Booster dose of BNT162b2 after two doses of CoronaVac improves neutralization of SARS-CoV-2 Omicron variant
Guilherme Rodrigues Fernandes Campos, Nathalie Bonatti Franco Almeida, Priscilla Soares Filgueiras, Camila Amormino Corsini, Sarah Vieira Contin Gomes, Daniel Alvim Pena de Miranda, Jéssica Vieira de Assis, Thaís Bárbara de Souza Silva, Pedro Augusto Alves, Gabriel da Rocha Fernandes, Jaquelline Germano de Oliveira, Paula Rahal, Rafaella Fortini Queiroz Grenfell, Maurício Lacerda Nogueira
Abstract
Background: The emergence of the new SARS-CoV-2 Omicron variant, which is known to have a large number of mutations when compared to other variants, brought to light the concern about vaccine escape, especially from the neutralization by antibodies induced by vaccination. Methods: Based on viral microneutralization assays, we evaluated in 90 individuals the impact on antibody neutralization induction, against Omicron variant, by a booster dose of BNT162b2 mRNA vaccine after the CoronaVac primary vaccination scheme. Results: Here we show that the percentage of seroconverted individuals 30 and 60 days after CoronaVac scheme was 16.6% and 10%, respectively. After booster dose administration, the seroconvertion rate increased to 76.6%. The neutralization mean titer against Omicron in the CoronaVac protocol decreased over time, but after the booster dose, the mean titer increased 43.1 times. Conclusions: These results indicate a positive impact of this vaccine combination in the serological immune response against SARS-CoV-2 Omicron variant.