Effectiveness of Pfizer-BioNTech (BNT162b2) Vaccine Among Adolescents (Aged 12-15 Years): An Observational Study in Qatar.

In May 2021, Qatar launched the BNT162b2 COVID-19 vaccine campaign for adolescents aged 12 to 15 years across all 27 health centers. Our study assessed the safety and efficacy of the vaccine among vaccinated and nonvaccinated adolescents in Qatar. Using a retrospective observational study, we analyzed the medical records of 1956 adolescents who were severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive from June 17 to December 17, 2021. The mean age for the vaccinated group was 13.89 ± 0.93 years, and for the nonvaccinated group, it was 12.99 ± 0.93 years. In the vaccinated group, 46% were male (n = 185) compared with 53% in the nonvaccinated group (n = 827) and 54% were female in the vaccinated group (n = 217) versus 47% in the nonvaccinated group (n = 727). Our findings demonstrate satisfactory protection provided by the Pfizer-BioNTech COVID-19 vaccine, with only one fifth of the study population contracting SARS-CoV-2 infections after the double-dose regimen. These results highlight the importance of maximizing vaccination coverage and considering booster doses for adolescents to enhance protection.

The subdued post-boost spike-directed secondary IgG antibody response in Ugandan recipients of the Pfizer-BioNTech BNT162b2 vaccine has implications for local vaccination policies.

Introduction: This study aimed to delineate longitudinal antibody responses to the Pfizer-BioNTech BNT162b2 COVID-19 vaccine within the Ugandan subset of the Sub-Saharan African (SSA) demographic, filling a significant gap in global datasets. Methods: We enrolled 48 participants and collected 320 specimens over 12 months after the primary vaccination dose. A validated enzyme-linked immunosorbent assay (ELISA) was used to quantify SARS-CoV-2-specific IgG, IgM, and IgA antibody concentrations (ng/ml) and optical densities (ODs). Statistical analyses included box plots, diverging bar graphs, and the Wilcoxon test with Bonferroni correction. Results: We noted a robust S-IgG response within 14 days of the primary vaccine dose, which was consistent with global data. There was no significant surge in S-IgG levels after the booster dose, contrasting trends in other global populations. The S-IgM response was transient and predominantly below established thresholds for this population, which reflects its typical early emergence and rapid decline. S-IgA levels rose after the initial dose then decreased after six months, aligning with the temporal patterns of mucosal immunity. Eleven breakthrough infections were noted, and all were asymptomatic, regardless of the participants' initial S-IgG serostatus, which suggests a protective effect from vaccination. Discussion: The Pfizer-BioNTech BNT162b2 COVID-19 vaccine elicited strong S-IgG responses in the SSA demographic. The antibody dynamics distinctly differed from global data highlighting the significance of region-specific research and the necessity for customised vaccination strategies.