Abstract
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.
Highlights
This is a PDF file of a peer-reviewed paper that has been accepted for publication
We investigated whether Omicron escapes antibody neutralization in South Africans
Geometric mean titer (GMT) FRNT50 for all participants declined from 1963 to 89, a 22-fold drop (Fig. 1d, 95% CI 16-30)
Summary
This is a PDF file of a peer-reviewed paper that has been accepted for publication. unedited, the content has been subjected to preliminary formatting. South Africa, may compromise vaccine effectiveness and lead to re-infections[1]. C relative to an ancestral SARS-CoV-2 strain, observing that Omicron still required ACE2 I to infect.
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