Considerable escape of SARS-CoV-2 Omicron to antibody neutralization

Nature. 2022 Feb;602(7898):671-675. doi: 10.1038/s41586-021-04389-z. Epub 2021 Dec 23.


The SARS-CoV-2 Omicron variant was first identified in November 2021 in Botswana and South Africa1-3. It has since spread to many countries and is expected to rapidly become dominant worldwide. The lineage is characterized by the presence of around 32 mutations in spike-located mostly in the N-terminal domain and the receptor-binding domain-that may enhance viral fitness and enable antibody evasion. Here we isolated an infectious Omicron virus in Belgium from a traveller returning from Egypt. We examined its sensitivity to nine monoclonal antibodies that have been clinically approved or are in development4, and to antibodies present in 115 serum samples from COVID-19 vaccine recipients or individuals who have recovered from COVID-19. Omicron was completely or partially resistant to neutralization by all monoclonal antibodies tested. Sera from recipients of the Pfizer or AstraZeneca vaccine, sampled five months after complete vaccination, barely inhibited Omicron. Sera from COVID-19-convalescent patients collected 6 or 12 months after symptoms displayed low or no neutralizing activity against Omicron. Administration of a booster Pfizer dose as well as vaccination of previously infected individuals generated an anti-Omicron neutralizing response, with titres 6-fold to 23-fold lower against Omicron compared with those against Delta. Thus, Omicron escapes most therapeutic monoclonal antibodies and, to a large extent, vaccine-elicited antibodies. However, Omicron is neutralized by antibodies generated by a booster vaccine dose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antibodies, Monoclonal / immunology
  • Antibodies, Neutralizing / immunology*
  • Antibodies, Viral / immunology*
  • BNT162 Vaccine / administration & dosage
  • BNT162 Vaccine / immunology
  • Belgium
  • COVID-19 / immunology
  • COVID-19 / transmission
  • COVID-19 / virology*
  • ChAdOx1 nCoV-19 / administration & dosage
  • ChAdOx1 nCoV-19 / immunology
  • Convalescence
  • Female
  • Humans
  • Immune Evasion / immunology*
  • Immunization, Secondary*
  • Male
  • Mutation
  • Neutralization Tests
  • Phylogeny
  • SARS-CoV-2 / classification
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / immunology*
  • SARS-CoV-2 / isolation & purification
  • Travel


  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • ChAdOx1 nCoV-19
  • BNT162 Vaccine

Supplementary concepts

  • SARS-CoV-2 variants