Omicron extensively but incompletely escapes Pfizer BNT162b2 neutralization

Sandile Cele, Laurelle Jackson, David S. Khoury, Khadija Khan, Thandeka Moyo-Gwete, Houriiyah Tegally, James Emmanuel San, Deborah Cromer, Cathrine Scheepers, Daniel G. Amoako, Farina Karim, Mallory Bernstein, Gila Lustig, Derseree Archary, Muneerah Smith, Yashica Ganga, Zesuliwe Jule, Kajal Reedoy, Shi Hsia Hwa, Jennifer GiandhariJonathan M. Blackburn, Bernadett I. Gosnell, Salim S. Abdool Karim, Willem Hanekom, NGS-SA, COMMIT-KZN Team, Anne von Gottberg, Jinal N. Bhiman, Richard J. Lessells, Mahomed Yunus S. Moosa, Miles P. Davenport, Tulio de Oliveira, Penny L. Moore, Alex Sigal

Research output: Contribution to journalArticlepeer-review

268 Citations (Scopus)


The emergence of the SARS-CoV-2 variant of concern Omicron (Pango lineage B.1.1.529), first identified in Botswana and South Africa, may compromise vaccine effectiveness and lead to re-infections1. Here we investigated Omicron escape from neutralization by antibodies from South African individuals vaccinated with Pfizer BNT162b2. We used blood samples taken soon after vaccination from individuals who were vaccinated and previously infected with SARS-CoV-2 or vaccinated with no evidence of previous infection. We isolated and sequence-confirmed live Omicron virus from an infected person and observed that Omicron requires the angiotensin-converting enzyme 2 (ACE2) receptor to infect cells. We compared plasma neutralization of Omicron relative to an ancestral SARS-CoV-2 strain and found that neutralization of ancestral virus was much higher in infected and vaccinated individuals compared with the vaccinated-only participants. However, both groups showed a 22-fold reduction in vaccine-elicited neutralization by the Omicron variant. Participants who were vaccinated and had previously been infected exhibited residual neutralization of Omicron similar to the level of neutralization of the ancestral virus observed in the vaccination-only group. These data support the notion that reasonable protection against Omicron may be maintained using vaccination approaches.

Original languageEnglish
Pages (from-to)654-656, [1-11]
Number of pages14
Issue number7898
Early online date23 Dec 2021
Publication statusPublished - 24 Feb 2022
Externally publishedYes


  • COVID-19
  • SARS-CoV-2
  • Omicron variant
  • Vaccination
  • Pfizer BNT162b2


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