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

Authors

  • Lucy Santos Villas-Boas Universidade de São Paulo
  • Anderson Vicente de Paula Universidade de São Paulo https://orcid.org/0000-0002-7919-3516
  • Almir Ribeiro da Silva Jr. Universidade de São Paulo https://orcid.org/0000-0001-7071-8243
  • Heuder Gustavo Oliveira Paiao Universidade de São Paulo https://orcid.org/0000-0002-4358-1146
  • Tania Regina Tozetto-Mendoza Universidade de São Paulo
  • Erika Regina Manuli Universidade de São Paulo
  • Fábio Eudes Leal Universidade Municipal de Sâo Caetano do Sul https://orcid.org/0000-0003-1986-3765
  • Andrea de Barros Coscelli Ferraz Universidade Municipal de Sao Caetano do Sul
  • Ester Cerdeira Sabino Universidade de São Paulo
  • Ana Luiza Bierrenbach Hospital Sírio-Libanês
  • Steven Sol Witkin Universidade de São Paulo
  • Maria Cassia Mendes-Correa Universidade de São Paulo

DOI:

https://doi.org/10.1016/j.clinsp.2022.100068

Keywords:

SARS-CoV-2, Omicron variant, Gamma variant, Neutralizing antibodies, Protective antibodies

Abstract

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.

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Published

2022-06-16

Issue

Section

Original Articles

How to Cite

Villas-Boas, L. S., Paula, A. V. de, Silva Jr., A. R. da, Paiao, H. G. O., Tozetto-Mendoza, T. R., Manuli, E. R., Leal, F. E., Ferraz, A. de B. C., Sabino, E. C., Bierrenbach, A. L., Witkin, S. S., & Mendes-Correa, M. C. (2022). 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. Clinics, 77, 100068. https://doi.org/10.1016/j.clinsp.2022.100068