Absence of neutralizing antibodies against the Omicron SARS-CoV-2 variant in convalescent sera from individuals infected with the ancestral SARS-CoV-2 virus or its Gamma variant

• Autor(a) principal: Villas-Boas, Lucy Santos
• Data de Publicação: 2022
• Outros Autores: Paula, Anderson Vicente de, Silva Jr., Almir Ribeiro da, Paiao, Heuder Gustavo Oliveira, Tozetto-Mendoza, Tania Regina, Manuli, Erika Regina, Leal, Fábio Eudes, Ferraz, Andrea de Barros Coscelli, Sabino, Ester Cerdeira, Bierrenbach, Ana Luiza, Witkin, Steven Sol, Mendes-Correa, Maria Cassia
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Clinics
• Texto Completo: https://www.revistas.usp.br/clinics/article/view/213419
• topic: SARS-CoV-2; Omicron variant; Gamma variant; Neutralizing antibodies; Protective antibodies

Objectives: The aim of the present study was to evaluate if neutralizing antibody responses induced by infection with the SARS-CoV-2 strain that was dominant at the beginning of the pandemic or by the Gamma variant was effective against the Omicron variant. Methods: Convalescent sera from 109 individuals, never exposed to a SARS-CoV-2 vaccine, who had mild or moderate symptoms not requiring hospitalization following either a documented SARS-CoV-2 ancestral strain infection or a Gamma variant infection, were assayed for in vitro neutralizing antibody activity against their original strains and the Omicron variant. Results: Following an infection with the ancestral strain, 56 (93.3%), 45 (77.6%) and 1 (1.7%) serum sample were positive for neutralizing antibodies against the ancestral, Gamma variant, and Omicron variant, respectively. After infection with the Gamma variant, 43 (87.8%) and 2 (4.1%) sera were positive for neutralizing antibodies against the Gamma and Omicron variants, respectively. Conclusions: Neutralizing antibodies generated following mild or moderate infection with the SARS-CoV-2 ancestral strain or the Gamma variant are not protective against the Omicron variant.