Browsing by Author "Vuković, Vladimir (56545340100)"

Real-world evidence of the vaccine effectiveness (VE) of different COVID-19 vaccines is needed in order to better shape vaccine recommendations and policies and increase vaccine acceptance, especially among vulnerable populations such as the elderly. We analyzed the early effectiveness of four COVID-19 vaccines, namely BNT162b2, BBIBP-CorV, Gam-COVID-Vac and ChAdOx1 nCoV-19 in population aged ≥60 years for symptomatic, mild and severe COVID-19, in the period January–April 2021 in Vojvodina, a northern province of Serbia. Incidence rates of SARS-CoV-2 infection were calculated using data from the provincial COVID-19 surveillance registry, and vaccination coverage data were obtained from the nationwide registry of administered COVID-19 vaccines. During the observation period, 134,535 subjects aged ≥60 years were fully vaccinated, of whom 87.7% received BBIBP-CorV, 7.1% BNT162b2 and 5.2% Gam-COVID-Vac vaccines. The estimated VE in fully vaccinated persons was 86.9% (95% CI, 86–87.7) for BBIBP-CorV, 95% (95% CI, 92.4–96.7) for Gam-COVID-Vac and 99% (95% CI, 97.8–99.5) for BNT162b2, while VE after the first dose of ChAdOx1 nCoV-19 was 88.6% (95% CI, 80.5–93.4). Estimates were similar when stratifying the analyses to severe and mild SARS-CoV-2 infections. Our analysis provides evidence of high early effectiveness of BNT162b2, BBIBP-CorV, Gam-COVID-Vac and ChAdOx1 nCoV-19 in elderly people in preventing symptomatic, severe and mild COVID-19 disease, particularly after being fully vaccinated. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Real-world evidence of the vaccine effectiveness (VE) of different COVID-19 vaccines is needed in order to better shape vaccine recommendations and policies and increase vaccine acceptance, especially among vulnerable populations such as the elderly. We analyzed the early effectiveness of four COVID-19 vaccines, namely BNT162b2, BBIBP-CorV, Gam-COVID-Vac and ChAdOx1 nCoV-19 in population aged ≥60 years for symptomatic, mild and severe COVID-19, in the period January–April 2021 in Vojvodina, a northern province of Serbia. Incidence rates of SARS-CoV-2 infection were calculated using data from the provincial COVID-19 surveillance registry, and vaccination coverage data were obtained from the nationwide registry of administered COVID-19 vaccines. During the observation period, 134,535 subjects aged ≥60 years were fully vaccinated, of whom 87.7% received BBIBP-CorV, 7.1% BNT162b2 and 5.2% Gam-COVID-Vac vaccines. The estimated VE in fully vaccinated persons was 86.9% (95% CI, 86–87.7) for BBIBP-CorV, 95% (95% CI, 92.4–96.7) for Gam-COVID-Vac and 99% (95% CI, 97.8–99.5) for BNT162b2, while VE after the first dose of ChAdOx1 nCoV-19 was 88.6% (95% CI, 80.5–93.4). Estimates were similar when stratifying the analyses to severe and mild SARS-CoV-2 infections. Our analysis provides evidence of high early effectiveness of BNT162b2, BBIBP-CorV, Gam-COVID-Vac and ChAdOx1 nCoV-19 in elderly people in preventing symptomatic, severe and mild COVID-19 disease, particularly after being fully vaccinated. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

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. © 2022 by the authors.

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. © 2022 by the authors.

Objectives: To assess whether pneumococcal nasopharyngeal carriage among children aged 24–60 months reduced during the coronavirus disease 2019 (COVID-19) pandemic in Novi Sad, Serbia, and to investigate the overall prevalence of carriage, serotype distribution and dominant serotypes 2–3 years after the introduction of pneumococcal conjugate vaccine 10. Design and methods: This prospective, observational study was conducted in February–March 2020, September–November 2020 and April–June 2021, enabling the comparison of results in the pre-pandemic/early pandemic period with two periods during the COVID-19 pandemic. Pneumococci were identified by standard microbiological methods. Serotype identification was performed using conventional multiplex polymerase chain reaction assays. Results: Among 1623 children tested, 515 (31.7%, 95% confidence interval 29.4–34.0%) carried pneumococci. A significant increase in prevalence was found between February–March 2020 and September–November 2020 (P=0.0085), with no difference found between September–November 2020 and April–June 2021 (P=0.0524). Pneumococcal colonization was significantly higher in children who were fully vaccinated and among children who attended day care centres. The dominant serotypes were 15B, 6B, 19F, 11A, 6C, 6A, 3, 23F and 19A, representing 66.4% of all isolates. Conclusions: This study found that pneumococcal nasopharyngeal carriage in children aged 24–60 months was high before the COVID-19 pandemic, and then increased during the pandemic. This rules out a major role of COVID-19 in the suppression of carriage and, probably, transmission. © 2022 The Author(s)

Healthcare workers (HCWs) are a vulnerable and critical population in the ongoing response to the SARS-CoV-2 pandemic. We aimed to estimate the seroprevalence in HCWs considering all of their previous contacts with the SARS-CoV-2 virus and/or the immunity acquired through their immunization against COVID-19 before the advent of the Omicron variants BA.4/BA.5. Serum samples were collected from 28 March to 10 June 2022. We covered 25% out of all the people who worked in some of the government healthcare centers (primary, secondary, and tertiary level) across the entire Autonomous Province of Vojvodina (Northern Serbia). Two serological tests (Anti-SARS-CoV-2 QuantiVac ELISA and LIAISON® SARS-CoV-2 TrimericS) were used to detect anti-spike IgG antibodies. The overall prevalence of the SARS-CoV-2 antibody among the 6936 HCWs was 92.96% [95% CI 92.33–93.55]. Regarding the type of serological test, there was a statistically significant (p = 0.0079) difference of the seropositivity obtained by the LIAISON® SARS-CoV-2 TrimericS (93.87%, 95% CI 92.97–94.69) and Anti-SARS-CoV-2 QuantiVac ELISA (92.23%, 95% CI 91.34–93.06) tests. Seropositivity to SARS-CoV-2 significantly (p < 0.0001) increased with the number of SARS-CoV-2 infections combined with the number of doses of the SARS-CoV-2 vaccines received. A vast majority of the HCWs in Vojvodina had detectable levels of antibodies to the spike protein of SARS-CoV-2, but despite this high seropositivity, it is unknown whether this herd immunity among HCWs is protective against the new variants of concern. Further research should evaluate the rates of reinfections and the associated severity of COVID-19 caused by the Omicron sublineages and/or new variants of SARS-CoV-2 among HCWs. © 2022 by the authors.

Healthcare workers (HCWs) are a vulnerable and critical population in the ongoing response to the SARS-CoV-2 pandemic. We aimed to estimate the seroprevalence in HCWs considering all of their previous contacts with the SARS-CoV-2 virus and/or the immunity acquired through their immunization against COVID-19 before the advent of the Omicron variants BA.4/BA.5. Serum samples were collected from 28 March to 10 June 2022. We covered 25% out of all the people who worked in some of the government healthcare centers (primary, secondary, and tertiary level) across the entire Autonomous Province of Vojvodina (Northern Serbia). Two serological tests (Anti-SARS-CoV-2 QuantiVac ELISA and LIAISON® SARS-CoV-2 TrimericS) were used to detect anti-spike IgG antibodies. The overall prevalence of the SARS-CoV-2 antibody among the 6936 HCWs was 92.96% [95% CI 92.33–93.55]. Regarding the type of serological test, there was a statistically significant (p = 0.0079) difference of the seropositivity obtained by the LIAISON® SARS-CoV-2 TrimericS (93.87%, 95% CI 92.97–94.69) and Anti-SARS-CoV-2 QuantiVac ELISA (92.23%, 95% CI 91.34–93.06) tests. Seropositivity to SARS-CoV-2 significantly (p < 0.0001) increased with the number of SARS-CoV-2 infections combined with the number of doses of the SARS-CoV-2 vaccines received. A vast majority of the HCWs in Vojvodina had detectable levels of antibodies to the spike protein of SARS-CoV-2, but despite this high seropositivity, it is unknown whether this herd immunity among HCWs is protective against the new variants of concern. Further research should evaluate the rates of reinfections and the associated severity of COVID-19 caused by the Omicron sublineages and/or new variants of SARS-CoV-2 among HCWs. © 2022 by the authors.