mainstay of SARS-CoV-2, the number of severe cases of COVID-19 decreased significantly; however, the number of infected people increased dramatically instead. A significant portion of the population is thought to have hybrid immunity due to vaccination plus natural infection and maintains high antibody titer levels. Henceforth, additional vaccination should be given preferentially to those who will benefit most from it. Conversely, measures against COVID-19 caused serious damage to the economy and society. Policies that not only address countermeasures against infection, but also those that encompass the economy and society as a whole, are necessary. [ABSTRACT FROM AUTHOR]

The serology surveillance of SARS-CoV-2 antibodies represents a useful tool for monitoring protective immunity in the population. We compared the performance of three SARS-CoV-2 antibody serological immunoassays in 600 vaccinated subjects after the BNT162b2 mRNA COVID-19 vaccine. All serum samples were evaluated by three different immunoassays for detecting anti-SARS-COV-2 antibodies. All SARS-CoV-2 antibody serological immunoassays could detect, when present, a post-vaccine humoral immune response. Median (interquartile range, IQR) anti-S-RBD IgG, Access SARS-CoV-2 IgG (1st IS) and Access SARS-CoV-2 IgG II levels of the subjects investigated were, respectively, 687 BAU/mL (131–2325), 419 IU/mL (58–1091) and 104 AU/mL (14–274). By studying a cohort of unvaccinated subjects, without previous COVID-19 infection, we found a high specificity for all methods. A high correlation was found between IgG titres. Considering the kinetics of subjects with multiple doses, we observed that percentage decreasing gradients were comparable across methods. Our results suggest that all the SARS-CoV-2 antibody serological immunoassays evaluated in this study are suitable for monitoring IgG titers over time. This study contributes to a better understanding of antibody response in vaccinated subjects using some currently available assays. [ABSTRACT FROM AUTHOR]

Abstract Background In sub-Saharan Africa many people who inject drugs (PWID) are living with undiagnosed or untreated HIV and experience high levels of poverty and conditions that can contribute to worse outcomes from SARS-CoV-2 infection. Identifying the burden of SARS-CoV-2 infection in marginalized populations like PWID may contribute to controlling the pandemic. Methods This is a nested cross-sectional study within an ongoing cohort study that recruits PWID living with HIV and their injecting and/or sexual partners at needle and syringe program sites and methadone clinics in Kenya. Blood samples were collected from consenting participants at enrollment to determine SARS-CoV-2 antibodies using a Platellia BioRad SARS-CoV-2 total antibody enzyme-linked immunosorbent assay. Baseline data were collected on HIV status, antiretroviral therapy and methadone adherence. We used logistic regression to identify factors associated with antibody positivity and descriptive statistics to report SARS-CoV-2 antibody prevalence. Results One thousand participants were enrolled between April and July 2021, of whom 323 (32.3%) were women and 677 (67.7%) were men. Median age of participants was 36 years (interquartile range: 30, 42). SARS-CoV-2 antibody positivity was found in 309 (30.9%) participants. Disruption in obtaining methadone service was reported by 106 (24.3%) of the participants. Men were significantly less likely than women to have SARS-CoV-2 antibodies (adjusted odds ratio [aOR] = 0.68, 95% confidence interval [CI] 0.51, 0.95; p

Background: More eligibility criteria have been added for blood donors to warrant safety of blood donations during the COVID-19 pandemic. The aim of this study was to assess the seroprevalence of antibodies to SARS-CoV-2 among blood donors and to study the lifestyle of asymptomatic cases.Methods: One thousand, three hundred twelve voluntary blood donors were enlisted in this study in the University Hospital from September to December 2021. Samples were tested for SARS-CoV-2 antibody. Donor’s lifestyle was analyzed. Results: 95.4% of the studied group were males, the seroprevalence of SARS-CoV-2 antibody was 83.3% and related to gender, regular donation, type of donation, and more frequent when donors shared transport and accommodation. 9.5% were found to possess cough/fever or a history of contact with COVID-19 patients. Conclusion: Blood donors proved to give an idea about virus spreading among healthy population. Additional risk factors can be identified to ensure safety of transfusion.

BackgroundQuantification of the SARS-CoV-2-specific immune response by serological immunoassays is critical for the management of the COVID-19 pandemic. In particular, neutralizing antibody titers to the viral spike (S) protein have been proposed as a correlate of protection (CoP). The WHO established the First International Standard (WHO IS) for anti-SARS-CoV-2 immunoglobulin (Ig) (NIBSC 20/136) to harmonize binding assays with the same antigen specificity by assigning the same unitage in binding antibody units (BAU)/ml.MethodIn this study, we analyzed the S1-specific antibody response in a cohort of healthcare workers in Germany (n = 76) during a three-dose vaccination course over 8.5 months. Subjects received either heterologous or homologous prime-boost vaccination with ChAdOx1 nCoV-19 (AstraZeneca) and BNT162b2 (Pfizer-BioNTech) or three doses of BNT162b2. Antibodies were quantified using three anti-S1 binding assays (ELISA, ECLIA, and PETIA) harmonized to the WHO IS. Serum levels of neutralizing antibodies were determined using a surrogate virus neutralization test (sVNT). Binding assays were compared using Spearman’s rank correlation and Passing–Bablok regression.FindingsAll assays showed good correlation and similar antibody kinetics correlating with neutralizing potential. However, the assays show large proportional differences in BAU/ml. ECLIA and PETIA, which detect total antibodies against the receptor- binding domain (RBD) within the S1 subunit, interact similarly with the convalescent plasma-derived WHO IS but differently with vaccine serum, indicating a high sensitivity to the IgG/IgM/IgA ratio.ConclusionAll three binding assays allow monitoring of the antibody response in COVID-19-vaccinated individuals. However, the assay-specific differences hinder the definition of a common protective threshold in BAU/ml. Our results highlight the need for the thoughtful use of conversion factors and consideration of method-specific differences. To improve the management of future pandemics and harmonize total antibody assays, we should strive for reference material with a well-characterized Ig isotype composition.

ABSTRACT The 50% plaque reduction neutralization assay (PRNT50) has been previously used to assess the neutralization capacity of donor plasma against wild-type and variant of concern (VOC) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging data suggest that plasma with an anti-SARS-CoV-2 level of ≥2 × 104 binding antibody units/mL (BAU/mL) protects against SARS-CoV-2 Omicron BA.1 infection. Specimens were collected using a cross-sectional random sampling approach. For PRNT50 studies, 63 previously analyzed specimens by PRNT50 versus SARS-CoV-2 wild-type, Alpha, Beta, Gamma, and Delta were analyzed by PRNT50 versus Omicron BA.1. The 63 specimens plus 4,390 specimens (randomly sampled regardless of serological evidence of infection) were also tested using the Abbott SARS-CoV-2 IgG II Quant assay (anti-spike [S]; Abbott, Chicago, IL, USA; Abbott Quant assay). In the vaccinated group, the percentages of specimens with any measurable PRNT50 versus wild-type or VOC were wild type (21/25 [84%]), Alpha (19/25 [76%]), Beta (18/25 [72%]), Gamma (13/25 [52%]), Delta (19/25 [76%]), and Omicron BA.1 (9/25 [36%]). In the unvaccinated group, the percentages of specimens with any measurable PRNT50 versus wild type or VOC were wild-type SARS-CoV-2 (16/39 [41%]), Alpha (16/39 [41%]), Beta (10/39 [26%]), Gamma (9/39 [23%]), Delta (16/39 [41%]), and Omicron BA.1 (0/39) (Fisher's exact tests, vaccinated versus unvaccinated for each variant, P

Yan-Fen Tang,1,2,&ast; Jun-Yan Han,2– 4,&ast; Ai-Min Ren,1,2 Li Chen,1,2 Tian-Jiao Xue,1,2 Yong-Hong Yan,2– 4 Xi Wang,2– 4 Yu Wang,1,2 Rong-Hua Jin2,3,5 1Department of Respiratory, Beijing Ditan Hospital Capital Medical University, Beijing, 100015, People’s Republic of China; 2National Center for Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, People’s Republic of China; 3Institute of Infectious Diseases, Beijing Key Laboratory of Emerging Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, People’s Republic of China; 4Beijing Institute of Infectious Diseases, Beijing, 100015, People’s Republic of China; 5Changping Laboratory, Beijing, 102299, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Rong-Hua Jin, National Center for Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun Dongjie, Chaoyang District, Beijing, 100015, People’s Republic of China, Tel +86 10 84322009, Fax +86 10 84322146, Email ronghuajin@ccmu.edu.cn Yu Wang, Department of Respiratory, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun Dongjie, Chaoyang District, Beijing, 100015, People’s Republic of China, Tel +86 10 84322963, Fax +86 10 84322146, Email wangyu20171021@163.comObjective: To explore the long-term effects of SARS-Cov-2 infection on the pulmonary function in the severe convalescent COVID-19 patients for 6 to 9 months follow-up in Beijing, China.Methods: A total of 64 cases of COVID-19 patients were recruited for the study and discharged from the Beijing Ditan Hospital, Capital Medical University, for 6 to 9 months. COVID-19 patients were divided into non-severe (mild and moderate) and severe groups. The follow-up investigated the lung function tests, the novel coronavirus antibody (IgM and IgG), chest CT and blood tests.Results: About 25.00% (16/64) patients had pulmonary ventilation dysfunction and 35.9% (23/64) had diffusion dysfunction. In the severe group, 56.50% (13/23) individuals showed decreased diffusion function. The diffusion dysfunction of the severe group was significantly decreased than the non-severe group (P = 0.01). Among 56 cases, the positive rate of IgG titers was 73.2% (41/56). The result of chest CT showed 55.36% (31/56) cases in nodules, 44.64% (25/56) in strip-like changes, 37.5% (21/56) in-ground glass shadow, and 5.36% (3/56) in grid shadow, which was significantly different between the severe group and the non-severe group. Patients tended to have ground glass changes in the severe group while nodules in the non-severe group.Conclusion: For the 6 to 9 months in convalescent COVID-19 patients, 56.50% (13/23) of severe patients had pulmonary diffusion dysfunction. Convalescent COVID-19 patients should have their pulmonary function regularly tested, especially those with severe illness.Keywords: COVID-19, pulmonary function, SARS-CoV-2 antibody, severe patients, chest CT, follow-up

Objective: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody titers level and duration of elevated levels are considered important indicators for confirming the efficacy of coronavirus disease 2019 (COVID-19) vaccines. The objective of this study was to demonstrate the changes in antibody titers after the second and third doses of the COVID-19 vaccine, and to determine the antibody titers in cases of spontaneous infection with SARS-CoV-2 after vaccination. Materials and Methods: From June 2021 to February 2023, IgG-type SARS-CoV-2 antibody titers were measured in 127 participants, including 74 outpatients and 53 members of staff, at the Osaka Dental University Hospital (64 males and 63 females, mean age 52.3 ± 19.0 years). Results: Consistent with previous reports, the SARS-CoV-2 antibody titer decreased with time, not only after the second dose but also after the third dose of the vaccine if there was no spontaneous COVID-19 infection. We also confirmed that the third booster vaccination was effective in increasing the antibody titer. A total of 21 cases of natural infections were observed after administering two or more doses of the vaccine. Thirteen of these patients had post-infection antibody titers exceeding 40,000 AU/mL, and some cases continued to maintain antibody titers in the tens of thousands of AU/mL even after more than 6 months had passed since infection. Conclusions: The rise in and duration of antibody titers against SARS-CoV-2 are considered important indicators for confirming the efficacy of novel COVID-19 vaccines. A longitudinal follow-up of antibody titers after vaccination in larger studies is warranted. [ABSTRACT FROM AUTHOR]

Cancer is an important public health problem. Prostate cancer is one of the most common cancers among men. In Poland, the incidence of this type of cancer is constantly growing. Considering the appearance of a new coronavirus in December 2019 (SARS-CoV-2) and the fact that oncology patients, including those with prostate cancer, are particularly vulnerable to infection, it is recommended to get vaccinated against COVID-19. In our study, we determined the level and prevalence of antibodies against SARS-CoV-2 IgG in patients with prostate cancer compared to the control group and whether the patients' ages affected the level of antibodies. PCa patients and controls were divided into two age groups: 50–59 years and 60–70 years. We also analyzed the level of antibodies in patients belonging to the relevant risk groups for prostate cancer (the European Society of Urology risk group classification of prostate cancer). For the study, we used the Microblot-Array COVID-19 IgG test to detect antibodies against the three main SARS-CoV-2 antigens: NCP, RBD, and S2. Our results showed that prostate cancer patients had significantly lower levels of anti-SARS-CoV-2 IgG antibodies compared to controls. In addition, age also affected the decrease in the number of IgG antibodies. The level of antibodies in the intermediate/high-risk group was lower compared to the low-risk group. [ABSTRACT FROM AUTHOR]

Background: The rise in antibody titers against the novel coronavirus (SARS-CoV-2) and its duration are considered an important indicator for confirming the effect of a COVID-19 vaccine, and self-paid tests of antibody titer are conducted in many facilities nationwide. Methods: The relationship between the number of days after the second and third dose of vaccines, age, and antibody titer was determined from the medical records of general internal medicine clinics that conducted self-paid testing of the SARS-CoV-2 antibody titer using Elecsys Anti-SARS-CoV-2 S (Roche Diagnostics); the relationship between the number of days after two or more doses of vaccines and antibody titer was also determined. We also examined the antibody titers in cases of spontaneous infection with SARS-CoV-2 after two or more doses of the vaccine. Results: Log-transformed SARS-CoV-2 antibody titers measured within 1 month from the second or third dose of vaccine showed a negative correlation with age (p < 0.05). In addition, the log-transformed antibody titers also showed a negative correlation trend with the number of days after the second dose of vaccine (p = 0.055); however, there were no significant correlations between the log-transformed antibody titers and the number of days after the third dose of vaccine. The median antibody titer after the third vaccination was 18,300 U/mL, more than 10 times the median antibody titer after the second dose of vaccine, of 1185 U/mL. There were also some cases of infection after the third or fourth dose of vaccine, with antibody titers in the tens of thousands of U/ml after infection, but the patients still received further booster vaccinations after the infection. Conclusions: The antibody titers after the third vaccination did not attenuate after a short follow-up period of one month, while they tended to attenuate after the second vaccination. It is considered that many people in Japan received further booster vaccinations after spontaneous infection, even though they already had antibody titers in the tens of thousands of U/mL due to "hybrid immunity" after spontaneous infection following two or more doses of vaccine. The clinical significance of the booster vaccination in this population still needs to be thoroughly investigated and should be prioritized for those with low SARS-CoV-2 antibody titers. [ABSTRACT FROM AUTHOR]

Individuals at increased risk for severe coronavirus disease-2019 (COVID-19) outcomes, due to compromised immunity or other risk factors, would benefit from objective measures of vulnerability to infection based on vaccination or prior infection. The authors reviewed published data to identify a specific role and interpretation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike-targeted serology testing. Specific recommendations are provided for an evidence-based and clinically-useful interpretation of SARS-CoV-2 spike-targeted serology to identify vulnerability to infection and potential subsequent adverse outcomes. Decreased vaccine effectiveness among immunocompromised individuals is linked to correspondingly high rates of breakthrough infections. Negative results on SARS-CoV-2 antibody tests are associated with increased risk for subsequent infection. "Low-positive" results on semiquantitative SARS-CoV-2 spike-targeted antibody tests may help identify persons at increased risk as well. Standardized SARS-CoV-2 spike-targeted antibody tests may provide objective information on the risk of SARS-CoV-2 infection and associated adverse outcomes. This holds especially for high-risk populations that demonstrate a relatively high rate of seronegativity. The widespread availability of such tests presents an opportunity to refine risk assessment for individuals with suboptimal SARS-CoV-2 antibody levels and to promote effective interventions. Interim federal guidance would support physicians and patients while additional investigations are pursued. [ABSTRACT FROM AUTHOR]

Background: Due to elderly residents, nursing homes/assisted living facilities were the most affected places in COVID-19 pandemic. Besides symptomatic patients, asymptomatic patients were detected during routine screening. Aim: This study aims to determine the factors that affect antibody response and viral shedding in stool samples after natural exposure to the virus in residents and staff who recovered from COVID-19 before the vaccine was available. Methods: This prospective cross-sectional study was conducted at the nation's highest-capacity Residential and Nursing Home. Blood samples were collected between December 15, 2020 and January 15, 2021 from participating residents and staff for anti-SARS-CoV-2 antibody testing. Stool samples were obtained for SARS-CoV-2 PCR testing 2 months after COVID-19. The Social Sciences (SPSS) program version 15.0 was used for statistical analysis. The Mann–Whitney U test compared SARS‐CoV‐2 antibody concentration between two groups. Results: Four hundred sixty-four (52.3%) residents and 424 (47.7%) staff participated. Entirely 259 (29.2%) participants were anti-SARS-CoV-2 IgG (+) and 255 (28.7%) were SARS-CoV-2 PCR (+). Both antibody and PCR positivity was detected in 196 (76.9%). In PCR (−) group, 63 (10.0%) participants were SARS-CoV‐2 IgG (+). Antibody titers were found highest in SARS-CoV-2 PCR (+) male residents. SARS-CoV-2 IgG titers were significantly high in SARS-CoV-2 PCR (+) and hospitalized participants regardless of age. Stool samples were obtained from 61(23.9%) participants and were found negative. Conclusion: A durable SARS-CoV‐2 IgG antibody response was monitored at least 9 months after the participants were diagnosed with COVID-19. SARS-CoV-2 antibody positivity was detected 76.9% in PCR (+) and 10.0% in PCR (−) participants. Knowing the duration of detectable antibodies is an important finding for developing disease prevention and public health strategies. [ABSTRACT FROM AUTHOR]

Objective: We aimed to assess the seroprevalence of SARS-CoV-2 infection and associated factors among Turkish HCWs, before the Covid-19 vaccination program in January 2021. Material and methods: We performed antibody assessment against SARS-CoV-2 in blood samples from participants using the Elecsys® Anti-SARS-CoV-2 electrochemiluminescence immunoassay. Samples with a cut-off index (COI; signal sample/cut-off) Results: 714 HCWs, 487 women (68.2%), were included in our study. The mean age of the participants was 35.9 ± 8.4 (min:18, max: 62). 370 (51.8%) HCWs's the antibody level was negative, and 344 (48.2%) was positive. While 47.1% (n=122) of the HCWs with positive RT-PCR were antibody positive, 48.8% (n=222) were negative. There was no statistically significant difference in mean age and age groups (p values ​​0.338 and 0.414, respectively). Also, there was no statistically significant difference in antibody levels by gender (p=0.236). There was no significant difference between antibody positivity according to the presence of comorbidity, and the risk area studied (p=0.556, p=0.335, respectively). There was a statistically significant difference between lung involvement and antibody positivity during Covid-19 infection (p= Conclusion: In our study, the seroprevalence of SARS-CoV-2 antibodies in HCWs was higher than the average population and approximately fifty percent. Multicenter studies with more HCWs would be helpful to determine overall seroprevalence rates.

Serological severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies determination in healthcare personnels with a increased risk of infection is important for detecting asymptomatic coronavirus disease 2019 (COVID-19) and post-disease immunity. Purpose of study were to determine the seroprevelance of healthcare personnels with COVID-19 in university hospital. 439 healthcare personnels working at Biruni University Medical Faculty Hospital between March 2020 to January 2021 were included to the study. All participants were divided into groups based on the results of their immunoglobulin G (IgG) antibodies against novel coronavirus in blood test, collecting nasopharyngeal and oropharyngeal swabs reverse transcriptasepolymerase chain reaction (RT-PCR), and thorax computed tomography (CT). Group 1: Antibody positivity and RT- PCR negativity, Group 2: RT-PCR positivity without lung involvement, Group 3: RT-PCR positivity with lung involvement. The RT-PCR positivity was detected as 32.8 % (n=144) in all healthcare personnels, 68.8 % of RT-PCR positive healthcare personnels were symptomatic and 15.3 % of them had lung involvement. The IgG antibody positivity was detected as 41 % (n=180) in all healthcare personnels. The antibody positivity (p=0.353) and titers were similar in the healthcare personnels (p=0.361). Risk of COVID-19 and contagiousness is high in healthcare personnels under pandemic conditions. Additionally the antibody positivity and antibody titer are higher in those who have symptomatic disease compared to those who have asymptomatic. [Med-Science 2022; 11(1.000): 154-8]

The accelerated development of the first generation COVID-19 vaccines has saved millions of lives, and potentially more from the long-term sequelae of SARS-CoV-2 infection. The most successful vaccine candidates have used the full-length SARS-CoV-2 spike protein as an immunogen. As expected of RNA viruses, new variants have evolved and quickly replaced the original wild-type SARS-CoV-2, leading to escape from natural infection or vaccine induced immunity provided by the original SARS-CoV-2 spike sequence. Next generation vaccines that confer specific and targeted immunity to broadly neutralising epitopes on the SARS-CoV-2 spike protein against different variants of concern (VOC) offer an advance on current booster shots of previously used vaccines. Here, we present a targeted approach to elicit antibodies that neutralise both the ancestral SARS-CoV-2, and the VOCs, by introducing a specific glycosylation site on a non-neutralising epitope of the RBD. The addition of a specific glycosylation site in the RBD based vaccine candidate focused the immune response towards other broadly neutralising epitopes on the RBD. We further observed enhanced cross-neutralisation and cross-binding using a DNA-MVA CR19 prime-boost regime, thus demonstrating the superiority of the glycan engineered RBD vaccine candidate across two platforms and a promising candidate as a broad variant booster vaccine.

Background: More eligibility criteria have been added for blood donors to warrant safety of blood donations during the COVID-19 pandemic. The aim of this study was to assess the seroprevalence of antibodies to SARS-CoV-2 among blood donors and to study the lifestyle of asymptomatic cases. Methods: One thousand, three hundred twelve voluntary blood donors were enlisted in this study in the University Hospital from September to December 2021. Samples were tested for SARS-CoV-2 antibody. Donor's lifestyle was analyzed. Results: 95.4% of the studied group were males, the seroprevalence of SARS-CoV-2 antibody was 83.3% and related to gender, regular donation, type of donation, and more frequent when donors shared transport and accommodation. 9.5% were found to possess cough/fever or a history of contact with COVID-19 patients. Conclusion: Blood donors proved to give an idea about virus spreading among healthy population. Additional risk factors can be identified to ensure safety of transfusion. [ABSTRACT FROM AUTHOR]

A homogeneous PCR-based assay for sensitive and specific detection of antibodies in serum or dried blood spots (DBS) is presented and the method is used to monitor individuals infected with or vaccinated against SARS-CoV-2. Detection probes were prepared by conjugating the recombinant spike protein subunit 1 (S1), containing the receptor binding domain (RBD) of SARS-CoV-2, to each of a pair of specific oligonucleotides. The same was done for the nucleocapsid protein (NP). Upon incubation with serum or DBS samples, the bi- or multivalency of the antibodies (IgG, IgA or IgM) brings pairs of viral proteins with their conjugated oligonucleotides in proximity, allowing the antibodies to be detected by a modified proximity extension assay (PEA). Anti-S1 and anti-NP antibodies could be detected simultaneously from one incubation reaction. This Antibody PEA (AbPEA) test uses only 1 µl of neat or up to 100,000-fold diluted serum or one ø1.2 mm disc cut from a DBS. All 100 investigated sera and 21 DBS collected prior to the COVID-19 outbreak were negative, demonstrating a 100% specificity. The area under the curve, as evaluated by Receiver Operating Characteristic (ROC) analysis reached 0.998 (95%CI: 0.993–1) for samples taken from 11 days after symptoms onset. The kinetics of antibody responses were monitored after a first and second vaccination using serially collected DBS from 14 individuals. AbPEA offers highly specific and sensitive solution-phase antibody detection without requirement for secondary antibodies, no elution step when using DBS sample in a simple procedure that lends itself to multiplex survey of antibody responses. • Highly sensitive PCR-based antibody detection. • Antibody Proximity Extension Assay (AbPEA). • Detection of SARS-CoV-2 antibodies from finger-prick dried blood spots (DBS). • Homogeneous serological assay suitable for multiplexing. [ABSTRACT FROM AUTHOR]

HIV infection is a significant independent risk factor for severe coronavirus disease 2019 (COVID-19) disease and death. We summarize COVID-19 vaccine responses in people with HIV (PWH). A systematic literature review of studies from January 1, 2020, to March 31, 2022, of COVID-19 vaccine immunogenicity in PWH from multiple databases was performed. Twenty-eight studies from 12 countries were reviewed. While 22 (73%) studies reported high COVID-19 vaccine seroconversion rates in PWH, PWH with lower baseline CD4 counts, CD4/CD8 ratios, or higher baseline viral loads had lower seroconversion rates and immunologic titers. Data on vaccine-induced seroconversion in PWH are reassuring, but more research is needed to evaluate the durability of COVID-19 vaccine responses in PWH. [ABSTRACT FROM AUTHOR]

The advancement in biosensors can overcome the challenges faced by conventional diagnostic techniques for the detection of the highly infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hence, the development of an accurate, rapid, sensitive, and selective diagnostic technique can mitigate adverse health conditions caused by SARS-CoV-2. This work proposes the development of an electrochemical immunosensor based on bio-nanocomposites for the sensitive detection of SARS-CoV-2 antibodies through the differential pulse voltammetry (DPV) electroanalytical method. The facile synthesis of chitosan-functionalized titanium dioxide nanoparticles (TiO2-CS bio-nanocomposites) is performed using the sol-gel method. Characterization of the TiO2-CS bio-nanocomposite is accomplished using UV-vis spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The electrochemical performance is studied using cyclic voltammetry (CV), DPV, and electrochemical impedance spectroscopy (EIS) for its electroanalytical and biosensing capabilities. The developed immunosensing platform has a high sensitivity with a wide range of detection from 50 ag mL−1 to 1 ng mL−1. The detection limit of the SARS-CoV-2 antibody in buffer media is obtained to be 3.42 ag mL−1 and the limit of quantitation (LOQ) to be 10.38 ag mL−1. The electrochemical immunosensor has high selectivity in different interfering analytes and is stable for 10 days. The results suggest that the developed electrochemical immunosensor can be applicable for real sample analysis and further high-throughput testing. [ABSTRACT FROM AUTHOR]

Monitoring antibody prevalence is a valuable tool to evaluate the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a community, identify risk factors, and assess the impact of clinical and public health intervention strategies. The antibody prevalence of SARS-CoV-2 in children in the United States in early 2022 was estimated by the Centers for Disease Control and Prevention to be 74.2%, using seroprevalence from a variety of sources. A study by the New Jersey Department of Health in late 2022/early 2023 in unvaccinated children found a lower prevalence, 68% when using a gum swab method to detect antibodies. This study compared the accuracy of the gum swab method to detect antibodies with simultaneously obtained serological samples in additional children. This cross-sectional study recruited well children, not vaccinated for SARS-CoV-2, aged 18 months to 11 years, who were scheduled for routine bloodwork at an inner-city university-based pediatric clinic. With parental consent, an extra 5 cc of blood and a gum swab sample were collected. Results from Diabetomics CovAb SARS-CoV-2 gum swab antibody test and Rutgers New Jersey Medical School enzyme-linked immunosorbent assay serology test for spike protein antibody were compared. The seropositivity of these paired samples was compared using McNemar's test, Cohen's kappa statistic, and other diagnostic accuracy statistics. From June through August 2023, 86 children were recruited. Antibody positivity by gum swab was 70.9% and by serology was 87.2%. The Cohen's kappa statistic was 0.39 indicating minimal agreement and McNemar's test was significant ( P -value of 0.0010). Compared with serology, gum swab was 78.7% sensitive (95% CI 68.7% to 87.3%) and 81.8% specific (95% CI 48.2% to 97.7%). Positive and negative predictive values were 97.5% and 29.9%, respectively, and accuracy was 79.0%. Sensitivity in non-Hispanic versus Hispanic children was 74.2% versus 82.5%, and in children 6-11 years versus 18 months to 5 years, it was 74.2% versus 81.8%. While the gum swab method of antibody detection is not as sensitive or specific as serology, sample collection can be done in settings where phlebotomy is not feasible. This method could be useful in non-clinical settings such as surveillance, for assessing epidemiological trends and associations., Importance: Recently a study determining the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in unvaccinated children in NJ (Katic et al. 2023. Pediatric Academic Societies Meeting; Washington, D.C. https://2023.pas-meeting.org/searchbyposterbucket.asp?bm=Public+Health+%26+Prevention&t=Public+Health+%26+Prevention&pfp=Track) was conducted using a gum swab method for antibody detection. The Diabetomics CovAB test, which qualitatively identifies antibodies to SARS-CoV-2 spike protein, is a point-of-care, low-cost test, that is easy to administer in children. While this test provides sensitive and specific results in adults [US Food and Drug Administration (FDA). 2022. Center for devices and radiological health. EUA authorized serology test performance. Available from: https://www.fda.gov/medical-devices/covid-19-emergency-use-authorizations-medical-devices/eua-authorized-serology-test-performance], data on its accuracy in children is lacking. As a follow-up to the above-mentioned study, we compared the results of the gum swab test to a serologic antibody test. We found that the gum swab test was inferior to serology but was fairly sensitive and specific with a high positive predictive value. While the test is not ideal for diagnostic purposes in children it can be a valuable tool for public health officials and pediatricians to understand the extent of past health interventions., Competing Interests: The authors declare no conflict of interest.

Objective To assess three severe acute respiratorysyndrome coronavirus 2 (SARS-CoV-2) enzyme linked immunosorbent assays (ELISA) and one pseudotype lentivirus-based neutralization test (ppNAT) in detecting the convalescent plasma antibody levles from COVID-19. Methods 30 COVID-19 convalescent plasma samples were screened for antibodies against SARS-CoV-2 using three kinds of SARS-CoV-2 ELISA reagents and one ppNAT test in Shenzhen. The controls consisted of plasma samples from 32 healthy blood donors in February 2019. The diagnostic efficacy analysis of various SARS-CoV-2 ELISA reagents was performed using real-time fluorescent Polymerase Chain Reaction (RT-PCR). We also analyzed correlation between different immunological reagents and the age, gender, hospitalization, and severity of illness. Results The positive yielding rate of ppNAT and three kinds of IgG ELISA was higher than that of IgM ELISA. The positive yielding rates of three kinds of IgG ELISA were 100%(30/30), 93.33%(28/30), and 96.67%(29/30) respectively, while the yielding rates in control group were all 0. The positive yielding rate of three IgM ELISAs were 93.33%(28/30), 70%(21/30)and 46.67% (14/30). All the cases from negative control group were negative for IgG and IgM. Pearson correlation coefficient was calculated; there was a strong correlation between ELISA reagent 2 IgG and ELISA reagent 3 IgG (r=0.765, P0.05). Conclusion In the convalescent plasma with nucleic acid confirmed covid-19, the yielding rates of different IgM antibodies varied greatly. Antibody levels were influenced by age to some extent.

Abstract Background Lebanon, a small country in the Middle East, remains severely affected by the COVID-19 pandemic. Seroprevalence surveys of anti-SARS-CoV-2 antibodies provide accurate estimates of SARS-CoV-2 infection and hence evaluate the extent of the pandemic. The present study aimed to evaluate the prevalence of SARS-CoV-2 antibodies in Lebanon and to compare the estimated cumulative number of COVID-19 cases with the officially registered number of laboratory-confirmed cases up to January 15, 2021. Methods A nationwide population-based serosurvey study was conducted in Lebanon between December 7, 2020, and January 15, 2021, before the initiation of the national vaccination program. The nCOVID-19 IgG & IgM point-of-care (POCT) rapid test was used to detect the presence of anti-SARS-COV-2 immunoglobulin G (IgG) in the blood. Seroprevalence was estimated after weighting for sex, age, and area of residence and adjusting for the test performance. Results Of the 2058 participants, 329 were positive for IgG SARS-COV-2, resulting in a crude seroprevalence of 16.0% (95% CI 14.4–17.6). The weighed seroprevalence was 15.9% (95% CI of 14.4 and 17.4). After adjusting for test performance, the population weight-adjusted seroprevalence was 18.5% (95% CI 16.8–20.2). This estimate implies that 895,770 individuals of the general population were previously infected by COVID-19 up to January 15, 2021 in Lebanon. The overall estimated number of subjects with previous SARS-CoV-2 infection was three times higher than the officially reported cumulative number of confirmed cases. Seroprevalence was similar across age groups and sexes (p-value > 0.05). However, significant differences were revealed across governorates. Conclusions Our results suggest that the Lebanese population is still susceptible to SARS-CoV-2 infection and far from achieving herd immunity. These findings represent an important contribution to the surveillance of the COVID-19 pandemic in Lebanon and to the understanding of how this virus spreads. Continued surveillance for COVID-19 cases and maintaining effective preventive measures are recommended to control the epidemic spread in conjunction with a national vaccination campaign to achieve the desired level of herd immunity against COVID-19.

BackgroundUnderstanding the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination will enable accurate counseling and inform evolving vaccination strategies. Little is known about antibody response following booster vaccination in people living with HIV (PLWH).MethodsWe enrolled SARS-CoV-2 vaccinated PLWH and controls without HIV in similar proportions based on age and comorbidities. Participants completed surveys on prior SARS-CoV-2 infection, vaccination, and comorbidities, and provided self-collected dried blood spots (DBS). Quantitative anti-spike IgG and surrogate viral neutralization assays targeted wild-type (WT), Delta, and Omicron variants. We also measured quantitative anti-nucleocapsid IgG. The analysis population had received full SARS-CoV-2 vaccination plus one booster dose. Bivariate analyses for continuous outcomes utilized Wilcoxon tests and multivariate analysis used linear models.ResultsThe analysis population comprised 140 PLWH and 75 controls with median age 58 and 55 years, males 95% and 43%, and DBS collection on 112 and 109 days after the last booster dose, respectively. Median CD4 count among PLWH was 760 cells/mm3 and 91% had an undetectable HIV-1 viral load. Considering WT, Delta, and Omicron variants, there was no significant difference in mean quantitative anti-spike IgG between PLWH (3.3, 2.9, 1.8) and controls (3.3, 2.9, 1.8), respectively (p-values=0. 771, 0.920, 0.708). Surrogate viral neutralization responses were similar in PLWH (1.0, 0.9, and 0.4) and controls (1.0, 0.9, 0.5), respectively (p-values=0.594, 0.436, 0.706).ConclusionsPLWH whose CD4 counts are well preserved and persons without HIV have similar anti-spike IgG antibody levels and viral neutralization responses after a single SARS-CoV-2 booster vaccination.

Background: A primary series of 2-dose SARS-CoV-2 vaccines based on an ancestral strain generate inadequate neutralizing antibodies against the SARS-CoV-2 Omicron variant. This study aimed to describe the immune response from giving healthy school-aged children who previously received 2 inactivated vaccines an mRNA BNT162b2 booster. Methods: Healthy children aged 5–11 years who received 2 doses of CoronaVac or Covilo were enrolled and received 10 µg BNT162b2 intramuscularly. Neutralizing antibody against Omicron variant was measured at pre-booster and 14–21 days post-booster by surrogate virus neutralization test (sVNT, %inhibition) and pseudovirus neutralization test (pVNT, ID50). Antibody responses were compared with a parallel cohort of children who received 2 doses of BNT162b2 3 weeks apart. Results: From April to May 2022, 59 children with a mean age (SD) of 8.5 years (1.7) were enrolled: 20 CoronaVac and 39 Covilo recipients. The median interval from the primary series was 49 days (IQR 33–51). After booster, the geometric means (GMs) of sVNT and pVNT were 72.2 %inhibition (95 %CI 67.2–77.6) and 499 (95 %CI 399–624), respectively. The proportion of children with sVNT against Omicron strain ≥68 %inhibition increased from none to 70.2 %. The geometric mean ratio (GMR) of sVNT and pVNT compared with a parallel cohort were 4.3 and 12.2, respectively. The GMR of sVNT and pVNT between children who received booster dose at >6-week interval were 1.2 (95 %CI 1.1–1.3). and 1.8 (95 %CI 1.2–2.7) compared with 4–6 weeks interval. Conclusion: A regimen of 2-dose of inactivated vaccine followed by BNT162b2 booster dose elicited high neutralizing antibody against the Omicron variants in healthy school-aged children.

Background Immunization of vulnerable populations with distinct immunity often results in suboptimal immunogenicity, durability, and efficacy. Methods Safety and immunogenicity profiles of BNT162b2 messenger RNA coronavirus disease 2019 (COVID-19) vaccine, among people living with human immunodeficiency virus (HIV), were evaluated in 28 perinatally HIV-infected patients under antiretroviral therapy (ART) and 65 healthy controls (HCs) with no previous history of COVID-19. Thus, we measured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific humoral and CD4+ T cell responses. Samples were collected before vaccination (baseline, day [D] 0), at the second dose (D21), and at 4 weeks (D28) and 6 months (D180) after D0. Proteomic profiles at D0 and D28 were assessed with a multiplexed proximity extension assay (Olink) on plasma samples. Results All HIV-infected patients mounted similar anti–SARS-CoV-2 humoral responses to those of HCs, albeit with lower titers of anti-trimeric S at D28 (P = .01). Only peripheral blood mononuclear cells of HIV-infected patients demonstrated at D28 an impaired ability to expand their specific (CD40L+) CD4+ T-cell populations. Similar humoral titers were maintained between the 2 groups at 6-months follow-up. We additionally correlated baseline protein levels to either humoral or cellular responses, identifying clusters of molecules involved in immune response regulation with inverse profiles between the 2 study groups. Conclusions Responses of ART-treated HIV-infected patients, compared to those of HCs, were characterized by distinct features especially within the proteomic compartment, supporting their eligibility to an additional dose, similarly to the HC schedule. [ABSTRACT FROM AUTHOR]

Here, we developed a liquid crystal (LC)-based immunosensor for the sensitive and selective detection of anti-severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) nucleocapsid (N) protein antibodies. LC molecules were aligned parallel to the anisotropic gold nanostructure to induce uniform alignment, and a uniform texture was observed under a polarised optical microscope (POM). After the antigen was immobilised on the nanostructure, the surface was incubated with the antibodies to form antigen-antibody complexes. This led to interference in the uniform alignment of the LC molecules, and a random texture was observed under POM. However, when the surface was incubated with control proteins, the alignment of the LC molecules did not change and a uniform texture was observed under POM. This texture change of the LC optical images was evaluated as quantified values using grey-scale intensity measurements. The lower detection limit was determined to be 100 ng/mL in phosphate-buffered saline (PBS) solution, which is lower than the clinically relevant concentration in the µg/mL range. The developed LC-based immunosensor has high sensitivity and selectivity for the detection of the anti-SARS-CoV-2N protein antibody, which can be easily detected with a small sample volume of 2 µL. [ABSTRACT FROM AUTHOR]

Background: The impact of chronic health conditions (CHCs) on serostatus post-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is unknown. Methods: We assessed serostatus post-SARS-CoV-2 vaccination among fully vaccinated adult residents of Jefferson County, Kentucky, USA, from April 2021 to August 2021. Serostatus was determined by qualitative analysis of SARS-CoV-2-specific Spike IgG antibodies via enzyme-linked immunoassay (ELISA) in peripheral blood samples. Results: Of the 5178 fully vaccinated participants, 51 were seronegative and 5127 were seropositive. Chronic kidney disease (CKD) and autoimmune disease showed the highest association with negative serostatus in fully vaccinated individuals. The absence of any CHC was strongly associated with positive serostatus. The risk of negative serostatus increased as the total number of pre-existing CHCs increased. Similarly, the use of two or more CHC-related medications was associated with seronegative status. Conclusions: The presence of any CHC, especially CKD or autoimmune disease, increased the likelihood of seronegative status among individuals who were fully vaccinated to SAR-CoV-2. This risk increased with a concurrent increase in number of comorbidities, especially with multiple medications. The absence of any CHC was protective and increased the likelihood of a positive serological response. These results will help develop appropriate guidelines for booster doses and targeted vaccination programs. [ABSTRACT FROM AUTHOR]

In a few months, the SARS-CoV-2 virus caused a worldwide COVID-19 pandemic. In Poland, 6 million cases of the disease and 113,000 deaths from COVID-19 have been reported. Healthcare workers (HCWs) constitute one of the main COVID-19 risk groups. The Microblot-Array COVID-19 IgG assay was used to detect antibodies against three major SARS-CoV-2 antigens: nucleocapsid (NCP), RBD, and Spike 2 (S2). The aim of our study was to determine the seroprevalence and titer of anti-SARS-CoV-2 IgG antibodies—NCP, RBD, and S2—as markers of the humoral response in vaccinated and unvaccinated HCWs. The study included 203 persons who were divided into four groups: "COVID-19 Vaccinated", "COVID-19 Unvaccinated", "Non-COVID-19 Vaccinated", and "Non-COVID-19 Unvaccinated". The obtained results indicate that both seroprevalence and the antibody titer are the highest in the "COVID-19 Vaccinated" group. There is no so-called sterile vaccination, and after 6 months from the second dose of vaccine, most vaccinated people have a fairly high level of antibodies. We suggest that multiple vaccination and continuous testing are necessary. The Microblot-Array assay can distinguish between antibodies acquired after infection and/or vaccination. [ABSTRACT FROM AUTHOR]

Yusuke Hanioka,1 Ryo Morita,2 Keiko Yamagami,1 Shuhei Yao,1 Ryota Nakamura,1 Tomoyuki Nakamura,1 Katsushu Shimizu,3 Toshimasa Yamaguchi,3 Hitoshi Goto1 1Department of Internal Medicine, Osaka City General Hospital, Osaka, Japan; 2Department of Infectious Diseases, Osaka City General Hospital, Osaka, Japan; 3Department of Primary Care and Advanced Triage Section, Osaka City General Hospital, Osaka, JapanCorrespondence: Yusuke HaniokaDepartment of Internal Medicine, Osaka City General Hospital, 2-13-22 Miyakojima-Hondori, Miyakojima-ku, Osaka, 534-0021, JapanTel +81-6-6929-1221Fax +81-6-6929-2041Email y-hanioka@med.osakacity-hp.or.jpPurpose: It is important to understand how COVID-19 is affecting general outpatient services, since hospitals see a wide variety of patients. This study aimed to evaluate the incidence and clinical picture of COVID-19 in general outpatient services. Currently, the diagnosis of COVID-19 depends strongly on the results of polymerase chain reaction (PCR) assays. However, since the sensitivity of PCR tests for SARS-CoV-2 is not high enough to assure confidence. On the other hand, the SARS-CoV-2 antibody (Ab) test is highly sensitive after 2 weeks of symptom onset, and might complement the PCR test. Therefore, we measured Ab in addition to PCR to obtain a more accurate clinical profile of COVID-19, which might be helpful in building future practice strategies.Patients: The study patients were those who visited our department for the first time between November 2020 and March 2021 and fulfilled the enrolment criteria.Methods: All patients underwent total SARS-CoV-2 Ab testing, and PCR tests were performed in only some of them; patients were classified according to the performance of PCR tests for comparisons.Results: Ninety-four patients who underwent Ab testing during the study period were eligible for study enrolment, and the PCR test was performed in 40 of them. Only one patient was diagnosed with acute stage COVID-19 based on a positive PCR test. Antibodies were positive in six (6.4%) of the 94 patients. Five of the six Ab-positive patients were negative for PCR, and the test was not performed in the sixth patient. All the six patients had prior symptoms suggestive of infection, and respiratory symptoms were more noticeable than fever. The Ab positivity rate was significantly higher than published data.Conclusion: COVID-19 is not rare in general outpatient services and can be missed based on PCR tests alone. The diagnosis should be made from a comprehensive perspective.Keywords: COVID-19, SARS-CoV-2 antibody, outpatient service, fever

ABSTRACT There is evidence that COVID-19 convalescent plasma may improve outcomes of patients with impaired immune systems; however, more clinical trials are required. Although we have previously used a 50% plaque reduction/neutralization titer (PRNT50) assay to qualify convalescent plasma for clinical trials and virus-like particle (VLP) assays to validate PRNT50 methodologies, these approaches are time-consuming and expensive. Here, we characterized the ability of the Abbott severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2 characterized by both VLP assays and PRNT50. Plasma specimens previously tested in wild-type, Alpha, Beta, Gamma, and Delta VLP neutralization assays were selected based on availability. Selected specimens were evaluated by the Abbott SARS-CoV-2 IgG II Quant assay [Abbott anti-Spike (S); Abbott, Chicago, IL], and values in units per milliliter were converted to binding antibody units (BAU) per milliliter. Sixty-three specimens were available for analysis. Abbott SARS-CoV-2 IgG II Quant assay values in BAU per milliliter were significantly different between high- and low-titer specimens for wild-type (Mann-Whitney U = 42, P < 0.0001), Alpha (Mann-Whitney U = 38, P < 0.0001), Beta (Mann-Whitney U = 29, P < 0.0001), Gamma (Mann-Whitney U = 0, P < 0.0001), and Delta (Mann-Whitney U = 42, P < 0.0001). A conservative approach using the highest 95% confidence interval (CI) values from wild-type and variant of concern (VOC) SARS-CoV-2 experiments would identify a potential Abbott SARS-CoV-2 IgG II Quant assay cutoff of ≥7.1 × 103 BAU/mL. IMPORTANCE The United States Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for the use of COVID-19 convalescent plasma (CCP) to treat hospitalized patients with COVID-19 in August 2020. However, by 4 February 2021, the FDA had revised the convalescent plasma EUA. This revision limited the authorization for high-titer COVID-19 convalescent plasma and restricted patient groups to hospitalized patients with COVID-19 early in their disease course or hospitalized patients with impaired humoral immunity. Traditionally our group utilized 50% plaque reduction/neutralization titer (PRNT50) assays to qualify CCP in Canada. Since that time, the Abbott SARS-CoV-2 IgG II Quant assay (Abbott, Chicago IL) was developed for the qualitative and quantitative determination of IgG against the SARS-CoV-2. Here, we characterized the ability of the Abbott SARS-CoV-2 IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2.

Background and Objectives: During the pandemic of CO­VID-19, additional blood donor eligibility criteria have been added to ensure safety of donors and donations. The aim of this study is to estimate the seroprevalence of SARS-CoV-2 antibody in eligible donors and to study the demography and lifestyle of asymptomatic cases. Materials and Methods: One thousand four hundred eighteen eligible donors were enrolled in this study in the Dubai Blood Donation Center from August to December 2020. Blood samples were tested for SARS-CoV-2 antibody. Donors’ demographic characteristics and lifestyle were studied further. The χ2 test was used to analyze the data association. Results: 88.4% of the studied group were males, 85% were from age 17 to 45 years, and 53% were regular donors. The seroprevalence of SARS-CoV-2 antibody was 13.5% and significantly related to gender, frequency of donation, collection site, type of donation, and more frequent when donors shared transport and accommodation. Blood group and age had no significant association. 5.5% were found to have cough/fever or a history of contact with positive COVID-19 patients. Conclusions: The seroprevalence of SARS-CoV-2 antibody was 13.5% among eligible blood donors, and hence the current eligibility criteria allow asymptomatic COVID-19 patients to donate blood. The seroprevalence was seen more in first time donors, suggesting that regular blood donors are safer. Additional risk factors related to lifestyle can be identified to ensure safety of transfusion during COVID-19 pandemic.

Background We studied humoral responses after coronavirus disease 2019 (COVID-19) vaccination across varying causes of immunodeficiency. Methods Prospective study of fully vaccinated immunocompromised adults (solid organ transplant [SOT], hematologic malignancy, solid cancers, autoimmune conditions, human immunodeficiency virus [HIV]) versus nonimmunocompromised healthcare workers (HCWs). The primary outcome was the proportion with a reactive test (seropositive) for immunoglobulin G to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain. Secondary outcomes were comparisons of antibody levels and their correlation with pseudovirus neutralization titers. Stepwise logistic regression was used to identify factors associated with seropositivity. Results A total of 1271 participants enrolled: 1099 immunocompromised and 172 HCW. Compared with HCW (92.4% seropositive), seropositivity was lower among participants with SOT (30.7%), hematological malignancies (50.0%), autoimmune conditions (79.1%), solid tumors (78.7%), and HIV (79.8%) (P <.01). Factors associated with poor seropositivity included age, greater immunosuppression, time since vaccination, anti-CD20 monoclonal antibodies, and vaccination with BNT162b2 (Pfizer) or adenovirus vector vaccines versus messenger RNA (mRNA)-1273 (Moderna). mRNA-1273 was associated with higher antibody levels than BNT162b2 or adenovirus vector vaccines after adjusting for time since vaccination, age, and underlying condition. Antibody levels were strongly correlated with pseudovirus neutralization titers (Spearman r  = 0.89, P  < .0001), but in seropositive participants with intermediate antibody levels, neutralization titers were significantly lower in immunocompromised individuals versus HCW. Conclusions Antibody responses to COVID-19 vaccines were lowest among SOT and anti-CD20 monoclonal recipients, and recipients of vaccines other than mRNA-1273. Among those with intermediate antibody levels, pseudovirus neutralization titers were lower in immunocompromised patients than HCWs. Additional SARS-CoV-2 preventive approaches are needed for immunocompromised persons, which may need to be tailored to the cause of immunodeficiency. [ABSTRACT FROM AUTHOR]