Immunogenicity of BNT162b2, BBIBP-CorV and Gam-COVID-Vac vaccines and immunity after natural SARS-CoV-2 infection-A comparative study from Novi Sad, Serbia

• Published in: PloS one Vol. 17; no. 2; p. e0263468
• Main Authors: Petrovic, Vladimir, Ristic, Mioljub, Patic, Aleksandra, Markovic, Milos, Vukovic, Vladimir
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02-02-2022; Public Library of Science (PLoS)
• Subjects: Adult; Age; Antibodies; Antibodies - analysis; Antibodies - blood; Antibodies, Viral - blood; Asymptomatic; Biology and Life Sciences; BNT162 Vaccine - immunology; Comparative studies; Convalescence; Coronaviruses; COVID-19; COVID-19 - blood; COVID-19 - immunology; COVID-19 - therapy; COVID-19 vaccines; COVID-19 Vaccines - immunology; COVID-19 Vaccines - therapeutic use; Cross-Sectional Studies; Drug dosages; Durability; Female; Health aspects; Humans; Immune response; Immune system; Immunity - immunology; Immunity, Innate - immunology; Immunogenicity; Immunogenicity, Vaccine - immunology; Immunoglobulin G; Immunoglobulin G - analysis; Immunoglobulin G - blood; Immunology; Infections; Laboratories; Male; Medicine; Medicine and Health Sciences; Middle Aged; Pandemics; Pneumonia; Proteins; Public health; SARS-CoV-2 - immunology; Serbia; Seroconversion; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Spike Glycoprotein, Coronavirus - immunology; Statistical analysis; Treatment Outcome; Vaccination; Vaccines; Vaccines, Inactivated - immunology; Vaccines, Synthetic - immunology; Viral diseases; Serbia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0263468

Mass vaccination is the key element in controlling current COVID-19 pandemic. Studies comparing immunogenicity of different COVID-19 vaccines are largely lacking. We aimed at measuring anti-S antibody (Ab) levels in individuals fully vaccinated with BNT162b2, BBIBP-CorV and Gam-COVID-Vac, as well as in COVID-19 convalescents.
In this cross-sectional study, serum was collected from 400 age- and sex-matched participants, 100 fully vaccinated with BNT162b2, 100 with BBIBP-CorV and 100 with Gam-COVID-Vac on the 28th day after the second vaccine dose, and 100 recovered from COVID-19 at least 28 days after symptom(s) resolution. Sera were analyzed using the LIAISON SARS-CoV-2 S1/S2 IgG assay (DiaSorin, Saluggia, Italy). Wilcoxon rank-sum or Kruskal-Wallis tests was used for comparison of Ab levels.
Highest mean value (210.11, SD = 100.42) was measured in the BNT162b2 group, followed by Gam-COVID-Vac (171.11, SD = 120.69) and BBIBP-CorV (68.50, SD = 72.78) AU/mL (p<0.001). Significant differences in antibody levels were found between BNT162b2 and BBIBP-CorV (p<0.001), BNT162b2 and Gam-COVID-Vac (p = 0.001), as well as BBIBP-CorV and Gam-COVID-Vac groups (p<0.001). Percentage of seropositive was 81% in the convalescent group, 83% in BBIBP-CorV vaccinated and 100% in BNT162b2 and Gam-COVID-Vac. When comparing measured antibody levels in vaccinated to those in COVID-19 recovered, significantly higher antibody levels were found for vaccinated with BNT162b2 (p<0.001), and with Gam-COVID-Vac (p<0.001), while for BBIBP-CorV there was no statistically significant difference (p = 0.641).
All three investigated vaccines, BNT162b2, BBIBP-CorV and Gam-COVID-Vac, provide robust immune response 28 days after the second dose of vaccine, in the majority of participants. All individuals vaccinated with BNT162b2 and Gam-COVID-Vac seroconverted, while in vaccinated with BBIBP-CorV and COVID-19 recovered seroconversion rates were lower. Although less potent compared to other two vaccines, immune response after BBIBP-CorV was similar to response measured in convalescents. Challenge still remains to examine dynamics and durability of immunoprotection.