Vaccines (Dec 2022)

Population-Based Analysis of the Immunoglobulin G Response to Different COVID-19 Vaccines in Brazil

  • Nigella M. Paula,
  • Marcelo S. Conzentino,
  • Ana C. A. Gonçalves,
  • Renata da Silva,
  • Karin V. Weissheimer,
  • Carlos H. S. Kluge,
  • Paulo H. S. A. Marins,
  • Haxley S. C. Camargo,
  • Lucas R. P. Farias,
  • Thamyres P. Sant’Ana,
  • Letícia R. Vargas,
  • Juliane D. Aldrighi,
  • Ênio S. Lima,
  • Guiomar T. Jacotenski,
  • Fabio O. Pedrosa,
  • Alan G. Gonçalves,
  • Emerson Joucoski,
  • Luciano F. Huergo

DOI
https://doi.org/10.3390/vaccines11010021
Journal volume & issue
Vol. 11, no. 1
p. 21

Abstract

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(1) Background: COVID-19 vaccination in Brazil has been performed mostly with CoronaVac (Sinovac), ChAdOx1-S (AstraZeneca-University of Oxford) and BNT162b2 (Pfizer-BioNTech) vaccines. The titers of IgG antibodies reactive to the SARS-CoV-2 spike protein correlate with vaccine efficacy. Studies comparing vaccine immunogenicity in a real-world scenario are lacking. (2) Methods: We performed a population-based study to analyze the immunoglobulin G response to different COVID-19 vaccines. Citizens older than 18 years (n = 2376) provided personal data, a self-declaration of any previous COVID-19 positive tests and information regarding COVID-19 vaccination: the vaccine popular name and the date of each dose. Blood samples were collected and the levels of IgG reactive to SARS-CoV-2 antigens were determined and compared between different vaccine groups. (3) Results: The seroconversion for anti-spike IgG achieved > 95% by February 2022 and maintained stable until June 2022. Higher anti-spike IgG titers were detected in individuals vaccinated with BNT162b2, followed by ChAdOx1-S and CoronaVac. The anti-spike IgG response was negatively correlated with age and interval after the second dose for the BNT162b2 vaccine. Natural infections boosted anti-spike IgG in those individuals who completed primary vaccination with ChAdOx1-S and CoronaVac, but not with BNT162b2. The levels of anti-spike IgG increased with the number of vaccine doses administered. The application of BNT162b2 as a 3rd booster dose resulted in high anti-spike IgG antibody titers, despite the type of vaccine used during primary vaccination. (4) Conclusions: Our data confirmed the effectiveness of the Brazilian vaccination program. Of the vaccines used in Brazil, BNT162b2 performed better to elicit anti-spike protein IgG after primary vaccination and as a booster dose and thus should be recommended as a booster whenever available. A continuous COVID-19 vaccination program will be required to sustain anti-spike IgG antibodies in the population.

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