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Objectives: Autoimmune activation by COVID-19 infection/vaccination has been postulated to be responsible for initiating or reactivating multiple types of oral mucosal immune disorders. These include: oral lichen planus; oral pemphigoid; either bullous pemphigoid or mucous membrane pemphigoid with oral involvement; pemphigus vulgaris with oral involvement; and Sjögren disease. In addition, chronic conditions such as oral burning, xerostomia, or changes in taste and/or smell have also been linked to COVID-19 infection/vaccination. Data sources: Part 1 (mucosal conditions): an English-language literature review of Pubmed, Web of Science, Scopus, and Embase was performed searching cases of oral lichen planus, oral bullous pemphigoid, mucous membrane pemphigoid, pemphigus vulgaris, and COVID-19 infection/vaccination, with additional cases from the authors’ clinical practice presented. Part 2 (nonmucosal conditions): Cases of initiated or flared Sjögren disease, chronic oral burning, or xerostomia after COVID-19 infection/vaccination from the authors’ clinical practice were aggregated. Results: The literature review discovered 29 cases of oral lichen planus following COVID-19 infection/vaccination. For bullous pemphigoid, 10 cases were identified after infection/vaccination. The number of pemphigus vulgaris cases following infection/vaccination was 28. The majority of mucosal cases were reported after vaccination. Most reported initial disease, but a substantial amount included recurrences of existing diseases. Nonmucosal disease: Sjögren disease, chronic oral burning, or xerostomia after COVID-19 infection/vaccination cases totaled 12 cases identified from the authors’ clinical practice, with the majority occurring after infection. Conclusions: Chronic conditions after infection with COVID-19 or vaccination remain relatively rare and self-limited, yet reinforce the importance of comprehensive history taking involving COVID-19 to differentiate potential etiologic factors for these conditions. [ABSTRACT FROM AUTHOR]

Nucleocapsid antibody assays can be used to estimate SARS-CoV-2 infection prevalence in regions implementing spike-based COVID-19 vaccines. However, poor sensitivity of nucleocapsid antibody assays in detecting infection after vaccination has been reported. We derived a lower cutoff for identifying previous infections in a large blood donor cohort (N = 142,599) by using the Ortho VITROS Anti-SARS-CoV-2 Total-N Antibody assay, improving sensitivity while maintaining specificity >98%. We validated sensitivity in samples donated after self-reported swab-confirmed infections diagnoses. Sensitivity for first infections in unvaccinated donors was 98.1% (95% CI 98.0-98.2) and for infection after vaccination was 95.6% (95% CI 95.6-95.7) based on the standard cutoff. Regression analysis showed sensitivity was reduced in the Delta compared with Omicron period, in older donors, in asymptomatic infections,

OBJECTIVE: Although vaccination confidence is declining globally, there is little detailed information from low- and middle-income countries about factors influencing routine vaccination behavior in these contexts. METHODS: In mid-2022, we surveyed people who gave birth in Kenya between 2017-2022, and asked them about their childrens vaccination history and about hypothesized correlates of vaccination per the Behavioural and Social Drivers of Vaccination model. RESULTS: Of 873 children in this sample, 117 (13%) were under-vaccinated (i.e., delayed or missing vaccine dose(s)) - and under-vaccination was more common among births during the COVID-19 pandemic (2020-2022) versus pre-pandemic (2017-2019). In multi-level multivariable models, children of respondents who expressed concerns about serious side effects from vaccines had significantly higher odds of missed vaccine dose(s) (aOR 2.06, 95 % CI 1.14-3.72), and there was a strong association between having more safety concerns now versus before the COVID-19 pandemic (aOR missed dose(s) 4.44, 95 % CI 1.71-11.51; aOR under-vaccination 3.03, 95 % CI 1.28-7.19). People with greater trust in health workers had lower odds of having a child with missed vaccine dose(s) (aOR 0.85, 95 % CI 0.75-0.97). People who reported higher patient-centered quality of vaccination care had much lower odds of having children with delayed or missed vaccine dose(s) (aOR missed dose(s) 0.14, 95 % CI 0.04-0.58; aOR under-vaccination 0.27, 95 % CI 0.10-0.79). CONCLUSIONS: These findings highlight potential strategies to improve vaccine coverage: greater focus on patient-centered quality of care, training healthcare workers on how to address safety concerns about vaccines, and building trust in the health care system and in health workers.

Despite efforts to increase childhood vaccination coverage in the Democratic Republic of the Congo (DRC), approximately 20% of infants have not started their routine immunization schedule (zero-dose). The present study aims to evaluate the relative influence of geospatial access to health facilities and caregiver perceptions of vaccines on the vaccination status of children in rural DRC. Pooled data from two consecutive nationwide immunization surveys conducted in 2022 and 2023 were used. Geographic accessibility was assessed based on travel time from households to their nearest health facility using the AccessMod 5 model. Caregiver attitudes to vaccination were assessed using the survey question How good do you think vaccines are for your child? We used logistic regression to assess the relationship between geographic accessibility, caregiver attitudes toward vaccination, and their childs vaccination status. Geographic accessibility to health facilities was high in rural DRC, with 88% of the population living within an hours walk to a health facility. Responding that vaccines are Bad, Very Bad, or Dont Know relative to Very Good for children was associated with a many-fold increased odds of a zero-dose status (ORs 69.3 [95%CI: 63.4-75.8]) compared to the odds for those living 60+ min from a health facility, relative to

A vaccine for coccidioidomycosis is likely to undergo trials in the near future. In this paper, we raise 4 questions that should be answered before its use and offer our solutions to these questions. These include defining the goals of vaccination, determining who should be vaccinated, how to measure vaccine immunity and protection, and how to address vaccine hesitancy and denial.

The aim of this project was to increase willingness to receive the influenza vaccine to the optimal rate of ≥ 70%. Low acuity adult patients who visited an Emergency Department (ED) were assessed regarding their willingness to receive the influenza vaccine before and after an educational intervention that included a provider recommendation and an educational handout. A total of seventy-six patients (n = 76) were assessed. Patients willingness to receive the influenza vaccine rose from 29% pre-intervention to 72% post-intervention without disrupting the clinical flow in a busy ED. Similar vaccine educational strategies can be applied to influenza and other vaccines in EDs  to increase vaccination willingness in patients, including those who use the ED as a primary point of contact for healthcare, decreasing the burden of influenza illness in the community.

OBJECTIVE: Vaccination has engendered a spectrum of public opinions, with social media acting as a crucial platform for health-related discussions. The emergence of artificial intelligence technologies, such as large language models (LLMs), offers a novel opportunity to efficiently investigate public discourses. This research assesses the accuracy of ChatGPT, a widely used and freely available service built upon an LLM, for sentiment analysis to discern different stances toward Human Papillomavirus (HPV) vaccination. METHODS: Messages related to HPV vaccination were collected from social media supporting different message formats: Facebook (long format) and Twitter (short format). A selection of 1,000 human-evaluated messages was input into the LLM, which generated multiple response instances containing its classification results. Accuracy was measured for each message as the level of concurrence between human and machine decisions, ranging between 0 and 1. RESULTS: Average accuracy was notably high when 20 response instances were used to determine the machine decision of each message: .882 (SE = .021) and .750 (SE = .029) for anti- and pro-vaccination long-form; .773 (SE = .027) and .723 (SE = .029) for anti- and pro-vaccination short-form, respectively. Using only three or even one instance did not lead to a severe decrease in accuracy. However, for long-form messages, the language model exhibited significantly lower accuracy in categorizing pro-vaccination messages than anti-vaccination ones. CONCLUSIONS: ChatGPT shows potential in analyzing public opinions on HPV vaccination using social media content. However, understanding the characteristics and limitations of a language model within specific public health contexts remains imperative.

How human genetic variation contributes to vaccine effectiveness in infants is unclear, and data are limited on these relationships in populations with African ancestries. We undertook genetic analyses of vaccine antibody responses in infants from Uganda (n = 1391), Burkina Faso (n = 353) and South Africa (n = 755), identifying associations between human leukocyte antigen (HLA) and antibody response for five of eight tested antigens spanning pertussis, diphtheria and hepatitis B vaccines. In addition, through HLA typing 1,702 individuals from 11 populations of African ancestry derived predominantly from the 1000 Genomes Project, we constructed an imputation resource, fine-mapping class II HLA-DR and DQ associations explaining up to 10% of antibody response variance in our infant cohorts. We observed differences in the genetic architecture of pertussis antibody response between the cohorts with African ancestries and an independent cohort with European ancestry, but found no in silico evidence of differences in HLA peptide binding affinity or breadth. Using immune cell expression quantitative trait loci datasets derived from African-ancestry samples from the 1000 Genomes Project, we found evidence of differential HLA-DRB1 expression correlating with inferred protection from pertussis following vaccination. This work suggests that HLA-DRB1 expression may play a role in vaccine response and should be considered alongside peptide selection to improve vaccine design.

As behavioural science is increasingly adopted by organizations, there is a growing need to assess the robustness and transferability of empirical findings. Here, we investigate the transferability of insights from various sources of behavioural science knowledge to field settings. Across three pre-registered randomized controlled trials (RCTs, N = 314,824) involving a critical policy domain-COVID-19 booster uptake-we field tested text-based interventions that either increased vaccinations in prior field work (RCT1, NCT05586204), elevated vaccination intentions in an online study (RCT2, NCT05586178) or were favoured by scientists and non-experts (RCT3, NCT05586165). Despite repeated exposure to COVID-19 vaccination messaging in our population, reminders and psychological ownership language increased booster uptake, replicating prior findings. However, strategies deemed effective by prediction or intention surveys, such as encouraging the bundling of COVID-19 boosters and flu shots or addressing misconceptions, yielded no detectable benefits over simple reminders. These findings underscore the importance of testing interventions transferability to real-world settings.

ImportanceIncreasing influenza vaccination rates is a public health priority. One method recommended by the US Centers for Disease Control and Prevention and others is for health systems to send reminders nudging patients to be vaccinated.ObjectiveTo evaluate and compare the effect of electronic health record (EHR)-based patient portal reminders vs text message reminders on influenza vaccination rates across a health system.Design, setting, and participantsThis 3-arm randomized clinical trial was conducted from September 7, 2022, to April 30, 2023, among primary care patients within the University of California, Los Angeles (UCLA) health system.InterventionsArm 1 received standard of care. The health system sent monthly reminder messages to patients due for an influenza vaccine by portal (arm 2) or text (arm 3). Arm 2 had a 2 × 2 nested design, with fixed vs responsive monthly reminders and preappointment vs no preappointment reminders. Arm 3 had 1 × 2 design, with preappointment vs no preappointment reminders. Preappointment reminders for eligible patients were sent 24 and 48 hours before scheduled primary care visits. Fixed reminders (in October, November, and December) involved identical messages via portal or text. Responsive portal reminders involved a September message asking patients about their plans for vaccination, with a follow-up reminder if the response was affirmative but the patient was not yet vaccinated.Main outcomes and measuresThe primary outcome was influenza vaccination by April 30, 2023, obtained from the UCLA EHR, including vaccination from pharmacies and other sources.ResultsA total of 262 085 patients (mean [SD] age, 45.1 [20.7] years; 237 404 [90.6%] adults; 24 681 [9.4%] children; 149 349 [57.0%] women) in 79 primary care practices were included (87 257 in arm 1, 87 478 in arm 2, and 87 350 in arm 3). At the entire primary care population level, none of the interventions improved influenza vaccination rates. All groups had rates of approximately 47%. There was no statistical or clinically significant improvement following portal vs text, preappointment reminders vs no preappointment reminders (portal and text reminders combined), or responsive vs fixed monthly portal reminders.Conclusions and relevanceAt the population level, neither portal nor text reminders for influenza vaccination were effective. Given that vaccine hesitancy may be a major reason for the lack of impact of portal or text reminders, more intensive interventions by health systems are needed to raise influenza vaccination coverage levels.Trial registrationClinicalTrials.gov Identifier: NCT05525494.

Introduction: Coronavirus 2019 (COVID-19) inequitably impacted minority populations and regions with limited access to healthcare resources. The Barnes-Jewish Emergency Department in St. Louis, MO, serves such a population. The COVID-19 vaccine is an available defense to help achieve community immunity. The emergency department (ED) is a potential societal resource to provide access to a vaccination intervention. Our objective in this study was to describe and evaluate a novel ED COVID-19 vaccine program, including its impact on the local surrounding underserved community.Methods: This was a retrospective, post-protocol implementation review of an ED COVID-19 vaccination program. Over the initial six-month period, we compiled data on all vaccinated patients out of the ED to evaluate demographic data and the impact on underserved regional areas.Results: We report a successful ED-based COVID-19 vaccine program (with over 1,000 vaccines administered). This program helped raise regional and state vaccination rates. Over 50% of the population that received the COVID-19 vaccine from the ED were from defined socially vulnerable patient populations. No adverse effects were documented.Conclusion: Operation CoVER (COVID-19 Vaccine in the Emergency Room) Saint Louis was able to successfully vaccinate a socially vulnerable patient population. This free, COVID-19 ED-based vaccine program with dedicated pharmacy support, was novel in emergency medicine practice. Similar ED-based vaccine programs could help with future vaccine distribution.

Three years after the start of the SARS-CoV-2 virus (COVID-19) pandemic, its effects continue to affect society and COVID-19 vaccination campaigns continue to be a topic of controversy and inconsistent practice. After experiencing spikes in COVID-19 cases, our University of California Davis Health Division of Hospital Medicine sought to understand the reasons underlying the low COVID-19 vaccination rates in our county and find approaches to improve the number of vaccinations among adults admitted to the inpatient setting. This quality improvement project aimed to increase COVID-19 primary and booster vaccine efforts through a multi-pronged approach of increased collaboration with specialised staff and optimisation of use of our electronic health record system.Our key interventions focused on developing a visual reminder of COVID-19 vaccine status using the functionality of our electronic medical record (EMR), standardising documentation of COVID-19 vaccine status and enhancing team-based vaccination discussions through team huddles and partnering with inpatient care coordinators. While our grassroots approach enhanced COVID-19 vaccination rates in the inpatient setting and had additional benefits such as increased collaboration among teams, system-level efforts often made a greater impact at our healthcare centre. For other institutions interested in increasing COVID-19 vaccination rates, our top three recommendations include integrating vaccination into pre-existing workflows, optimising EMR functionality and increasing vaccine accessibility in the inpatient setting.

BACKGROUND: The interpretation of relative vaccine effectiveness (rVE) of improved influenza vaccines is complex. Estimation of burden averted is useful to contextualise their potential impact across different seasons. For the population aged under 65 years in Australia, this study estimated the additional morbidity and mortality that could be averted using improved influenza vaccines. METHODS: We used observed, season-specific (2015-2019) influenza notification and influenza-coded hospitalisation frequencies and published modelled estimates of influenza-associated hospitalisations and deaths that occurred under the prevailing influenza vaccination coverage scenario. After back-calculating to the estimated burden in the population without vaccination, we applied published standard influenza vaccine effectiveness and coverage estimates to calculate the burden potentially averted by standard and improved influenza vaccines. A plausible range of rVE values were used, assuming 50% coverage. RESULTS: The percentage point difference in absolute vaccine effectiveness (VE) of an improved vaccine compared to a standard vaccine is directly proportional to its rVE and inversely proportional to the effectiveness of the standard vaccine. The incremental burden averted by an improved vaccine is a function of both its difference in absolute VE and the severity of the influenza season. Assuming an rVE of 15% with 50% coverage, the improved vaccine was estimated to additionally avert 1517 to 12,641 influenza notifications, 287 to 1311 influenza-coded hospitalisations and 9 to 33 modelled all-cause influenza deaths per year compared to the standard vaccine. CONCLUSIONS: Improved vaccines can have substantial clinical and population impact, particularly when the effectiveness of standard vaccines is low, and burden is high.

In 2022, an estimated 5 million persons in the WHO Region of the Americas (AMR) were living with chronic hepatitis B virus (HBV) infection, the leading cause of hepatocellular carcinoma and cirrhosis worldwide. Most chronic infections are acquired through mother-to-child transmission (MTCT) or horizontal transmission during childhood and are preventable with HBV vaccination, including a birth dose (HepB-BD), followed by 2-3 additional doses (HepB3) in infancy. The aim of the Pan American Health Organization (PAHO) Elimination of MTCT of HBV strategy (EMTCT Plus) is intented to reduce the prevalence of chronic HBV infection (measured as hepatitis B surface antigen [HBsAg]) among children to [less than or equal to]0.1% by achieving 1) [greater than or equal to]95% coverage with HepB-BD and HepB3 and 2) increasing HBsAg testing among pregnant women and provision of hepatitis B immunoglobulin to HBV-exposed neonates to [greater than or equal to]80%. By 2012, all 51 countries and territories (countries) in the AMR had provided HepB3 nationwide; and, by 2021, 34 (67%) had provided HepB-BD nationwide. Mathematical models were used to estimate that the HBsAg prevalence in children is [less than or equal to] 0.1% in 14 (28%) countries and at regional level. Three (6%) of 51 countries met the 95% coverage targets for both HepB3 and HepB-BD during both 2021 and 2022. Of these, 2 have probably met the criteria for EMTCT of HBV infection. In 2022, however, HepB3 coverage was [greater than or equal to] 10 percentage points lower in 15 (37%) of 41 countries with 2012 coverage data for comparison. These decreases in HepB3 coverage and the absence of HepB-BD from the routine immunization schedules in 17 countries threaten the Region's progress towards the EMTCT of HBV infection. Efforts to introduce HepB-BD and to maintain high HepB3 and HepB-BD coverage are necessary. En 2022, on estimait a 5 millions le nombre de personnes vivant avec une infection chronique par le virus de l'hepatite B (VHB) dans la Region OMS des Ameriques, principale cause de carcinome hepatocellulaire et de cirrhose dans le monde. La plupart des infections chroniques sont contractees par transmission mere-enfant (TME) ou par transmission horizontale pendant l'enfance et peuvent etre evitees grace a la vaccination contre le VHB, notamment par l'administration d'une dose a la naissance (DN-HepB), suivie de 2 a 3 doses supplementaires (HepB3) dans la petite enfance. La strategie d'elimination de la transmission mere-enfant du VHB (EMTCT Plus) de l'Organisation panamericaine de la Sante (OPS) vise a reduire la prevalence de l'infection chronique par le VHB (mesuree par une prevalence de l'antigene de surface du virus de l'hepatite B [AgHBs]) [less than or equal to]0,1% chez les enfants) en parvenant a: 1) une couverture [greater than or equal to]95% par la DN-HepB et la HepB3 et 2) une couverture [greater than or equal to]80% du depistage a la recherche de l'AgHBs chez les femmes enceintes et de l'administration d'immunoglobulines antihepatite B aux nouveau-nes exposes au VHB. En 2012, les 51 pays et territoires (ci-apres <>) de la Region des Ameriques administraient la HepB3 a l'echelle nationale; en 2021, 34 pays (67%) administraient la DN-HepB a l'echelle nationale. Des modeles mathematiques ont permis d'estimer que la prevalence de l'AgHBs chez les enfants etait [less than or equal to] 0,1% dans 14 pays (28%) et au niveau regional. Trois des 51 pays (6%) avaient atteint la cible d'une couverture de 95% par la HepB3 et la DN-HepB en 2021 et en 2022, dont 2 remplissaient probablement les criteres de l'elimination de la TME de l'infection par le VHB. En 2022, cependant, la couverture par la HepB3 etait inferieure de [greater than or equal to] 10 points de pourcentage dans 15 des 41 pays (37%) pour lesquels les donnees de couverture de 2012 etaient disponibles a des fins de comparaison. Cette diminution de la couverture par la HepB3 et l'absence de la DN-HepB dans les calendriers de vaccination systematique dans 17 pays menacent les progres de la Region vers l'elimination de la TME de l'infection par le VHB. Il est necessaire de deployer des efforts pour introduire la DN-HepB et maintenir une couverture elevee par la HepB3 et la DN-HepB., Introduction Globally, chronic HBV infection is the leading cause of hepatocellular carcinoma and cirrhosis. (1) In 2022, an estimated 5 million people in the AMR (2) had chronic HBV infection, [...]

The recommendations of the Immunization and Vaccines-related Implementation Research Advisory Committee (IVIR-AC) are based on discussions during a virtual meeting of IVIR-AC on 26 February-1 March 2024. (1) Four sessions [...]

BACKGROUND AND OBJECTIVES: In June 2022, the mRNA COVID-19 vaccination was recommended for young children. We examined clinical characteristics and factors associated with vaccination status among vaccine-eligible young children hospitalized for acute COVID-19. METHODS: We enrolled inpatients 8 months to

Vaccinating patients receiving dialysis may prevent morbidity and mortality in this vulnerable population. The National Forum of End-Stage Renal Disease Networks (the Forum) published a revised vaccination toolkit in 2021 to update evidence and recommendations on vaccination for patients receiving dialysis. Significant changes in the last 10 years include more data supporting the use of a high-dose influenza vaccine, the introduction of the Heplisav-B vaccine for hepatitis B, and changes in pneumococcal vaccines, including the approval of the PCV15 and PCV20 to replace the PCV13 and PPSV23 vaccines. Additional key items include the introduction of vaccines against severe acute respiratory syndrome coronavirus 2, the virus that causes coronavirus disease 2019 (COVID-19), and a new vaccine to prevent respiratory syncytial virus disease. Historically, influenza and pneumococcal vaccinations were routinely administered by dialysis facilities, and because of possible risks of hematogenous spread of hepatitis B, dialysis providers often have detailed hepatitis B vaccine protocols. In March 2021, COVID-19 vaccines were made available for dialysis facilities to administer, although with the end of the public health emergency, vaccine policies by dialysis facilities against COVID-19 remains uncertain. The respiratory syncytial virus vaccine was authorized in 2023, and how dialysis facilities will approach this vaccine also remains uncertain. This review summarizes the Forums vaccination toolkit and discusses the role of the dialysis facility in vaccinating patients to reduce the risk of severe infections.

We explore one systematic review and meta-analysis of both observational and randomized studies examining COVID-19 vaccines in 5- to 11-year-olds, which reported substantial benefits associated with vaccinating this age group. We discuss the limitations of the individual studies that were used to estimate vaccination benefits. The review included five observational studies that evaluated vaccine effectiveness (VE) against COVID-19 severe disease or hospitalization. All five studies failed to adequately assess differences in underlying health between vaccination groups. In terms of vaccination harms, looking only at the randomized studies, a significantly higher odds of adverse events was identified among the vaccinated compared with the unvaccinated. Observational studies are at risk of overestimating the effectiveness of vaccines against severe disease if healthy vaccinee bias is present. Falsification endpoints can provide valuable information about underlying healthy vaccinee bias. Studies that have not adequately ruled out bias due to better health among the vaccinated or more vaccinated should be viewed as unreliable for estimating the VE of COVID-19 vaccination against severe disease and mortality. Existing systematic reviews that include observational studies of the COVID-19 vaccine in children may have overstated or falsely inferred vaccine benefits due to unidentified or undisclosed healthy vaccinee bias.

We studied T-cell responses to SARS-CoV-2 in 19 pregnant subjects at different gestational weeks who received three doses of mRNA-based vaccination to prevent COVID-19. SARS-CoV-2 peptide pools were used for T-cell recognition studies: peptides were 15 amino acids long and had previously been defined in COVID-19-convalescent subjects. T-cell activation was evaluated with the AIM assay. Most subjects showed coordinated, spike-specific CD4+ and CD8+ T-cell responses and the development of T cell memory. Non-spike-specific T cells in subjects who were not aware of previous COVID-19 infection suggested a prior undetected, asymptomatic infection. CD4- CD8- double negative (DN) T cells were numerous, of which a percentage was specific for SARS-CoV-2 spike peptides. Regulatory T cells (Treg), both spike- and non-spike-specific, were also greatly expanded. Two Treg populations were defined: a population differentiated from naïve T cells, and pTreg, reverting from pro-inflammatory T cells. The Treg cells expressed CCR6, suggesting homing to the endometrium and vaginal epithelial cells. The pregnant women responded to SARS-CoV-2 vaccination. Asymptomatic COVID-19 was revealed by the T cell response to the non-spike peptides. The numerous DN T cells and Treg pointed our attention to new aspects of the adaptive immune response in vaccine recipients.

BackgroundHybrid immunity, from COVID-19 vaccination followed by SARS-CoV-2 infection acquired after its Omicron variant began predominating, has provided greater protection than vaccination alone against subsequent infection over 1-3 months of observation. Its longer-term protection is unknown.MethodsWe conducted a retrospective cohort study of COVID-19 case incidence among healthcare personnel (HCP) mandated to be vaccinated and report on COVID-19-associated symptoms, high-risk exposures, or known-positive test results to an employee health hotline. We compared cases with hybrid immunity, defined as incident COVID-19 during the first 6 weeks of Omicron-variant predominance (run-in period), to those with immunity from vaccination alone during the run-in period. Time until COVID-19 infection over 13 subsequent months (observation period) was analyzed by standard survival analysis.ResultsOf 5867 employees, 641 (10.9%, 95% confidence interval [CI]: 10.1%-11.8%) acquired hybrid immunity during the run-in period. Of these, 104 (16.2%, 95% CI: 13.5%-19.3%) experienced new SARS-CoV-2 infection during the 13-month observation period, compared to 2177 (41.7%, 95% CI: 40.3%-43.0%) of the 5226 HCP without hybrid immunity. Time until incident infection was shorter among the latter (hazard ratio: 3.09, 95% CI: 2.54-3.78).ConclusionsIn a cohort of vaccinated employees, Omicron-era acquired SARS-CoV-2 hybrid immunity was associated with significantly lower risk of subsequent infection over more than a year of observation-a time period far longer than previously reported and during which three, progressively more resistant, Omicron subvariants became predominant. These findings can inform institutional policy and planning for future COVID-19 additional vaccine dosing requirements for employees, for surveillance programs, and for risk modification efforts.

Malaria sterile immunity has been reproducibly induced by immunization with Plasmodium radiation-attenuated sporozoites (RAS). Analyses of sera from RAS-immunized individuals allowed the identification of P. falciparum antigens, such as the circumsporozoite protein (CSP), the basis for the RTS, S and R21Matrix-M vaccines. Similar advances in P. vivax (Pv) vaccination have been elusive. We previously reported 42% (5/12) of sterile protection in malaria-unexposed, Duffy-positive (Fy +) volunteers immunized with PvRAS followed by a controlled human malaria infection (CHMI). Using a custom protein microarray displaying 515 Pv antigens, we found a significantly higher reactivity to PvCSP and one hypothetical protein (PVX_089630) in volunteers protected against P. vivax infection. In mock-vaccinated Fy + volunteers, a strong antibody response to CHMI was also observed. Although the Fy- volunteers immunized with non-irradiated Pv-infected mosquitoes (live sporozoites) did not develop malaria after CHMI, they recognized a high number of antigens, indicating the temporary presence of asexual parasites in peripheral blood. Together, our findings contribute to the understanding of the antibody response to P. vivax infection and allow the identification of novel parasite antigens as vaccine candidates.Trial registration: ClinicalTrials.gov number: NCT01082341.

PURPOSE: Herpes zoster ophthalmicus (HZO) after COVID-19 vaccination has been reported in numerous case studies. However, no large-scale epidemiologic studies have been conducted to date. The purpose of this study was to determine whether COVID-19 vaccination is associated with an increased risk of HZO. DESIGN: Retrospective before-and-after risk interval analysis. METHODS: RESULTS: In total, 1,959,157 patients received a dose of a COVID-19 vaccine during the study period and met eligibility criteria. A total of 80 individuals without a prior history of HZO were included in the analysis because they developed HZO in the risk or control period. Patients had a mean age of 54.0 years (SD = 12.3 years). There were 45 cases of HZO in the risk interval after COVID-19 vaccination. There was not an increased risk of HZO after vaccination with BNT162b2 (IRR = 0.90, 95% CI: 0.49-1.69, P = .74), mRNA-1273 (IRR = 0.74, 95% CI: 0.36-1.54, P = .42), or Ad26.COV2.S (IRR = 0.50, 95% CI: 0.07-2.56, P = .42). CONCLUSIONS: This study found no evidence of increased risk of HZO after COVID-19 vaccination, providing reassurance for patients and providers who may be concerned about the safety profile of the COVID-19 vaccines.

BackgroundElicitation of broad immune responses is understood to be required for an efficacious preventative HIV vaccine. This Phase 1 randomized controlled trial evaluated whether administration of vaccine antigens separated at multiple injection sites vs combined, fractional delivery at multiple sites affected T-cell breadth compared to standard, single site vaccination.MethodsWe randomized 90 participants to receive recombinant adenovirus 5 (rAd5) vector with HIV inserts gag, pol and env via three different strategies. The Standard group received vaccine at a single anatomic site (n = 30) compared to two polytopic (multisite) vaccination groups: Separated (n = 30), where antigens were separately administered to four anatomical sites, and Fractioned (n = 30), where fractions of each vaccine component were combined and administered at four sites. All groups received the same total dose of vaccine.FindingsCD8 T-cell response rates and magnitudes were significantly higher in the Fractioned group than Standard for several antigen pools tested. CD4 T-cell response magnitudes to Pol were higher in the Separated than Standard group. T-cell epitope mapping demonstrated greatest breadth in the Fractioned group (median 8.0 vs 2.5 for Standard, Wilcoxon p = 0.03; not significant after multiplicity adjustment for co-primary endpoints). IgG binding antibody response rates to Env were higher in the Standard and Fractioned groups vs Separated group.InterpretationThis study shows that the number of anatomic sites for which a vaccine is delivered and distribution of its antigenic components influences immune responses in humans.FundingNational Institute of Allergy and Infectious Diseases, NIH.

BACKGROUND: Our previous study established a 2-dose regimen of high-dose trivalent influenza vaccine (HD-TIV) to be immunogenically superior compared to a 2-dose regimen of standard-dose quadrivalent influenza vaccine (SD-QIV) in pediatric allogeneic hematopoietic cell transplant (HCT) recipients. However, the durability of immunogenicity and the role of time post-HCT at immunization as an effect modifier are unknown. METHODS: This phase II, multi-center, double-blinded, randomized controlled trial compared HD-TIV to SD-QIV in children 3-17 years old who were 3-35 months post-allogeneic HCT, with each formulation administered twice, 28-42 days apart. Hemagglutination inhibition (HAI) titers were measured at baseline, 28-42 days following each dose, and 138-222 days after the second dose. Using linear mixed effects models, we estimated adjusted geometric mean HAI titer ratios (aGMR: HD-TIV/SD-QIV) to influenza antigens. Early and late periods were defined as 3-5 and 6-35 months post-HCT, respectively. RESULTS: During 3 influenza seasons (2016-2019), 170 participants were randomized to receive HD-TIV (n = 85) or SD-QIV (n = 85). HAI titers maintained significant elevations above baseline for both vaccine formulations, although the relative immunogenic benefit of HD-TIV to SD-QIV waned during the study. A 2-dose series of HD-TIV administered late post-HCT was associated with higher GMTs compared to the early post-HCT period (late group: A/H1N1 aGMR = 2.16, 95% confidence interval [CI] = [1.14-4.08]; A/H3N2 aGMR = 3.20, 95% CI = [1.60-6.39]; B/Victoria aGMR = 1.91, 95% CI = [1.01-3.60]; early group: A/H1N1 aGMR = 1.03, 95% CI = [0.59-1.80]; A/H3N2 aGMR = 1.23, 95% CI = [0.68-2.25]; B/Victoria aGMR = 1.06, 95% CI = [0.56-2.03]). CONCLUSIONS: Two doses of HD-TIV were more immunogenic than SD-QIV, especially when administered ≥6 months post-HCT. Both groups maintained higher titers compared to baseline throughout the season. CLINICAL TRIALS REGISTRATION: NCT02860039.

Influenza virus infection alters the promoter DNA methylation of key immune response-related genes, including type-1 interferons and proinflammatory cytokines. However, less is known about the effect of the influenza vaccine on the epigenome. We utilized a targeted DNA methylation approach to study the longitudinal effects (day 0 pre-vaccination and day 28 post-vaccination) on influenza vaccination responses in peripheral blood mononuclear cells. We found that baseline, pre-vaccination methylation profiles are associated with pre-existing, protective serological immunity. Additionally, we identified 481 sites that were differentially methylated between baseline and day 28 post-vaccination. These were enriched for genes involved in the regulation of the RIG-I signaling pathway, an important regulator of viral responses. Our results suggest that DNA methylation changes to components of the RIG-I pathway are associated with vaccine effectiveness. Therefore, immunization strategies that target this pathway may improve serological responses to influenza vaccination.

Human humoral immune responses to SARS-CoV-2 vaccines exhibit substantial inter-individual variability and have been linked to vaccine efficacy. To elucidate the underlying mechanism behind this variability, we conducted a genome-wide association study (GWAS) on the anti-spike IgG serostatus of UK Biobank participants who were previously uninfected by SARS-CoV-2 and had received either the first dose (n = 54,066) or the second dose (n = 46,232) of COVID-19 vaccines. Our analysis revealed significant genome-wide associations between the IgG antibody serostatus following the initial vaccine and human leukocyte antigen (HLA) class II alleles. Specifically, the HLA-DRB1∗13:02 allele (MAF = 4.0%, OR = 0.75, p = 2.34e-16) demonstrated the most statistically significant protective effect against IgG seronegativity. This protective effect was driven by an alteration from arginine (Arg) to glutamic acid (Glu) at position 71 on HLA-DRβ1 (p = 1.88e-25), leading to a change in the electrostatic potential of pocket 4 of the peptide binding groove. Notably, the impact of HLA alleles on IgG responses was cell type specific, and we observed a shared genetic predisposition between IgG status and susceptibility/severity of COVID-19. These results were replicated within independent cohorts where IgG serostatus was assayed by two different antibody serology tests. Our findings provide insights into the biological mechanism underlying individual variation in responses to COVID-19 vaccines and highlight the need to consider the influence of constitutive genetics when designing vaccination strategies for optimizing protection and control of infectious disease across diverse populations.

There is limited information on the antibody responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in subjects from developing countries with populations having a high incidence of co-morbidities. Here, we analysed the immunogenicity of homologous schemes using the ChAdOx1-S, Sputnik V, or BNT162b2 vaccines and the effect of a booster dose with ChAdOx1-S in middle-aged adults who were seropositive or seronegative to the SARS-CoV-2 spike protein before vaccination. The study was conducted post-vaccination with a follow-up of 4 months for antibody titre using enzyme-linked immunosorbent assay (ELISA) and pseudovirus (PV) neutralization assays (PNAs). All three vaccines elicited a superior IgG anti-receptor-binding domain (RBD) and neutralization response against the Alpha and Delta variants when administered to individuals with a previous infection by SARS-CoV-2. The booster dose spiked the neutralization activity among individuals with and without a prior SARS-CoV-2 infection. The ChAdOx1-S vaccine induced weaker antibody responses in infection-naive subjects. A follow-up of 4 months post-vaccination showed a drop in antibody titre, with about 20% of the infection-naive and 100% of SARS-CoV-2 pre-exposed participants with detectable neutralization capacity against Alpha pseudovirus (Alpha-PV) and Delta PV (Delta-PV). Our observations support the use of different vaccines in a country with high seroprevalence at the vaccination time.

BACKGROUND: Institutional mistrust has weakened COVID-19 mitigation efforts. Assessing to what extent institutional mistrust impacts parental decision making is important in formulating structural efforts for improving future pandemic response. We hypothesized that institutional mistrust is associated with lower parental endorsement for COVID-19 vaccination. METHODS: We distributed an online survey among parents from schools in areas with high levels of social vulnerability relative to the rest of San Diego County. We defined vaccination endorsement as having a child aged 5 years or older who received at least one COVID-19 vaccine dose or being very likely to vaccinate their child aged 6 months-4 years when eligible. Institutional mistrust reflected the level of confidence in institutions using an aggregate score from 11 to 44. We built a multivariable logistic regression model with potential confounding variables. FINDINGS: Out of 290 parents in our sample, most were female (87.6%), reported their child as Hispanic/Latino (73.4%), and expressed vaccination endorsement (52.1%). For every one-point increase in mistrust score, there was an 8% reduction in the likelihood of participants endorsing vaccination for their child. Other statistically significant correlates that were positively associated with vaccination endorsement included parent vaccination status, child age, parent age, and Hispanic/Latino ethnicity. CONCLUSION: Our study further demonstrates how institutional mistrust hinders public response during health emergencies. Our findings also highlight the importance of building confidence in institutions and its downstream effects on pandemic preparedness and public health. One way that institutions can improve their relationship with constituents is through building genuine partnerships with trusted community figures.

In this randomized phase II clinical trial, we evaluated the effectiveness of adding the TLR agonists, poly-ICLC or resiquimod, to autologous tumor lysate-pulsed dendritic cell (ATL-DC) vaccination in patients with newly-diagnosed or recurrent WHO Grade III-IV malignant gliomas. The primary endpoints were to assess the most effective combination of vaccine and adjuvant in order to enhance the immune potency, along with safety. The combination of ATL-DC vaccination and TLR agonist was safe and found to enhance systemic immune responses, as indicated by increased interferon gene expression and changes in immune cell activation. Specifically, PD-1 expression increases on CD4+ T-cells, while CD38 and CD39 expression are reduced on CD8+ T cells, alongside an increase in monocytes. Poly-ICLC treatment amplifies the induction of interferon-induced genes in monocytes and T lymphocytes. Patients that exhibit higher interferon response gene expression demonstrate prolonged survival and delayed disease progression. These findings suggest that combining ATL-DC with poly-ICLC can induce a polarized interferon response in circulating monocytes and CD8+ T cells, which may represent an important blood biomarker for immunotherapy in this patient population.Trial Registration: ClinicalTrials.gov Identifier: NCT01204684.

BACKGROUND: Equine herpes virus type 1 (EHV-1) infection in horses is associated with respiratory and neurologic disease, abortion, and neonatal death. HYPOTHESIS: Vaccines decrease the occurrence of clinical disease in EHV-1-infected horses. METHODS: A systematic review was performed searching multiple databases to identify relevant studies. Selection criteria were original peer-reviewed research reports that investigated the in vivo use of vaccines for the prevention of disease caused by EHV-1 in domesticated horses. Main outcomes of interest included pyrexia, abortion, neurologic disease, viremia, and nasal shedding. We evaluated risk of bias, conducted exploratory meta-analyses of incidence data for the main outcomes, and performed a GRADE evaluation of the quality of evidence for each vaccine subtype. RESULTS: A total of 1018 unique studies were identified, of which 35 met the inclusion criteria. Experimental studies accounted for 31/35 studies, with the remainder being observational studies. Eight vaccine subclasses were identified including commercial (modified-live, inactivated, mixed) and experimental (modified-live, inactivated, deletion mutant, DNA, recombinant). Risk of bias was generally moderate, often because of underreporting of research methods, and sample sizes were small leading to imprecision in the estimate of the effect size. Several studies reported either no benefit or minimal vaccine efficacy for the primary outcomes of interest. Meta-analyses revealed significant heterogeneity was present, and our confidence in the quality of evidence for most outcomes was low to moderate. CONCLUSIONS AND CLINICAL IMPORTANCE: Our review indicates that commercial and experimental vaccines minimally reduce the incidence of clinical disease associated with EHV-1 infection.

Equine herpesvirus-1 (EHV-1) is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). The previous consensus statement was published in 2009 and considered pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment. A recent survey of American College of Veterinary Internal Medicine large animal diplomates identified the need for a revision to this original consensus statement. This updated consensus statement is underpinned by 4 systematic reviews that addressed key questions concerning vaccination, pharmaceutical treatment, pathogenesis, and diagnostic testing. Evidence for successful vaccination against, or effective treatment of EHV-1 infection was limited, and improvements in experimental design and reporting of results are needed in future studies of this important disease. This consensus statement also updates the topics considered previously in 2009.

BackgroundGiven the waning of vaccine effectiveness and the shifting of the most dominant strains in the U.S., it is imperative to understand the association between vaccination coverage and Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) disease and mortality at the community levels and whether that association might vary according to the dominant SARS-CoV-2 strains in the U.S.MethodsGeneralized estimating equations were used to estimate associations between U.S. county-level cumulative vaccination rates and booster distribution and the daily change in county-wide Coronavirus 2019 disease (COVID-19) risks and mortality during Alpha, Delta and Omicron predominance. Models were adjusted for potential confounders at both county and state level. A 2-week lag and a 4-week lag were introduced to assess vaccination rate impact on incidence and mortality, respectively.ResultsAmong 3,073 counties in 48 states, the average county population complete vaccination rate of all age groups was 50.79% as of March 11th, 2022. Each percentage increase in vaccination rates was associated with reduction of 4% (relative risk (RR) 0.9607 (95% confidence interval (CI): 0.9553, 0.9661)) and 3% (RR 0.9694 (95% CI: 0.9653, 0.9736)) in county-wide COVID-19 cases and mortality, respectively, when Alpha was the dominant variant. The associations between county-level vaccine rates and COVID-19 incidence diminished during the Delta and Omicron predominance. However, each percent increase in people receiving a booster shot was associated with reduction of 6% (RR 0.9356 (95% CI: 0.9235, 0.9479)) and 4% (RR 0.9595 (95% CI: 0.9431, 0.9761)) in COVID-19 incidence and mortality in the community, respectively, during the Omicron predominance.ConclusionsAssociations between complete vaccination rates and COVID-19 incidence and mortality appeared to vary with shifts in the dominant variant, perhaps due to variations in vaccine efficacy by variant or to waning vaccine immunity over time. Vaccine boosters were associated with notable protection against Omicron disease and mortality.

Immune responses to both SARS-CoV-2 infection and its associated vaccines have been highly variable within the general population. The increasing evidence of long-lasting symptoms after resolution of infection, called post-acute sequelae of COVID-19 (PASC) or Long COVID, suggests that immune-mediated mechanisms are at play. Closely related endemic common human coronaviruses (hCoV) can induce pre-existing and potentially cross-reactive immunity, which can then affect primary SARS-CoV-2 infection, as well as vaccination responses. The influence of pre-existing immunity from these hCoVs, as well as responses generated from original CoV2 strains or vaccines on the development of new high-affinity responses to CoV2 antigenic viral variants, needs to be better understood given the need for continuous vaccine adaptation and application in the population. Due in part to thymic involution, normal aging is associated with reduced naïve T cell compartments and impaired primary antigen responsiveness, resulting in a reliance on the pre-existing cross-reactive memory cell pool which may be of lower affinity, restricted in diversity, or of shorter duration. These effects can also be mediated by the presence of down-regulatory anti-idiotype responses which also increase in aging. Given the tremendous heterogeneity of clinical data, utilization of preclinical models offers the greatest ability to assess immune responses under a controlled setting. These models should now involve prior antigen/viral exposure combined with incorporation of modifying factors such as age on immune responses and effects. This will also allow for mechanistic dissection and understanding of the different immune pathways involved in both SARS-CoV-2 pathogen and potential vaccine responses over time and how pre-existing memory responses, including potential anti-idiotype responses, can affect efficacy as well as potential off-target effects in different tissues as well as modeling PASC.

The social and behavioural determinants of COVID-19 vaccination have been described previously. However, little is known about how vaccinated people use and rate their health system. We used surveys conducted in 14 countries to study the health system correlates of COVID-19 vaccination. Country-specific logistic regression models were adjusted for respondent age, education, income, chronic illness, history of COVID-19, urban residence, and minority ethnic, racial, or linguistic group. Estimates were summarised across countries using random effects meta-analysis. Vaccination coverage with at least two or three doses ranged from 29% in India to 85% in Peru. Greater health-care use, having a regular and high-quality provider, and receiving other preventive health services were positively associated with vaccination. Confidence in the health system and government also increased the odds of vaccination. By contrast, having unmet health-care needs or experiencing discrimination or a medical mistake decreased the odds of vaccination. Associations between health system predictors and vaccination tended to be stronger in high-income countries and in countries with the most COVID-19-related deaths. Access to quality health systems might affect vaccine decisions. Building strong primary care systems and ensuring a baseline level of quality that is affordable for all should be central to pandemic preparedness strategies.

BACKGROUND: Dexamethasone is routinely administered to horses but its effect on the antibody response to a commercial EIV/EHV vaccine is unclear. HYPOTHESIS: Horses receiving dexamethasone will have lower postvaccination antibody levels against EIV and EHV-1 than vaccinated controls. ANIMALS: Fifty-five healthy adult research horses. METHODS: Randomized cohort study. Control (no vaccine, group 1), vaccination only (EIV/EHV-1/EHV-4, Prestige 2, Merck Animal Health, group 2), vaccination and concurrent single intravenous dose of dexamethasone (approximately .05 mg/kg, group 3), vaccination and 3 intravenous doses of dexamethasone at 24 hours intervals (group 4). Serum SAA levels were measured on day 1 and day 3. Antibody levels against EIV (hemagglutination inhibition assay, Kentucky 2014 antigen) and EHV-1 (multiplex ELISA targeting total IgG and IgG 4/7) were measured on day 1 and day 30. RESULTS: Significantly increased mean antibody titers after vaccination were only noted against EIV and only after the vaccination alone (n = 14, prevaccine mean [prvm] 166.9, SD 259.6, 95% CI 16.95-316.8; postvaccine mean [povm] 249.1, SD 257.2, 95% confidence interval [CI] 100.6-397.6, P = .02) and the single dose dexamethasone (n = 14, prvm 93.14, SD 72.2, CI 51.45-134.8; povm 185.1, SD 118, CI 116.7-253.6, P = .01), but not after multiple doses of dexamethasone (n = 14, prvm 194.3, SD 258.3, CI 45.16-343.4; povm 240.0, SD 235.7, CI 103.9-376.1, P > .05). CONCLUSION: The effect of dexamethasone on the postvaccine antibody response varies depending on the dosing frequency and the antigen-specific antibody type.

Poliomyelitis (polio) was first targeted for eradication in 1988. Global efforts have led to eradication of 2 of the 3 wild poliovirus (WPV) serotypes (types 2 and 3), and only WPV type 1 (WPV1) remains endemic and only in Afghanistan and Pakistan. This report describes global polio immunization, surveillance activities and poliovirus epidemiology during January 2022-December 2023. Data are current as of 10 April 2024. In 2023, Afghanistan and Pakistan identified 12 WPV1 polio cases, as compared with 22 in 2022. WPV1 transmission was detected by systematic testing for poliovirus in sewage samples (environmental surveillance, ES) in 13 provinces in Afghanistan and Pakistan in 2021 and in 7 in 2022. The number of polio cases caused by circulating vaccine-derived poliovirus (cVDPV) (circulating vaccine virus strains that have reverted to neurovirulence) decreased from 881 in 2022 to 524 in 2023; cVDPV outbreaks (defined as either a cVDPV case with evidence of circulation or at least 2 positive ES isolates) occurred in 32 countries in 2023, including 8 that had not experienced a cVDPV outbreak in 2022. Despite reductions in the number of cases of paralytic polio since 2022, cVDPVs and WPV1 (in countries with endemic transmission) were more widespread in 2023. Renewed efforts to vaccinate children who are persistently missed in countries with endemic WPV1 transmission, strengthening of routine immunization (RI) programmes in high-risk countries and providing more effective cVDPV outbreak response are necessary to achieve further progress towards global polio eradication. L'objectif d'eradiquer la poliomyelite a ete formule pour la premiere fois en 1988. Des efforts a l'echelle mondiale ont conduit a l'eradication de 2 des 3 serotypes (types 2 et 3) de poliovirus sauvage (PVS), et seul le PVS de type 1 (PVS1) demeure endemique dans 2 pays, l'Afghanistan et le Pakistan. Le present rapport decrit la vaccination contre la poliomyelite, les activites de surveillance et l'epidemiologie des poliovirus dans le monde entre janvier 2022 et decembre 2023. Il s'appuie sur des donnees recueillies jusqu'au 10 avril 2024. En 2023, l'Afghanistan et le Pakistan ont identifie 12 cas de PVS1, contre 22 en 2022. La surveillance environnementale, qui consiste a analyser de maniere systematique des echantillons d'eaux usees a la recherche de poliovirus, a detecte une transmission de PVS1 dans 13 provinces d'Afghanistan et du Pakistan en 2021 et dans 7 provinces en 2022. Le nombre de cas de poliomyelite dus aux poliovirus circulants derives d'une souche vaccinale (PVDVc) (souches de virus vaccinaux circulants qui ont retrouve leur neurovirulence) est passe de 881 en 2022 a 524 en 2023; des flambees epidemiques de PVDVc (definies comme un cas de PVDVc associe a une circulation averee du virus ou comme au moins 2 isolats positifs issus de la surveillance environnementale) sont survenues dans 32 pays en 2023, parmi lesquels 8 qui n'avaient pas connu de flambee de PVDVc en 2022. Malgre la reduction du nombre de cas de poliomyelite paralytique depuis 2022, les PVDVc et le PVS1 ont davantage circule en 2023 dans les pays oU la transmission est endemique. Pour continuer a progresser vers l'eradication mondiale de la poliomyelite, il est necessaire de redoubler d'efforts pour vacciner les enfants qui echappent encore a la vaccination dans les pays oU la transmission du PVS1 est endemique, en renforcant les programmes de vaccination systematique dans les pays a haut risque et en assurant une riposte plus efficace aux flambees de PVDVc., Introduction Since establishment of the Global Polio Eradication Initiative (GPEI) in 1988, WPV types 2 and 3 have been eradicated, and WPV1 remains endemic only in Afghanistan and Pakistan. In [...]

Introduction In accordance with its mandate to provide normative guidance to Member States on health policy matters, WHO issues a series of regularly updated position papers on vaccines and combinations [...]

Outbreaks of hepatitis A have been previously reported among gay, bisexual, and other men who have sex with men (MSM) (1). Numerous outbreaks of hepatitis A among MSM were reported [...]