Immunogenicity and reactogenicity of a third dose of BNT162b2 vaccine for COVID-19 after a primary regimen with BBIBP-CorV or BNT162b2 vaccines in Lima, Peru

Natalia Vargas-Herrera, Manuel Fernández-Navarro, Nestor E. Cabezudo, Percy Soto-Becerra, Gilmer Solís-Sánchez, Stefan Escobar-Agreda, Javier Silva-Valencia, Luis Pampa-Espinoza, Ricardo Bado-Pérez, Lely Solari, Roger V. Araujo-Castillo

Research output: Contribution to journalArticlepeer-review


BACKGROUND: The administration of a third (booster) dose of COVID-19 vaccines in Peru initially employed the BNT162b2 (Pfizer) mRNA vaccine. The national vaccination program started with healthcare workers (HCW) who received BBIBP-CorV (Sinopharm) vaccine as primary regimen and elderly people previously immunized with BNT162b2. This study evaluated the reactogenicity and immunogenicity of the "booster" dose in these two groups in Lima, Peru. METHODS: We conducted a prospective cohort study, recruiting participants from November to December of 2021 in Lima, Peru. We evaluated immunogenicity and reactogenicity in HCW and elderly patients previously vaccinated with either two doses of BBIBP-CorV (heterologous regimen) or BTN162b2 (homologous regimen). Immunogenicity was measured by anti-SARS-CoV-2 IgG antibody levels immediately before boosting dose and 14 days later. IgG geometric means (GM) and medians were obtained, and modeled using ANCOVA and quantile regressions. RESULTS: The GM of IgG levels increased significantly after boosting: from 28.5±5.0 AU/mL up to 486.6±1.2 AU/mL (p<0.001) which corresponds to a 17-fold increase. The heterologous vaccine regimen produced higher GM of post-booster anti-SARS-CoV-2 IgG levels, eliciting a 13% increase in the geometric mean ratio (95%CI: 1.02-1.27) and a median difference of 92.3 AU/ml (95%CI: 24.9-159.7). Both vaccine regimens were safe and well tolerated. Previous COVID-19 infection was also associated with higher pre and post-booster IgG GM levels. CONCLUSION: Although both boosting regimens were highly immunogenic, two doses of BBIBP-CorV boosted with BTN162b2 produced a stronger IgG antibody response than the homologous BNT162b2 regimen in the Peruvian population. Additionally, both regimens were mildly reactogenic and well-tolerated.

Original languageEnglish
Article numbere0268419
Pages (from-to)e0268419
JournalPLoS ONE
Issue number10
StatePublished - Oct 2022
Externally publishedYes


  • Aged
  • Antibodies, Viral
  • BNT162 Vaccine
  • COVID-19/prevention & control
  • COVID-19 Vaccines/adverse effects
  • Humans
  • Immunization, Secondary
  • Immunogenicity, Vaccine
  • Immunoglobulin G
  • Peru
  • Prospective Studies
  • Vaccines, Synthetic
  • mRNA Vaccines


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