Search

Purpose: The aim of this study is to assess long-term immunogenicity of the recombinant adenoviruses 26 and 5 vector-based COVID-19 vaccine Gam-COVID-Vac (Sputnik V, developed by N. F. Gamaleya National Research Centre, Russia) in patients receiving maintenance hemodialysis (HD) compared to healthy subjects. Materials & methods: A prospective cohort study included patients treated with maintenance HD (n=23) and healthy volunteers (n=28). The levels of anti-severe acute respiratory syndrome coronavirus-2 specific IgG as well as specific T-cell responses were quantified in all participants at two time points: one and six months after complete vaccination. All participates were adults, had been vaccinated twice with Gam-COVID-Vac and had no prior history of confirmed COVID-19. Results: In both groups, IgG levels decreased from month one to six, however, antibodies did not decline more rapidly in HD group (analysis of variance p=0.7214 for the "time×group" interaction, non-adjusted model). At the end of the study, 48.0% of non-HD and 67.0% of HD participants showed T-cell positivity. T-spot counts dropped over time in non-HD controls, but not in HD subjects (p=0.0080 and p=0.1800, respectively). Conclusions: Patients receiving HD maintain significant long-term humoral response after Gam-COVID-Vac vaccination, which is comparable to that in subjects with normal kidney function. Cellular response turned up to be more sustained over time in HD group. [ABSTRACT FROM AUTHOR]

Relevance. On the territory of the Russian Federation, mass vaccination of the population is recognized as a priority health strategy against COVID-19, Gam-COVID-Vac vaccine has been widely used. The main risk group, which is subject to priority vaccination, are employees of medical organizations (MO). The determination of IgG to SARS-CoV-2 is an important parameter for assessing the intensity and duration of post-vaccination immunityAims. Study the immunological efficacy of the vaccine Gam-COVID-Vac used by employees of a psychiatric hospital and a regional hospital.Materials and methods. A study of the blood sera of 410 employees of two MO of various profiles who received one full course of the Gam-COVID-Vac» vaccine for the presence of IgG to RBD Spike SARS-CoV-2 using a set of reagents «SARS-CoV-2-IgG quantitative-ELISA-BEST» and IgG to NC SARS-CoV-2 using a set of reagents «ELISA anti-SARS-CoV-2 IgG».Results and discussion. Specific IgG to RBD Spike SARS-CoV-2 after vaccination with «Gam-COVIDVac » were found in 92.9% of psychiatric hospital staff and 98.0% of the regional hospital. Antibodies of class G to SARS-CoV-2 with a level of 300 BAU/ml or more were detected in 11.6% of psychiatric hospital staff and in 70.0% of regional hospitals, which is associated with the smallest proportion of persons in a psychiatric hospital with hybrid immunity than in a regional hospital (67.4% vs. 89.0%, respectively). A study of employees of the Ministry of Defense of various profiles revealed a difference in the level of IgG to RBD Spike SARS-CoV-2: 178.0 BAU/ml in a psychiatric hospital and 366.0 BAU/ml in a regional hospital. In a psychiatric hospital, the IgG level was highest up to 3 months after the completed vaccination – 166.4 BAU/ml, in a regional hospital from 3 to 6 months – 362.8 BAU/ml, then the number of antibodies decreases, which indicates the importance of monitoring for class G antibodies to SARS-CoV-2 at different times after vaccinations. Among the employees of the two MO, mild forms of the COVID-19 disease prevailed.Conclusion. Thus, the high immunological effectiveness of vaccination against COVID-19 with Gam-COVID-Vac was established in a group of employees of two MO, and the need for serological monitoring for the purpose of revaccination was also shown.

Introduction/Objective. The main aim of this study was to assess COVID-19 vaccination effectiveness (VE) of BBIBP-CorV, Gam-COVID-Vac, BNT162b2, and ChAdOx1-nCoV-19 in Serbia during the first three months of rollout. Methods. The data from the Serbian National Immunization Registry, the Primary Health Centre Report, and the University Clinical Centre Report for Kragujevac, Serbia, for the period from January 1 to March 31, 2021 were used to compare COVID-19 vaccinated population to unvaccinated individuals in terms of laboratory confirmed SARS-CoV-2 infection, COVID-19-related hospitalization and intensive care unit (ICU) admission due to COVID-19. VE was estimated based on the incidence rate ratio, adjusted for age and sex. Results. Overall VE after the first dose reached 20.6%, 28.2%, and 56.1%, and 55.7%, 63.9%, and 79.8%, after the second dose for SARS-CoV-2 infection, COVID-19-related hospitalization, and ICU admission, respectively. BNT162b2 exhibited 96.7% VE against infection and no hospitalization after the second dose. Complete vaccination with BBIBP-CorV and Gam-COVID-Vac demonstrated VE of 43.2% and 78.6% against infection, 56.9% and 85.3% against hospitalization, and 82.3% and 52.7% against ICU admission, respectively. ChAdOx1-nCoV-19 after the first received dose showed VE of 10.3% and 74.7% against infection and hospitalization, with no ICU admission. Conclusion. COVID-19 vaccination in general, as well as each of the four studied vaccines, reduces the risk of SARS-CoV-2 infection, hospitalization due to COVID-19, and COVID-19-related ICU admission. Vaccine effectiveness significantly increases with the second received dose for all study outcomes.

Introduction. In Montenegro, vaccination against COVID-19 infection began with the use of Gam-COVID-Vac, which was not approved for emergency use before the end of clinical trials, by the Food and Drug Administration and the European Medicines Agency. Therefore, it is necessary to emphasize the adverse effects. Materials and methods. For the purpose of this study, there were collected data from national adverse events reporting form for Gam-COVID-Vac obtained from the Health Institution Pharmacy of Montenegro — Montefarm, as the holder of permits for these vaccines. Results. For the period March 1, 2021 to February 13, 2022, after administration of 16 756 doses of vaccine Gam-COVID, a total of 220 case reports, or 716 adverse effects were recorded. The mean age of vaccinated individuals who reported adverse effects was 40.79±11.35 years. Totally, 79.55% females versus 20.45% males reported side effects post-vaccination. The most common adverse reaction was pyrexia (79.55%). Other very common adverse effects were as follows: injection site pain (38.18%), headache (33.18%), myalgia (32.27%), malaise (31.82%), fever (30.45%), arthralgia (22.73%) as well as swelling and redness at the site of application (15.91%). Less common adverse effects were nausea, pain in extremity, diarrhea, dizziness, fatigue, sore throat and labial herpes. Serious adverse effects were recorded in 8 cases including tinnitus, thrombophlebitis, hypotension, chest pain, palpitations and peripheral cyanosis related to specific comorbidities. Conclusions. After the administration of Gam-COVID vaccine, the population in Montenegro experienced mild to moderate adverse effects, with rare serious transient adverse effects related to specific comorbidities. The data presented here on investigating Gam-COVID-Vac caccine verified good safety profile and high tolerability evidenced by the statistics analysis as lacked COVID-19-associated hospitalizations or deaths.

COVID-19 and other infectious diseases can exacerbate the course of paroxysmal nocturnal hemoglobinuria (PNH). The efficacy and safety of the Gam-COVID-Vac vaccine in patients with PNH has not been adequately studied. A retrospective, observational, cohort, non-comparative study was performed to assess the course of COVID-19 as well as the safety and efficacy of the Gam-COVID-Vac (Sputnik V) vaccine in patients with paroxysmal nocturnal hemoglobinuria (PNH). The study included data from 52 patients with PNH aged 18 to 75 years, 38 of whom received background therapy with eculizumab (Elizaria®) between March 2020 and January 2022. COVID-19 was diagnosed according to the results of PCR testing. The patients were divided into two groups for comparison of the incidence of COVID-19. Group 1 included non-vaccinated patients with PNH, and Group 2 included patients vaccinated prior to the onset of COVID-19. According to vaccination, patients were subdivided into non-vaccinated and vaccinated groups without signs of previous COVID-19 at the beginning of the analyzed period, and patients vaccinated half a year or more after recovery from COVID-19. Testing for anti-SARS-CoV-2 IgG levels was carried out in patients with PNH in the year after their COVID-19. Tests for anti-SARS-CoV-2 RBD IgG levels were performed on vaccinated patients. In total, 28 (53.8%) of the enrolled patients had COVID-19, including asymptomatic forms in 7 (25%) and mild forms in 16 (57%) patients. A total of 22 (42.3%) patients were fully vaccinated with Gam-COVID-Vac, of which 13 (25%) patients were vaccinated without the signs of previous SARS-CoV-2infection, and 9 (17.3%) patients were vaccinated after COVID-19. The number of patients who had COVID-19 was about two times higher in Group 1 (non-vaccinated; 24) (61.5%), whereas in Group 2 (vaccinated), the number of patients with COVID-19 was only 4 (30.8%). The proportion and number of patients who did not have COVID-19 was higher in the group of vaccinated patients (9; 69.2%) than in the group of non-vaccinated patients (15; 38.5%) (p = 0.054). In patients who had been infected with COVID-19, maximum concentrations of anti-SARS-CoV-2 IgG were observed 2–3 months after the acute infection phase, followed by a gradual decline by month 9–10. The mean RBD IgG concentration was higher in the group of patients who had been infected by COVID-19 than in the group of patients without COVID-19 (p = 0.047). Therapy type, including eculizumab, did not have a significant impact on RBD IgG titers (p > 0.05). Hospitalization was required in five (18%) patients, all of whom had breakthrough hemolysis and severe lung damage on CT scans. After the first dose, adverse events (AEs) were reported in 41% of the patients (body temperature increased in 18%; headache in 13.6%; and pain in joints in 4.5%; colitis exacerbation was observed in 4.5%). After the second dose, no AEs were reported. The performed study suggests the possible efficacy and demonstrates the safety of Gam-COVID-Vac (Sputnik V) for the prophylaxis of COVID-19 in patients with PNH who experience immunosuppression due to target therapy.

The aim of the study was to assess the safety of the combined vector vaccine Gam-COVID-Vac (Sputnik V) and to determine the risk factors for the development of adverse events in patients with immuno-inflammatory rheumatic diseases (IIRD). Patients and methods. A single-stage study of patients with IIRD who were on inpatient treatment or who applied to the consultative and diagnostic center of the V.A. Nasonova Research Institute of Rheumatology was conducted, who received both components of the Sputnik V vaccine. The control group included immunized persons without IIRD. All participants were interviewed by a research doctor with filling out a unified questionnaire, additional information was obtained from medical documentation. Results. The study included 325 patients with IIRD and 138 healthy controls. After vaccination with the first component, the number of patients with IIRD, in whom the development of local and systemic adverse events (AEs) was noted, was significantly lower compared to the control (20.3% and 38.4% respectively; p

Objectives: The aim is to study impact of vaccination against the novel coronavirus disease (COVID-19) with Sputnik V on mortality during the period of predominance of the delta variant of SARS-CoV-2. Methods: This was a retrospective cohort study of individuals with state health insurance at the Moscow Ambulatory Center. The cohorts included 41,444 persons vaccinated with Sputnik V, 15,566 survivors of COVID-19, and 71,377 non-immune persons. The deaths of patients that occurred from June 1, 2021, to August 31, 2021, were analyzed. Results: Overall (0.39 % vs. 1.92 %; p 85 years. Conclusion: COVID-19 vaccination with Sputnik V is associated with a decrease in overall and COVID-19-related mortality and is not with increased non-COVID mortality.

The article discusses the effectiveness and safety of homologous and heterologous revaccination for Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in people of different age groups.Aim. The study the severity and duration of immune response in people of different age groups after SARS-CoV-2 revaccination.Material and methods. The study was carried out as part of the prospective registry Saturn, which included persons who received various SARS-CoV-2 revaccination regimens (homoand heterologous) based on the combination of two vaccines: Gam-COVID-Vac and Covivac. Group I (n=106) included persons who received a homologous revaccination with Gam-COVID-Vac, while group II (n=54) — heterologous revaccination with Gam-COVID-Vac and Covivac, group III (n=40) — homologous Covivac revaccination. In addition, all participants in the study were divided into two age categories: ≥60 years (n=33) and

COVID-19 and other infectious diseases can exacerbate the course of paroxysmal nocturnal hemoglobinuria (PNH). The efficacy and safety of the Gam-COVID-Vac vaccine in patients with PNH has not been adequately studied. A retrospective, observational, cohort, non-comparative study was performed to assess the course of COVID-19 as well as the safety and efficacy of the Gam-COVID-Vac (Sputnik V) vaccine in patients with paroxysmal nocturnal hemoglobinuria (PNH). The study included data from 52 patients with PNH aged 18 to 75 years, 38 of whom received background therapy with eculizumab (Elizaria®) between March 2020 and January 2022. COVID-19 was diagnosed according to the results of PCR testing. The patients were divided into two groups for comparison of the incidence of COVID-19. Group 1 included non-vaccinated patients with PNH, and Group 2 included patients vaccinated prior to the onset of COVID-19. According to vaccination, patients were subdivided into non-vaccinated and vaccinated groups without signs of previous COVID-19 at the beginning of the analyzed period, and patients vaccinated half a year or more after recovery from COVID-19. Testing for anti-SARS-CoV-2 IgG levels was carried out in patients with PNH in the year after their COVID-19. Tests for anti-SARS-CoV-2 RBD IgG levels were performed on vaccinated patients. In total, 28 (53.8%) of the enrolled patients had COVID-19, including asymptomatic forms in 7 (25%) and mild forms in 16 (57%) patients. A total of 22 (42.3%) patients were fully vaccinated with Gam-COVID-Vac, of which 13 (25%) patients were vaccinated without the signs of previous SARS-CoV-2infection, and 9 (17.3%) patients were vaccinated after COVID-19. The number of patients who had COVID-19 was about two times higher in Group 1 (non-vaccinated; 24) (61.5%), whereas in Group 2 (vaccinated), the number of patients with COVID-19 was only 4 (30.8%). The proportion and number of patients who did not have COVID-19 was higher in the group of vaccinated patients (9; 69.2%) than in the group of non-vaccinated patients (15; 38.5%) (p = 0.054). In patients who had been infected with COVID-19, maximum concentrations of anti-SARSCoV-2 IgG were observed 2–3 months after the acute infection phase, followed by a gradual decline by month 9–10. The mean RBD IgG concentration was higher in the group of patients who had been infected by COVID-19 than in the group of patients without COVID-19 (p = 0.047). Therapy type, including eculizumab, did not have a significant impact on RBD IgG titers (p > 0.05). Hospitalization was required in five (18%) patients, all of whom had breakthrough hemolysis and severe lung damage on CT scans. After the first dose, adverse events (AEs) were reported in 41% of the patients (body temperature increased in 18%; headache in 13.6%; and pain in joints in 4.5%; colitis exacerbation was observed in 4.5%). After the second dose, no AEs were reported. The performed study suggests the possible efficacy and demonstrates the safety of Gam-COVID-Vac (Sputnik V) for the prophylaxis of COVID-19 in patients with PNH who experience immunosuppression due to target therapy. [ABSTRACT FROM AUTHOR]

To protect young individuals against SARS-CoV-2 infection, we conducted an open-label, prospective, non-randomised dose-escalation Phase 1/2 clinical trial to evaluate the immunogenicity and safety of the prime-boost "Sputnik V" vaccine administered at 1/10 and 1/5 doses to adolescents aged 12-17 years. The study began with the vaccination of the older cohort (15-to-17-year-old participants) with the lower (1/10) dose of vaccine and then expanded to the whole group (12-to-17-year-old participants). Next, 1/5 dose was used according to the same scheme. Both doses were well tolerated by all age groups. No serious or severe adverse events were detected. Most of the solicited adverse reactions were mild. No significant differences in total frequencies of adverse events were registered between low and high doses in age-pooled groups (69.6% versus 66.7%). In contrast, the 1/5 dose induced significantly higher humoral and T cell-mediated immune responses than the 1/10 dose. The 1/5 vaccine dose elicited higher antigen-binding (both S and RBD-specific) as well as virus-neutralising antibody titres at the maximum of response (day 42), also resulting in a statistically significant difference at a distanced timepoint (day 180) compared to the 1/10 vaccine dose. Higher dose resulted in increased crossneutralization of Delta and Omicron variants. [ABSTRACT FROM AUTHOR]

Background: Measuring the level of antibodies produced post-vaccination in response to the SARS-CoV-2 spike protein is considered a strategy for estimating the effectiveness of the COVID-19 vaccines.Objective: To examine the antibody levels among the healthcare workers in different hospitals in Mashhad, Iran after receiving the second dose of Sputnik V.Methods: In this study, we enrolled 230 healthcare workers for evaluating the Gam-COVID-Vac or Sputnik V after the second administration in different hospitals in Mashhad. Antibody levels of spike protein were quantitatively evaluated in a sample of 230 negative RT-PCR tests for the COVID-19 individuals. The analysis has been done based on an immunological assay using enzyme-linked immunosorbent assay (ELISA). The infection history of the subjects and their families was examined through their medical records.Results: Our results demonstrated a significant association between a higher titer of IgG and a previous history of the COVID-19 infection (P

To protect young individuals against SARS-CoV-2 infection, we conducted an open-label, prospective, non-randomised dose-escalation Phase 1/2 clinical trial to evaluate the immunogenicity and safety of the prime-boost “Sputnik V” vaccine administered at 1/10 and 1/5 doses to adolescents aged 12–17 years. The study began with the vaccination of the older cohort (15-to-17-year-old participants) with the lower (1/10) dose of vaccine and then expanded to the whole group (12-to-17-year-old participants). Next, 1/5 dose was used according to the same scheme. Both doses were well tolerated by all age groups. No serious or severe adverse events were detected. Most of the solicited adverse reactions were mild. No significant differences in total frequencies of adverse events were registered between low and high doses in age-pooled groups (69.6% versus 66.7%). In contrast, the 1/5 dose induced significantly higher humoral and T cell-mediated immune responses than the 1/10 dose. The 1/5 vaccine dose elicited higher antigen-binding (both S and RBD-specific) as well as virus-neutralising antibody titres at the maximum of response (day 42), also resulting in a statistically significant difference at a distanced timepoint (day 180) compared to the 1/10 vaccine dose. Higher dose resulted in increased cross-neutralization of Delta and Omicron variants.;Clinical Trial RegistrationClinicalTrials.gov, NCT04954092, LP-007632.

The aim is to study impact of vaccination against the novel coronavirus disease (COVID-19) with Sputnik V on mortality during the period of predominance of the delta variant of SARS-CoV-2. This was a retrospective cohort study of individuals with state health insurance at the Moscow Ambulatory Center. The cohorts included 41,444 persons vaccinated with Sputnik V, 15,566 survivors of COVID-19, and 71,377 non-immune persons. The deaths of patients that occurred from June 1, 2021, to August 31, 2021, were analyzed. Overall (0.39 % vs. 1.92 %; p < 0.001), COVID-19-related (0.06 % vs. 0.83 %; p < 0.001), and non-COVID mortality (0.33 % vs. 1.09 %; p < 0.001) was lower among vaccinated individuals than among non-immune individuals. The efficacy of vaccination against death from COVID-19 was 96 % [95 % CI 91–98 %] in the general population, 100 % among those aged 18–50 years, 97 % [95 % CI 76–100 %] among those aged 51–70 years, 98 % [95 % CI 90–100 %] among those aged 71–85 years, and 88 % [95 % CI 49–97 %] among those aged > 85 years. COVID-19 vaccination with Sputnik V is associated with a decrease in overall and COVID-19-related mortality and is not with increased non-COVID mortality. • The overall mortality was lower among the vaccinated persons than among the non-immune ones. • The overall mortality was lower among the vaccinated persons than in post- COVID group. • There was no difference in COVID-19 related mortality between post-COVID and vaccinated groups. [ABSTRACT FROM AUTHOR]

Introduction/Objective. The duration of vaccine-induced protection against SARS-CoV-2 is shown to be limited. The aim of this study was to assess vaccine effectiveness (VE) of a third dose of four different COVID-19 vaccines during Delta variant predominance in Serbia. Methods. The data for the period from August 18, to October 1, 2021 were used to estimate the incidence rates (IR) of the SARS-CoV-2 infection, COVID-19-related hospitalization, and intensive care unit (ICU) admission. The study included 41,186 fully vaccinated subjects, of which 13,589 had received the third dose. VE was estimated based on the IR ratio following vaccination with three vs. two doses. Results. We found that a third dose of all investigated vaccines reduces the incidence of both SARS-CoV-2 infection and severe illness that requires hospitalization or ICU admission. The highest VE against infection demonstrated BNT162b2, followed by Gam-COVID-Vac and BBIBP-CorV. Third dose vaccination reduced the risk of hospitalization (IR = 0 for Gam-COVID-Vac and BBIBP-CorV), and ICU admission (IR = 0 for all vaccines). The hazard distributions for SARS-CoV-2 infection and hospitalization following vaccination with three versus two doses were significantly different. Conclusion. These findings indicate that an additional, third dose of studied vaccine boosters protection against all investigated outcomes.

The clinical case describes the difficulties of differential diagnosis of polyneuropathy that developed after Gam-Covid-Vac vaccination on the background of combined infectious pathology (HIV infection, tick-borne borreliosis, COVID-19) in a young woman. It is shown that various infectious and non-infectious diseases with similar clinical symptoms (peripheral nervous system affliction) occurring simultaneously in one patient can significantly affect each other’s course and complicate the establishment of the true cause of polyneuropathy. It should be noted that in this example, the establishment of a final diagnosis was carried out collectively, by consensus, and was based on the effectiveness of etiotropic (antibacterial) treatment, which in fact was an ex juvantibus therapy option, which made it possible to establish the most probable etiology of polyneuropathy – tick-borne borreliosis. In turn, HIV infection and possibly vaccination, according to the authors, could cause immunosuppression, which affected the degree of dissemination of Borrelia burgdorferi. It is also likely that the insufficient immune response in combination with the cascade plasma filtration session affected the initial dubious results of the serological tests, which further complicated the diagnosis.

Abstract Since its initial detection in Brazil in February 2020, SARS-CoV-2 and the associated COVID-19 pandemic have continued to devastate Latin America. Specific comorbidities, as well as sociodemographic and lifestyle factors that may be more prevalent in underserved areas, have been identified as risk factors for COVID-19 infection or associated adverse outcomes. Dynamics of infections and deaths in Latin America have varied by country and temporally, as has SARS-CoV-2 variant prevalence; however, more recently, the Delta and subsequent Omicron variants have become ubiquitous. Successful pandemic responses have involved robust infection mitigation measures, testing, and smart deployment of healthcare resourcing. While in some Latin American countries up to 90% of the population is fully vaccinated (i.e., 2 doses) against COVID-19, other countries have failed to reach the World Health Organization’s 70% target. Continued focus on comprehensive surveillance, strategies to maximize vaccine availability and uptake, and mitigation of collateral damage on other aspects of public health and social services are critical for managing the COVID-19 pandemic. This review summarizes the COVID-19 experience in Latin America, including epidemiology and vaccination. Key learnings and future considerations for the ongoing pandemic response are also discussed.

Currently, as the SARS-CoV-2 pandemic evolves, there has been increasingly more attention paid to building natural and vaccine-induced immunity against SARS-CoV-2 and related disease known as COVID-19. Widespread preventive vaccination plays an important role in effectively protecting people from viral infections and can reduce national economic costs. Purpose to study peripheral blood cell subset composition and magnitude of humoral response in vaccinated Gam-COVID-Vac subjects. The prospective study included 352 patients, of which 194 (119 women and 75 men) underwent an immunogram study and assessed level of anti-SARS-CoV-2 antibodies. In patients, the study of the lymphocyte subset composition and estimation of anti-SARS-CoV-2 antibodies was carried out at two time points prior to vaccination and 90 days after inoculated component 1 of the Gam-COVID-Vac vaccine. In general, vaccination was well tolerated by patients, with no serious adverse events after immunization. The reaction to the vaccine (fever, malaise, headache, local reactions) was short-term (12 days) and more often noted after inoculated vaccine component 2. Comparatively analyzed immunogram parameters in females before and after vaccination revealed increased relative level of T-lymphocytes (CD3+), T-helper cell subset (CD3+CD4+), increased absolute and relative level of activated CD3+CD25+ T-lymphocytes, but decreased absolute and relative level of natural killer (CD3CD56+CD16+) and natural killer T-cell (CD3+CD56+CD16+) cell subsets as well as decreased CD147 receptor expression on T-lymphocytes. Similar patterns were also found while examining the immunogram in males exepting increased level of lymphocytes and lowered CD147 expression on both T- and B-lymphocytes. No changes in the parameters of the immune T-cell arm was found. The high efficacy of the vaccine was confirmed by development of SARS-CoV-2-specific class G antiviral antibodies in 97.5% and 92.3% of vaccinated females and males, respectively. The data obtained evidence that: 1) vaccination induces a specific humoral immune response determined three months post-vaccination, and 2) it caused no serious disturbances in the immune system functioning, which could be reflected in the peripheral blood lymphocyte subset composition. Thus, the data presented allow to conclude that Gam-COVID-Vac is effective vaccine against SARS-CoV-2 infection.

In November 2020, the Armed Forces of the Russian Federation began mass immunisation of the personnel with Gam-COVID-Vac (Sputnik V), the first Russia vaccine against the new coronavirus infection (COVID-19). Thus, it became necessary to assess post-vaccination antibody levels and the duration and intensity of humoral immunity to COVID-19.The aim of the study was to investigate the immunogenicity and efficacy of Gam-COVID-Vac in military medical staff after vaccination.Materials and methods: the authors determined the presence of specific antibodies in the serum of individuals immunised with Gam-COVID-Vac (477 volunteers) and COVID-19 convalescents (73 patients), using virus neutralisation (VN), enzyme-linked immunosorbent assay (ELISA) with reagent kits by several manufacturers, and immunoblotting. The results of the study were evaluated using analysis of variance.Results: VN detected virus neutralising antibodies in 90.7% of vaccinated subjects; ELISA, in 95.4%. Both VN and ELISA showed lower antibody levels in the vaccinated over 50 years of age. ELISA demonstrated a significantly higher concentration of anti-SARS-CoV-2 spike IgG in the Gam-COVID-Vac group than in the COVID-19 convalescent group. The correlation between antibody detection results by VN and ELISA was the strongest when the authors used their experimental reagent kit for quantitative detection of virus neutralising antibodies by competitive ELISA with the recombinant human ACE2 receptor. Having analysed the time course of neutralising antibody titres, the authors noted a significant, more than two-fold decrease in geometric means of the titres three months after administration of the second vaccine component.Conclusions: the subjects vaccinated with Gam-COVID-Vac gain effective humoral immunity to COVID-19. The decrease in titres indicates the need for revaccination in 6 months.

Although unprecedented efforts aiming to stop the COVID-19 pandemic have been made over the past two years, SARSCoV-2 virus still continues to cause intolerable health and economical losses. Vaccines are considered the most effective way to prevent infectious diseases, which has been reaffirmed for COVID-19. However, in the context of the continuing virus spread because of insufficient vaccination coverage and emergence of new variants of concern, there is a high demand for vaccination strategy amendment. The ability to elicit protective immunity at the entry gates of infection provided by mucosal vaccination is key to block virus infection and transmission. Therefore, these mucosal vaccines are believed to be a “silver bullet” that could bring the pandemic to an end. Here, we demonstrate that the intranasally delivered Gam-COVID-Vac (Sputnik V) vaccine induced a robust (no less than 180 days) systemic and local immune response in mice. High immunogenic properties of the vaccine were verified in non-human primates (common marmosets) by marked IgG and neutralizing antibody (NtAb) production in blood serum, antigen-specific Tcell proliferation and cytokine release of peripheral blood mononuclear cells accompanied by formation of IgA antibodies in the nasal mucosa. We also demonstrate that Sputnik V vaccine can provide sterilizing immunity in K18-hACE2 transgenic mice exposed to experimental lethal SARS-CoV-2 infection protecting them against severe lung immunopathology and mortality. We believe that intranasal Sputnik V vaccine is a promising novel needle-free mucosal vaccine candidate for primary immunization as well as for revaccination and is worth further clinical investigation.

Millions of people have been vaccinated with Gam-COVID-Vac but fine specificities of induced antibodies have not been fully studied. Plasma from 12 naïve and 10 coronavirus disease 2019 (COVID-19) convalescent subjects was obtained before and after two immunizations with Gam-COVID-Vac. Antibody reactivity in the plasma samples (n = 44) was studied on a panel of micro-arrayed recombinant folded and unfolded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins and 46 peptides spanning the spike protein (S) and by immunoglobulin G (IgG) subclass enzyme-linked immunosorbent assay (ELISA). The ability of Gam-COVID-Vac-induced antibodies to inhibit binding of the receptor-binding domain (RBD) to its receptor angiotensin converting enzyme 2 (ACE2) was investigated in a molecular interaction assay (MIA). The virus-neutralizing capacity of antibodies was studied by the pseudo-typed virus neutralization test (pVNT) for Wuhan-Hu-1 and Omicron. We found that Gam-COVID-Vac vaccination induced significant increases of IgG1 but not of other IgG subclasses against folded S, spike protein subunit 1 (S1), spike protein subunit 2 (S2), and RBD in a comparable manner in naïve and convalescent subjects. Virus neutralization was highly correlated with vaccination-induced antibodies specific for folded RBD and a novel peptide (i.e., peptide 12). Peptide 12 was located close to RBD in the N-terminal part of S1 and may potentially be involved in the transition of the pre- to post-fusion conformation of the spike protein. In summary, Gam-COVID-Vac vaccination induced S-specific IgG1 antibodies in naive and convalescent subjects in a comparable manner. Besides the antibodies specific for RBD, the antibodies induced against a peptide close to the N-terminus of RBD were also associated with virus-neutralization. [ABSTRACT FROM AUTHOR]

The course of the COVID-19 pandemic has been critically altered by the availability of vaccines. To assess the risk of COVID-19 in the vaccinated, as compared to the unvaccinated population, as well as the comparative effectiveness of the BBIBP-CorV (Sinopharm), BNT162b2 (Pfizer/BioNTech), Gam-COVID-Vac (Sputnik V) and ChAdOx1 (AstraZeneca) vaccines in the prevention of clinical infection, we carried out a retrospective study of the incidence of clinical COVID-19 in the Belgrade city municipality of Voždovac among both vaccinated and unvaccinated individuals during a 4-month period between 1 July and 31 October 2021. The study included all individuals with a symptomatic infection confirmed by a positive PCR and/or antigen test. Only those who received two vaccine doses were considered as vaccinated. The results showed that of the Voždovac population of 169,567, a total of 81,447 (48%) individuals were vaccinated by the end of the study. Vaccination coverage increased with age, ranging from 1.06% in those below age 18, to even 78.8% in those above 65 years of age. More than one half (57.5%) of all those vaccinated received BBIBP-CorV, while 25.2% received BNT162b2, 11.7% Gam-COVID-Vac and 5.6% ChAdOx1. The overall risk of infection of the vaccinated vs. the unvaccinated was 0.53 (95% CI 0.45–0.61). Compared to the incidence of COVID-19 of 8.05 per 1000 in the unvaccinated population, the relative risk in the vaccinated was 0.35 (95% CI 0.3–0.41). The overall VE was 65%, differing widely among age groups and by vaccine. VE was 79% for BNT162b2, 62% for BBIBP-CorV, 60% for ChAdOx1 and 54% for Gam-COVID-Vac. The VE for BBIBP-CorV and BNT162b2 increased with age. The obtained results demonstrate a significant overall effectiveness of anti-COVID-19 vaccination, which, however, varied significantly among the analyzed vaccines, and was the highest for BNT162b2. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has required extensive research on the new coronavirus SARS-CoV-2 and the creation of new highly effective vaccines. The presence of T-cells in the body that respond to virus antigens suggests adequate antiviral immunity. We investigated T-cell immunity in individuals who recovered from mild and moderate COVID-19 and in individuals vaccinated with the Gam-COVID-Vac combined vector vaccine. The ELISPOT method was used to determine the number of T-cells responding with IFN-γ synthesis to stimulation by peptides containing epitopes of the S-protein or N-, M-, ORF3, and ORF7 proteins, using peripheral blood mononuclear cells (PBMCs). At the same time, the multiplex method was used to determine the accumulation of IFN-γ and other cytokines in the culture medium. According to the data obtained, the proportion of positive conclusions about the T-cell immune response to SARS-CoV-2 antigens in control, recovered, and vaccinated individuals was 12%, 70%, and 52%, respectively. At the same time, more than half of the vaccinated individuals with a T-cell response were sensitized to the antigens of N-, M-, ORF3, and ORF7 proteins not produced by Gam-COVID-Vac, indicating a high likelihood of asymptomatic SARS-CoV-2 infection. Increased IFN-γ release by single sensitized T-cells in response to specific stimulation in recovered and vaccinated individuals did not result in the accumulation of this and other cytokines in the culture medium. These findings suggest a balance between cytokine production and utilization by immunocompetent cells as a prerequisite for providing a controlled cytokine signal and avoiding a "cytokine storm". [ABSTRACT FROM AUTHOR]

Since its initial detection in Brazil in February 2020, SARS-CoV-2 and the associated COVID-19 pandemic have continued to devastate Latin America. Specific comorbidities, as well as sociodemographic and lifestyle factors that may be more prevalent in underserved areas, have been identified as risk factors for COVID-19 infection or associated adverse outcomes. Dynamics of infections and deaths in Latin America have varied by country and temporally, as has SARS-CoV-2 variant prevalence; however, more recently, the Delta and subsequent Omicron variants have become ubiquitous. Successful pandemic responses have involved robust infection mitigation measures, testing, and smart deployment of healthcare resourcing. While in some Latin American countries up to 90% of the population is fully vaccinated (i.e., 2 doses) against COVID-19, other countries have failed to reach the World Health Organization's 70% target. Continued focus on comprehensive surveillance, strategies to maximize vaccine availability and uptake, and mitigation of collateral damage on other aspects of public health and social services are critical for managing the COVID-19 pandemic. This review summarizes the COVID-19 experience in Latin America, including epidemiology and vaccination. Key learnings and future considerations for the ongoing pandemic response are also discussed. [ABSTRACT FROM AUTHOR]

Background. Students, as the most active and mobile part of population, often unite into educational and informal groups, move to other regions or countries, and present a specific risk group for the spread of new coronavirus infection. Thus, they require preventive vaccination. objective. The aim of the study is to study the immunological potency, tolerance, and efficacy of Gam-COVID-Vac vaccine among students of Krasnodar. Methods. 119 seronegative students (18-30 years old) were examined. SARS-CoV-2 IgG (ELISA method) was determined 1, 3, and 6 months after two completed rounds of vaccination. Post-vaccination adverse events and COVID-19 cases were evaluated in the study. Results. SARS-CoV-2 IgG level 1 month after vaccination ranged from 6.15 to 19.38 and was to 16.39 (AU/mL) ± 1,12. Immunological potency values ranged from 4.407 to 21.5 (AU/mL) (14.74 ± 2.93) 3 months after. IgG titers were in the range of 4.14 to 17.71 (AU/mL) (10.97 ± 4.69) 6 months after. Adverse events after vaccination were revealed in 34 respondents (28.6%). Among them, local (hyperemia, pain, edema) — 21 (17.6%): slight — 90.4%, major — 9.6%; general (fever, weakness, algor, headache, arthralgia, myalgia) — 13 (10.9%): slight — 69.2%, major — 30.8%. The increase in vaccination coverage in students from 30.3 to 79.1% reduced the COVID-19 morbidity from 3.81 to 1.57%. Conclusion. Gam-COVID-Vac vaccine induced stable humoral response, demonstrated sufficient safety, and reduced morbidity 2.4-fold.

• Data about COVID-19 vaccine antibody response in the real-world are provided. • Combined vaccination induces the highest antibody level. • A boost dose benefits still previously infected volunteers. • Neutralising antibodies maintained over time after vaccination with any vaccines. Although there has developed an increased interest in the vaccines BNT1622b2 (Pfizer/BioNTech), mRNA-1273 (Moderna/NIAID), and ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford), there are still few reports describing the immune response induced by different vaccine platforms in real-world settings of low-income countries. Here, we proposed to analyse the humoral immune response elicited by the primary vaccines used in Argentina from July-December 2021. Anti-SARS-CoV-2-Spike-RBD IgG and neutralising antibodies were assayed by ELISA in a total of 871 serum samples obtained from 376 volunteers from an educational staff. The individuals were vaccinated with BBIBP-CorV (Sinopharm), ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford, AZ), Gam-COVID-Vac (Sputnik V, SpV) or combined vaccines (mostly SpV and mRNA-1273, Moderna). The antibody response was analysed several days after the initial vaccination (20, 40, 120 and 180 days). After receiving at least one dose of the COVID-19 vaccine, we detected 93.34% of seroprevalence. Previously SARS-CoV-2 infected showed higher antibody concentrations compared with naïve vaccinees. Six months after the initial vaccination, combined vaccination induced higher anti-SARS-CoV-2 antibody levels than the other vaccines in naïve volunteers. However, we did not find differences in the neutralising responses after any vaccine from naïve vaccines or between the naïve and previously infected volunteers on day 120 after vaccination. Our long-term analysis of volunteers from the educational system provides data in a real-world context, showing the benefits of a boost dose still in previously infected volunteers, and suggesting the advantages of a heterologous prime-boost schedule. [ABSTRACT FROM AUTHOR]

Vaccination against COVID-19 has occurred in Russia for more than two years. According to the Russian official clinical guidelines to maintain tense immunity in the conditions of the ongoing COVID-19 pandemic, it is necessary to use booster immunization six months after primary vaccination or a previous COVID-19 contraction. It is especially important to ensure the maintenance of protective immunity in the elderly, who are at risk of severe courses of COVID-19. Meanwhile, the immunological effectiveness of the booster doses has not been sufficiently substantiated. To investigate the immunogenicity of Sputnik V within the recommended revaccination regimen and evaluate the effectiveness of booster doses, we conducted this study on 3983 samples obtained from individuals previously vaccinated with Sputnik V in Moscow. We analyzed the level of antibodies in BAU/mL three times: (i) six months after primary immunization immediately before the booster (RV), (ii) 3 weeks after the introduction of the first component of the booster (RV1), and (iii) 3 weeks after the introduction of the second component of the booster (RV2). Six months after the primary vaccination with Sputnik V, 95.5% of patients maintained a positive level of IgG antibodies to the receptor-binding domain (RBD) of SARS-CoV-2. The degree of increase in the specific virus-neutralizing antibodies level after revaccination increased with a decrease in their initial level just before the booster dose application. In the group of people with the level of antibodies up to 100 BAU/mL six months after the vaccination, a more than eightfold increase (p < 0.001, Wilcoxon criterion with Bonferroni adjustment) in the level of specific antibodies was observed (Me = 8.84 (IQR: 3.63–30.61)). A significant increase in the IgG level after receiving both the first and the second booster doses occurred at the initial titer level up to 300 BAU/ mL (p < 0.001) in those who did not contract COVID-19 in the past and up to 100 BAU/mL (p < 0.001) in those who were previously infected with SARS-CoV-2. A significant increase in the antibody level after the first dose of the booster was noted for people who had up to 500 BAU/mL (p < 0.05), regardless of the previous COVID-19 infection. Thus, revaccination is most effective in individuals with an antibody level below 500 BAU/mL, regardless of the vaccinee age and COVID-19 contraction. For the first time, it has been shown that a single booster dose of the Sputnik vaccine is sufficient to form a protective immunity in most vaccinees regardless of age and preexisting antibody level. [ABSTRACT FROM AUTHOR]

Many available SARS-CoV-2 vaccines demonstrated good humoral response, but studies directly comparing their immunogenicity in the general population are lacking. We evaluated the medium–term kinetics of anti-S SARS-CoV-2 antibodies (Abs) at one and six months after the second dose of BNT162b2, BBIBP-CorV, and Gam-COVID-Vac. Immunogenicity at six months was directly compared between BNT162b2, BBIBP-CorV, Gam-COVID-Vac, and ChAdOx1 nCoV-19. Participants ≥ 20 years old from Novi Sad, Serbia, without prior SARS-CoV-2 infection, were included. Anti S1/S2 IgG antibodies were measured using quantitative LIAISON SARS-CoV-2 assay. A total of 368 participants were included: 231 (62.77%) had sera collected at two time points. Two doses of BNT162b2 were received by 37.50% of participants, followed by BBIBP-CorV (22.01%), Gam-COVID-Vac (21.47%), and ChAdOx1 nCoV-19 (19.02%). Mean Ab levels at the 28th day and 6 months were 216.55 (SD = 105.73) AU/mL and 75.68 (SD = 57.30) for BNT162b2, 194.38 (SD = 140.24) and 90.53 (SD = 111.30) for Gam-COVID-Vac, and 72.74 (SD = 80.04) and 24.43 (SD = 38.43) for BBIBP-CorV group (p < 0.01, between two time points across all three groups), with a significant difference between women and men (p < 0.01, for both sexes). At the sixth month post-vaccination, the highest mean Ab level was detected in Gam-COVID-Vac group (91.28 AU/mL, SD = 95.96), followed by BNT162b2 (85.25 AU/mL, SD = 60.02), ChAdOx1 nCoV-19 (64.22 AU/mL, SD = 65.30), and BBIBP-CorV (25.26 AU/mL, SD = 36.92) (p < 0.01). Anti-spike IgG persistence was demonstrated six months post-vaccination with a significant decline in Ab levels. These results suggest a lower protection against SARS-CoV-2 over time. Our findings support the introduction of additional (booster) doses. [ABSTRACT FROM AUTHOR]

Abstract SARS‐CoV‐2 vaccines provide a safe solution with a major impact on reducing the spread of the virus and mild side effects. Research has shown rare cases of myocarditis after mRNA vaccines. This study presents a 29‐year‐old male with chest pain after 48 h of receiving rAd26 and rAd5 vector‐based COVID‐19 vaccine (Sputnik V vaccine). The electrocardiogram revealed ST‐segment elevation. Also, the laboratory screening was remarkable for elevated cardiac Troponin‐I level, and leukocytosis; and echocardiography depicted severe left ventricular systolic dysfunction. Overall, endomyocardial biopsy proved lymphocytic myocarditis such that the patient was successfully treated with immunosuppressive and guideline‐directed medical treatment.

To compare the homologous prime-boost vaccination scheme of Gam-COVID-Vac (Sputnik V (SpV)) to its heterologous combination with mRNA-1273 (Moderna (Mod)) vaccine. SARS-CoV-2 anti-spike (S)-receptor binding domain (RBD) IgG concentration was assessed three to seven weeks after complete vaccination. Reactogenicity was evaluated by declared side events and medical assistance required until day 7 post boost. Of 190 participants enrolled, 105 received homologous SpV/SpV and the remaining heterologous SpV/Mod vaccination scheme, respectively. Median (interquartile range (IQR)) age was 54 (37–63) years, 132 out of 190 (69.5%) were female, and 46 out of 190 (24.2%) individuals had a prior confirmed COVID-19. Anti-S-RBD IgG median (IQR) titers were significantly higher for SpV/Mod (2511 (1476–3992) binding antibody units (BAU)/mL) than for SpV/SpV (582 (209–1609) BAU/mL; p < 0.001] vaccination scheme. In a linear model adjusted for age, gender, time to the serological assay, and time between doses, SpV/Mod (4.154 (6.585–615.554); p < 0.001] and prior COVID (3.732 (8.641–202.010); p < 0.001) were independently associated with higher anti-S-RBD IgG values. A higher frequency of mild and moderate adverse effects was associated with the heterologous scheme (20 of 85 (23.5%) vs. 13 of 105 (12.4%); p = 0.043 and 27 of 85 (31.8%) vs. 14 of 105 (13.3%); p = 0.002), respectively, although it was well tolerated by all individuals and no medical assistance was required. The heterologous SpV/Mod combination against SARS-CoV-2 is well tolerated and significantly increases humoral immune response as compared to the homologous SpV/SpV immunization. [ABSTRACT FROM AUTHOR]

IgM and IgG antibodies to the SARS-CoV-2 virus are detected in subjects who have recovered from COVID-19; IgM antibodies persist in a 1/3 of infected subjects up to 12 months from the moment of the disease, while IgG antibodies are present in the vast majority of cases (97%; medium and high levels antibodies were registered in 85% of cases). By the 12th month, 40% of those who recovered still have a very high level of IgG antibodies to the S-protein (>500 BAU/ml). In the feces, urine, and blood serum of patients with long-term persistent IgM antibodies, no coronavirus antigens were detected. After vaccination with the Gam-COVID-Vac vaccine, IgG antibodies to the S-protein are detected in 100% of cases and remain at a high level for 4 months, by the 5-6th month, the level of antibodies decreases. During revaccination, the level of IgG antibodies to S-protein reaches high values earlier than during primary vaccination, and remains high for 4 months (observation period). The blood sera of recovered and vaccinated patients have a high virus-neutralizing activity (at least 1:80), while its level is somewhat higher in recovered patients. [ABSTRACT FROM AUTHOR]

In this study involving a cohort of employees of the National Airline company in Lebanon, we assessed humoral immunity levels and the effectiveness of two COVID-19 vaccines, Gam-COVID-Vac versus BNT162b2, after two doses and after a homologous and heterologous BNT162b2 booster, in addition to the impact of hybrid immunity. Vaccine effectiveness (VE) was retrospectively determined against laboratory-confirmed SARS-CoV-2 infection during the periods of Delta and Omicron variants' predominance, separately, and was calculated based on a case–control study design. The humoral immune response, measured by a SARS-CoV-2 anti-spike receptor-binding domain (RBD) IgG titer, was prospectively assessed after the aforementioned vaccination schemes at different time points. This study showed higher effectiveness of BNT162b2 after two doses (81%) compared to two doses of Gam-COVID-Vac (41.8%) against the Delta variant of SARS-CoV-2, which correlated with anti-spike antibody levels. Regarding the Omicron variant, protection against infection and antibody levels were severely compromised and the correlation between an anti-spike IgG titer and effectiveness was lost, unlike the situation during the Delta wave. Considering the booster vaccination schemes, a homologous BNT162b2 booster after a BNT162b2 primary vaccination induced a higher humoral immune response when compared to that induced by a heterologous BNT162b2 booster after a Gam-COVID-Vac primary vaccination. However, the VE of both booster regimens against the Omicron variant was almost equal (64% in the homologous regimen and 57% in heterologous regimen). Hybrid immunity evidenced a better humoral response and a greater and longer protection against Delta and Omicron infections compared to vaccination-induced immunity in COVID-19-naïve individuals. Finally, the findings show that VE waned with time during the same wave, highlighting the importance of reinforcing primary and booster COVID-19 vaccination mainly at the beginning of each wave during the surge of a new variant of concern. [ABSTRACT FROM AUTHOR]

Aim. To analyze the incidence of thrombotic events in unvaccinated and GamCOVID-Vac-vaccinated patients with coronavirus disease 2019 (COVID-19).Material and methods. This prospective study included 316 patients (group 1) vaccinated with two doses of Sputnik V (Gam-COVID-Vac) hospitalized between November 20, 2020 and June 1, 2021 for COVID-19. Group 2 included 754 unvaccinated patients with a positive polymerase chain reaction test for SARSCoV-2.Results. During inhospital period, deaths were recorded only in unvaccinated patients (group 1 — 0%; group 2 — 10,7% (n=87); p

Millions of people have been vaccinated with Gam-COVID-Vac but fine specificities of induced antibodies have not been fully studied. Plasma from 12 naïve and 10 coronavirus disease 2019 (COVID-19) convalescent subjects was obtained before and after two immunizations with Gam-COVID-Vac. Antibody reactivity in the plasma samples (n = 44) was studied on a panel of micro-arrayed recombinant folded and unfolded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins and 46 peptides spanning the spike protein (S) and by immunoglobulin G (IgG) subclass enzyme-linked immunosorbent assay (ELISA). The ability of Gam-COVID-Vac-induced antibodies to inhibit binding of the receptor-binding domain (RBD) to its receptor angiotensin converting enzyme 2 (ACE2) was investigated in a molecular interaction assay (MIA). The virus-neutralizing capacity of antibodies was studied by the pseudo-typed virus neutralization test (pVNT) for Wuhan-Hu-1 and Omicron. We found that Gam-COVID-Vac vaccination induced significant increases of IgG1 but not of other IgG subclasses against folded S, spike protein subunit 1 (S1), spike protein subunit 2 (S2), and RBD in a comparable manner in naïve and convalescent subjects. Virus neutralization was highly correlated with vaccination-induced antibodies specific for folded RBD and a novel peptide (i.e., peptide 12). Peptide 12 was located close to RBD in the N-terminal part of S1 and may potentially be involved in the transition of the pre- to post-fusion conformation of the spike protein. In summary, Gam-COVID-Vac vaccination induced S-specific IgG1 antibodies in naive and convalescent subjects in a comparable manner. Besides the antibodies specific for RBD, the antibodies induced against a peptide close to the N-terminus of RBD were also associated with virus-neutralization.

The course of the COVID-19 pandemic has been critically altered by the availability of vaccines. To assess the risk of COVID-19 in the vaccinated, as compared to the unvaccinated population, as well as the comparative effectiveness of the BBIBP-CorV (Sinopharm), BNT162b2 (Pfizer/BioNTech), Gam-COVID-Vac (Sputnik V) and ChAdOx1 (AstraZeneca) vaccines in the prevention of clinical infection, we carried out a retrospective study of the incidence of clinical COVID-19 in the Belgrade city municipality of Voždovac among both vaccinated and unvaccinated individuals during a 4-month period between 1 July and 31 October 2021. The study included all individuals with a symptomatic infection confirmed by a positive PCR and/or antigen test. Only those who received two vaccine doses were considered as vaccinated. The results showed that of the Voždovac population of 169,567, a total of 81,447 (48%) individuals were vaccinated by the end of the study. Vaccination coverage increased with age, ranging from 1.06% in those below age 18, to even 78.8% in those above 65 years of age. More than one half (57.5%) of all those vaccinated received BBIBP-CorV, while 25.2% received BNT162b2, 11.7% Gam-COVID-Vac and 5.6% ChAdOx1. The overall risk of infection of the vaccinated vs. the unvaccinated was 0.53 (95% CI 0.45–0.61). Compared to the incidence of COVID-19 of 8.05 per 1000 in the unvaccinated population, the relative risk in the vaccinated was 0.35 (95% CI 0.3–0.41). The overall VE was 65%, differing widely among age groups and by vaccine. VE was 79% for BNT162b2, 62% for BBIBP-CorV, 60% for ChAdOx1 and 54% for Gam-COVID-Vac. The VE for BBIBP-CorV and BNT162b2 increased with age. The obtained results demonstrate a significant overall effectiveness of anti-COVID-19 vaccination, which, however, varied significantly among the analyzed vaccines, and was the highest for BNT162b2.

SARS‐CoV‐2 vaccines provide a safe solution with a major impact on reducing the spread of the virus and mild side effects. Research has shown rare cases of myocarditis after mRNA vaccines. This study presents a 29‐year‐old male with chest pain after 48 h of receiving rAd26 and rAd5 vector‐based COVID‐19 vaccine (Sputnik V vaccine). The electrocardiogram revealed ST‐segment elevation. Also, the laboratory screening was remarkable for elevated cardiac Troponin‐I level, and leukocytosis; and echocardiography depicted severe left ventricular systolic dysfunction. Overall, endomyocardial biopsy proved lymphocytic myocarditis such that the patient was successfully treated with immunosuppressive and guideline‐directed medical treatment. [ABSTRACT FROM AUTHOR]

The Republic of San Marino COVID-19 vaccination campaign used Gam-COVID-Vac and Pfizer-BioNTech vaccines. To assess adverse events following immunization (AEFIs), approximately 6000 vaccine recipients were monitored by the ROCCA study, including subgroups with Parkinson's Disease (PD) and Multiple Sclerosis (MS). The purpose of this study is to evaluate short-term AEFIs through a 1-month follow-up. We conducted a longitudinal study, using active surveillance to evaluate the safety profiles of COVID-19 vaccines in PD and MS patients. Participants were actively administered a standardized online questionnaire to collect information on AEFIs. Among all PD and MS assisted by the San Marino hospital, a total of 82 patients completed the questionnaires. One week after administration of the first dose, vaccine recipients reported AEFIs in 26% of cases in the PD group, 67% in the MS group, and 68% in the control group. Participants reported slightly higher rates of AEFIs after dose 2 compared with dose 1, being 29%, 75%, and 78% for PD, MS, control group, respectively. Most of the reported symptoms were mild. Patients with PD and MS reported few AEFIs after administration of the COVID-19 vaccines. The frequency of AEFIs in the PD population was significantly lower than in the control group. [ABSTRACT FROM AUTHOR]

Summary: Background: Gam-COVID-Vac (SPUTNIK V) has been granted emergency use authorization in 70 nations and has been administered to millions worldwide. However, there are very few peer-reviewed studies describing its effects. Independent reports regarding safety and effectiveness could accelerate the final approval by the WHO. We aimed to study the long-term humoral immune response in naïve and previously infected volunteers who received SPUTNIK V. Methods: Humoral immune responses, assayed by anti-SARS-CoV-2-spike-RBD IgG ELISA and neutralization assays, were measured in 602 healthcare workers at 0, 14, 28, 60 and 180 days after receiving SPUTNIK V between December 2020 and July 2021 in Tucumán, Argentina. Findings: Seroconversion was detected in 97% of individuals after 28 days post-vaccination (dpv) (N = 405). Anti-RBD titers began to decrease after 60 dpv (N = 328), but remained detectable in 94% at 90 dpv (N = 224). At 180 dpv, anti-RDB titers persisted in 31% (N = 146). Previous infection triggered an increased immune response to the first dose and increased neutralization activity against variants of concern (VOC). Second doses in previously infected individuals further increased titers, even 90 dpv (N = 75). Basal antibody titers had more influence on post-vaccination anti-RBD responses than the time elapsed between diagnosis and vaccination (N = 274). Interpretation: Data presented herein provides essential knowledge regarding the kinetics of antibodies induced by SPUTNIK V up to six months after immunization, and suggests that when considering one-dose vaccination policies for individuals with previous SARS-CoV-2 infection, serological studies to determine basal titers may be important, independent of when diagnosis occurred. Funding: Tucumán Public Health System (SIPROSA), Argentinean National Research Council (CONICET), National University of Tucumán (UNT).

The mortality rate estimated by the WHO worldwide for CO- VID-19 has been 5.7%, much higher than other communicable infectious diseases, so it is essential to apply a vaccine to the population to reduce the viral spread, according to the WHO there are 23 projects in clinical phase stage III, such as vaccines: ChadOx1, nCov-19, Gam-COVID-Vac, CoronaVac that show promising results in research published by The Lancet Infection Diseases journal, for which we consider correlating the three vaccines and determining which is safer, generates greater immunogenicity and less reactogenicity in volunteer participants, for which we conducted a review bibliography and a meta-analysis of high impact scientific articles, concluding that the three vaccines generate a rapid and intense immune response against SARS-CoV-2, neutralizing antibodies had elevated titers in participants at 28 days, who increased and remained stable with a second dose, although each of them have been tested in different numbers and populations, applying recombinant adenoviral vectors and chemically inactivated virions with adjuvant and placebo for which they are totally different but with the same purpose to generate memory antibodies against SARS-CoV-2. [ABSTRACT FROM AUTHOR]

In the context of the ongoing coronavirus disease 2019 (COVID-19) pandemic, it is extremely important to study immunogenicity and immune response duration in different vaccines.Aim. As part of a prospective observational study, to study the levels of anti-SARS-CoV-2 S-protein IgG antibodies in individuals vaccinated with the Gam-COVID-Vac and CoviVac vaccines.Material and methods. The data of 93 people who completed the first 3 visits were analyzed, 23 of whom were vaccinated with the Gam-COVID-Vac vaccine and 70 people — with the CoviVac vaccine. We collected blood before the injection of vaccine doses I and II, as well as 42 days after the injection of dose I in order to quantitatively determine IgG levels. The level of anti-SARS-CoV-2 S-protein IgG antibodies was determined using the SARS-CoV-2 IgG ELISA-BEST reagent kit on the InfiniteF50 TECAN system.Results. A significant increase in anti-SARS-CoV-2 S-protein IgG antibodies was observed in those vaccinated with Gam-COVID-Vac. In the group of CoviVac vaccine, an increase in the level anti-SARS-CoV-2 S-protein IgG antibodies in absolute values was recorded, however, this increase did not reach statistical significance.Conclusion. The data obtained show that the level of anti-SARS-CoV-2 S-protein antibodies 42 days after Gam-COVID-Vac vaccination is significantly higher than after CoviVac vaccination. However, an increase in the level of IgG in both groups indicates the ability of both vaccines to stimulate the production of anti-SARS-CoV antibodies.

The COVID-19 pandemic has required extensive research on the new coronavirus SARS-CoV-2 and the creation of new highly effective vaccines. The presence of T-cells in the body that respond to virus antigens suggests adequate antiviral immunity. We investigated T-cell immunity in individuals who recovered from mild and moderate COVID-19 and in individuals vaccinated with the Gam-COVID-Vac combined vector vaccine. The ELISPOT method was used to determine the number of T-cells responding with IFN-γ synthesis to stimulation by peptides containing epitopes of the S-protein or N-, M-, ORF3, and ORF7 proteins, using peripheral blood mononuclear cells (PBMCs). At the same time, the multiplex method was used to determine the accumulation of IFN-γ and other cytokines in the culture medium. According to the data obtained, the proportion of positive conclusions about the T-cell immune response to SARS-CoV-2 antigens in control, recovered, and vaccinated individuals was 12%, 70%, and 52%, respectively. At the same time, more than half of the vaccinated individuals with a T-cell response were sensitized to the antigens of N-, M-, ORF3, and ORF7 proteins not produced by Gam-COVID-Vac, indicating a high likelihood of asymptomatic SARS-CoV-2 infection. Increased IFN-γ release by single sensitized T-cells in response to specific stimulation in recovered and vaccinated individuals did not result in the accumulation of this and other cytokines in the culture medium. These findings suggest a balance between cytokine production and utilization by immunocompetent cells as a prerequisite for providing a controlled cytokine signal and avoiding a “cytokine storm”.

Many available SARS-CoV-2 vaccines demonstrated good humoral response, but studies directly comparing their immunogenicity in the general population are lacking. We evaluated the medium–term kinetics of anti-S SARS-CoV-2 antibodies (Abs) at one and six months after the second dose of BNT162b2, BBIBP-CorV, and Gam-COVID-Vac. Immunogenicity at six months was directly compared between BNT162b2, BBIBP-CorV, Gam-COVID-Vac, and ChAdOx1 nCoV-19. Participants ≥ 20 years old from Novi Sad, Serbia, without prior SARS-CoV-2 infection, were included. Anti S1/S2 IgG antibodies were measured using quantitative LIAISON SARS-CoV-2 assay. A total of 368 participants were included: 231 (62.77%) had sera collected at two time points. Two doses of BNT162b2 were received by 37.50% of participants, followed by BBIBP-CorV (22.01%), Gam-COVID-Vac (21.47%), and ChAdOx1 nCoV-19 (19.02%). Mean Ab levels at the 28th day and 6 months were 216.55 (SD = 105.73) AU/mL and 75.68 (SD = 57.30) for BNT162b2, 194.38 (SD = 140.24) and 90.53 (SD = 111.30) for Gam-COVID-Vac, and 72.74 (SD = 80.04) and 24.43 (SD = 38.43) for BBIBP-CorV group (p < 0.01, between two time points across all three groups), with a significant difference between women and men (p < 0.01, for both sexes). At the sixth month post-vaccination, the highest mean Ab level was detected in Gam-COVID-Vac group (91.28 AU/mL, SD = 95.96), followed by BNT162b2 (85.25 AU/mL, SD = 60.02), ChAdOx1 nCoV-19 (64.22 AU/mL, SD = 65.30), and BBIBP-CorV (25.26 AU/mL, SD = 36.92) (p < 0.01). Anti-spike IgG persistence was demonstrated six months post-vaccination with a significant decline in Ab levels. These results suggest a lower protection against SARS-CoV-2 over time. Our findings support the introduction of additional (booster) doses.

Vaccination against COVID-19 has occurred in Russia for more than two years. According to the Russian official clinical guidelines to maintain tense immunity in the conditions of the ongoing COVID-19 pandemic, it is necessary to use booster immunization six months after primary vaccination or a previous COVID-19 contraction. It is especially important to ensure the maintenance of protective immunity in the elderly, who are at risk of severe courses of COVID-19. Meanwhile, the immunological effectiveness of the booster doses has not been sufficiently substantiated. To investigate the immunogenicity of Sputnik V within the recommended revaccination regimen and evaluate the effectiveness of booster doses, we conducted this study on 3983 samples obtained from individuals previously vaccinated with Sputnik V in Moscow. We analyzed the level of antibodies in BAU/mL three times: (i) six months after primary immunization immediately before the booster (RV), (ii) 3 weeks after the introduction of the first component of the booster (RV1), and (iii) 3 weeks after the introduction of the second component of the booster (RV2). Six months after the primary vaccination with Sputnik V, 95.5% of patients maintained a positive level of IgG antibodies to the receptor-binding domain (RBD) of SARS-CoV-2. The degree of increase in the specific virus-neutralizing antibodies level after revaccination increased with a decrease in their initial level just before the booster dose application. In the group of people with the level of antibodies up to 100 BAU/mL six months after the vaccination, a more than eightfold increase (p < 0.001, Wilcoxon criterion with Bonferroni adjustment) in the level of specific antibodies was observed (Me = 8.84 (IQR: 3.63–30.61)). A significant increase in the IgG level after receiving both the first and the second booster doses occurred at the initial titer level up to 300 BAU/ mL (p < 0.001) in those who did not contract COVID-19 in the past and up to 100 BAU/mL (p < 0.001) in those who were previously infected with SARS-CoV-2. A significant increase in the antibody level after the first dose of the booster was noted for people who had up to 500 BAU/mL (p < 0.05), regardless of the previous COVID-19 infection. Thus, revaccination is most effective in individuals with an antibody level below 500 BAU/mL, regardless of the vaccinee age and COVID-19 contraction. For the first time, it has been shown that a single booster dose of the Sputnik vaccine is sufficient to form a protective immunity in most vaccinees regardless of age and preexisting antibody level.

Background: In August 2020, Sputnik V was registered as Gam-COVID-Vac by the Russian Ministry of Health, and since December 2020 it has been distributed in 61 countries worldwide. On 25 February 2021, the Republic of San Marino started its vaccination campaign, which includes Sputnik V. Our aim was to describe the adverse events following immunization (AEFIs) with this vaccine through participant-based active surveillance in the country. Methods: Beginning from 4 March to 8 April 2021, a nationwide study was conducted on San Marino's population aged 18–89 years who received one or two doses of Sputnik V. E-questionnaire dissemination occurred through e-mails, QR-codes or live/phone interviews ~7 days after the first and second vaccine dose. A descriptive analysis was conducted to quantify AEFI incidence on both occasions, stratifying results by type and severity of symptoms. Findings: Mean age of the 2558 vaccine recipients was 66±14 years. First-dose AEFI incidence was 53.3% (systemic reactions at 42.2%), while second-dose AEFI incidence was 66.8% (systemic reactions at 50.4%) (n = 1288). In general, 76.0% of two-dose recipients reported some AEFIs after either vaccine dose, and 2.1% suffered severe reactions; in 60- to 89-year-olds (n = 1021), AEFI incidence was 70.0%, with 53.0% of subjects describing systemic reactions and 0.8% reporting severe symptoms. The most frequent symptoms were local pain, asthenia, headache and joint pain. Interpretation: Our results, albeit preliminary, suggest that Sputnik V has a high tolerability profile in the population aged ≥60 years in terms of short-term AEFIs. Funding: None.

In this study involving a cohort of employees of the National Airline company in Lebanon, we assessed humoral immunity levels and the effectiveness of two COVID-19 vaccines, Gam-COVID-Vac versus BNT162b2, after two doses and after a homologous and heterologous BNT162b2 booster, in addition to the impact of hybrid immunity. Vaccine effectiveness (VE) was retrospectively determined against laboratory-confirmed SARS-CoV-2 infection during the periods of Delta and Omicron variants’ predominance, separately, and was calculated based on a case–control study design. The humoral immune response, measured by a SARS-CoV-2 anti-spike receptor-binding domain (RBD) IgG titer, was prospectively assessed after the aforementioned vaccination schemes at different time points. This study showed higher effectiveness of BNT162b2 after two doses (81%) compared to two doses of Gam-COVID-Vac (41.8%) against the Delta variant of SARS-CoV-2, which correlated with anti-spike antibody levels. Regarding the Omicron variant, protection against infection and antibody levels were severely compromised and the correlation between an anti-spike IgG titer and effectiveness was lost, unlike the situation during the Delta wave. Considering the booster vaccination schemes, a homologous BNT162b2 booster after a BNT162b2 primary vaccination induced a higher humoral immune response when compared to that induced by a heterologous BNT162b2 booster after a Gam-COVID-Vac primary vaccination. However, the VE of both booster regimens against the Omicron variant was almost equal (64% in the homologous regimen and 57% in heterologous regimen). Hybrid immunity evidenced a better humoral response and a greater and longer protection against Delta and Omicron infections compared to vaccination-induced immunity in COVID-19-naïve individuals. Finally, the findings show that VE waned with time during the same wave, highlighting the importance of reinforcing primary and booster COVID-19 vaccination mainly at the beginning of each wave during the surge of a new variant of concern.

The Republic of San Marino COVID-19 vaccination campaign used Gam-COVID-Vac and Pfizer-BioNTech vaccines. To assess adverse events following immunization (AEFIs), approximately 6000 vaccine recipients were monitored by the ROCCA study, including subgroups with Parkinson’s Disease (PD) and Multiple Sclerosis (MS). The purpose of this study is to evaluate short-term AEFIs through a 1-month follow-up. We conducted a longitudinal study, using active surveillance to evaluate the safety profiles of COVID-19 vaccines in PD and MS patients. Participants were actively administered a standardized online questionnaire to collect information on AEFIs. Among all PD and MS assisted by the San Marino hospital, a total of 82 patients completed the questionnaires. One week after administration of the first dose, vaccine recipients reported AEFIs in 26% of cases in the PD group, 67% in the MS group, and 68% in the control group. Participants reported slightly higher rates of AEFIs after dose 2 compared with dose 1, being 29%, 75%, and 78% for PD, MS, control group, respectively. Most of the reported symptoms were mild. Patients with PD and MS reported few AEFIs after administration of the COVID-19 vaccines. The frequency of AEFIs in the PD population was significantly lower than in the control group.

Real-life data on the performance of vaccines against SARS-CoV-2 are still limited. We here present the rates of detection and levels of antibodies specific for the SARS-CoV-2 spike protein RBD (receptor binding domain) elicited by four vaccines available in Serbia, including BNT-162b2 (BioNTech/Pfizer), BBIBP-CorV (Sinopharm), Gam-COVID-Vac (Gamaleya Research Institute) and ChAdOx1-S (AstraZeneca), compared with those after documented COVID-19, at 6 weeks and 3 months post first vaccine dose or post-infection. Six weeks post first vaccine dose, specific IgG antibodies were detected in 100% of individuals fully vaccinated with BNT-162b2 (n = 100) and Gam-COVID-Vac (n = 12) and in 81.7% of BBIBP-CorV recipients (n = 148), while one dose of ChAdOx1-S (n = 24) induced specific antibodies in 75%. Antibody levels elicited by BNT-162b2 were higher, while those elicited by BBIBP-CorV were lower, than after SARS-CoV-2 infection. By 3 months post-vaccination, antibody levels decreased but remained ≥20-fold above the cut-off in BNT-162b2 but not in BBIBP-CorV recipients, when an additional 30% were seronegative. For all vaccines, antibody levels were higher in individuals with past COVID-19 than in naïve individuals. A total of twelve new infections occurred within the first 3 months post-vaccination, eight after the first dose of BNT-162b2 and ChAdOx1-S (one each) and BBIBP-CorV (six), and four after full vaccination with BBIBP-CorV, but none required hospitalization.

Background: COVID-19 vaccine booster doses restore vaccine effectiveness lost from waning immunity and emerging variants. Fractional dosing may improve COVID-19 booster acceptability and uptake and will reduce the per-dose cost of COVID-19 booster programmes. We sought to quantify the immunogenicity, reactogenicity, and safety of a half-dose BNT162b2 (Pfizer-BioNTech) booster relative to the standard formulation., Methods: This randomised, controlled, non-inferiority trial recruited adults in Mongolia primed with a two-dose homologous ChAdOx1 nCov-19 (Oxford-AstraZeneca, n = 129 participants), BBIBP-CorV (Sinopharm (Beijing), n = 399), or Gam-COVID-Vac (Gamaleya, n = 70) schedule. Participants were randomised (1:1) to receive a 15 μg (half-dose) or 30 μg (full-dose) BNT162b2 booster. Participants and study staff assessing reactogenicity were blinded up to day 28. Co-primary endpoints were Wuhan-Hu-1 anti-spike S1 IgG seroresponse 28 days post-boosting and reactogenicity within 7 days of boosting. The non-inferiority margin for the absolute difference in seroresponse was -10%. Differences in seroresponse were estimated from logistic regression with marginal standardisation. Geometric mean ratios of IgG were also estimated. ClinicalTrials.gov Identifier: NCT05265065., Findings: Between May 27th and September 30th, 2022, 601 participants were randomized to full-dose BNT162b2 (n = 300) or half-dose (n = 301). 598 were included in safety analyses, and 587 in immunological analyses. The frequency of grade 3-4 reactions was similar between arms (half-dose: 4/299 [1.3%]; full-dose: 6/299 [2.0%]). Across all severity grades, half-dose recipients reported fewer local and systemic reactions (60% versus 72% and 25% versus 32%, respectively). Seroresponse was 84.7% (250/295) and 86.6% (253/292) in the half-dose and full-dose arms, respectively (Difference: -2.8%; 95% CI -7.7, 2.1). Geometric mean IgG titres were similar in those receiving full and half-dose boosters for the ChAdOx1 and BBIBP-CorV primed groups, but lower in the half-dose arm in Gam-COVID-Vac-primed participants (GMR: 0.71; 95% CI 0.54, 0.93)., Interpretation: Half-dose BNT162b2 boosting elicited an immune response that was non-inferior to a full-dose, with fewer reactions, in adults primed with ChAdOx1 nCov-19 or BBIBP-CorV. Half-dose boosting may not be suitable in adults primed with Gam-COVID-Vac. Half-dose BNT162b2 boosting may be considered in populations primed with ChAdOx1 nCov-19 or BBIBP-CorV., Funding: Coalition for Epidemic Preparedness Innovations (CEPI)., Competing Interests: The National Centre for Communicable Diseases (NCCD) is part of the Mongolian Ministry of Health and is a focal point for WHO International Health Regulations. CDN receives funding from Merck Sharp & Dohme as a co-investigator/biostatistician on a Merck Investigator Studies Program grant on pneumococcal serotype epidemiology in children with empyema, and from Pfizer as a co-investigator/biostatistician on a clinical research collaboration on PCV vaccination in Mongolia. PVL receives funding from the Gates Foundation and the National Health and Medical Research Council (NHMRC, Australia). CvM is the principal investigator on a Pfizer clinical research collaborative grant on PCV vaccination in Mongolia. CvM has received honoraria from Pfizer and Merck for participation in expert panels. KMu was on the Data Safety Monitoring Board of a Novavax Covid-19 vaccine trial, which is now complete, and was funded to attend the October 2022 and March 2023 Strategic Advisory Group of Experts on Immunization (SAGE) meetings as a SAGE member. Other authors declare no competing interests., (© 2023 The Authors.)