Booster dose of BNT162b2 after two doses of CoronaVac improves neutralization of SARS-CoV-2 Omicron variant

Background: The emergence of the SARS-CoV-2 Omicron variant, with numerous mutations, raised concerns about vaccine escape, particularly reduced neutralization by vaccine-induced antibodies. Methods: Using viral microneutralization assays, antibody neutralization against Omicron was evaluated in 90 individuals who received a BNT162b2 mRNA booster after a two-dose CoronaVac primary series. Results: Seroconversion 30 and 60 days after the CoronaVac series was 16.6% and 10%, respectively. After the BNT162b2 booster, seroconversion increased to 76.6%, and the mean neutralization titer against Omicron increased 43.1-fold. Conclusions: A BNT162b2 booster following CoronaVac positively impacts the neutralizing antibody response against Omicron.

Guilherme R F Campos, Nathalie Bonatti Franco Almeida, Priscilla Soares Filgueiras, Camila Amorimno 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, Jaqueline Germano de Oliveira, Paula Raha, Rafaella Fortini Queiroz Grenfell, Maurício L Nogueira