In this study the authors investigated whether Omicron escapes antibody neutralization in South Africans vaccinated with Pfizer BNT162b2. They also investigated if Omicron requires the ACE2 receptor to infect cells. Confirmed live Omicron virus from an infected person in South Africa was isolated and sequence and compared plasma neutralization of Omicron relative to an ancestral SARS-CoV-2 strain, observing that Omicron still required ACE2 to infect. For neutralization, blood samples were taken soon after vaccination from participants who were vaccinated and previously infected or vaccinated with no evidence of previous infection. Neutralization of ancestral virus was much higher in infected and vaccinated versus vaccinated only participants but both groups showed a 22-fold escape from vaccine elicited neutralization by the Omicron variant. However, in the previously infected and vaccinated group, the level of residual neutralization of Omicron was similar to the level of neutralization of ancestral virus observed in the vaccination only group. These data support the notion that, provided high neutralization capacity is elicited by vaccination/boosting approaches, reasonable effectiveness against Omicron may be maintained.
Sandile Cele , Laurelle Jackson , David S. Khoury , Khadija Khan , Thandeka Moyo-Gwete , Houriiyah Tegally , James Emmanuel San , Deborah Cromer , Cathrine Scheepers , Daniel Amoako , Farina Karim , Mallory Bernstein , Gila Lustig , Derseree Archary , Muneerah Smith , Yashica Ganga , Zesuliwe Jule , Kajal Reedoy , Shi-Hsia Hwa , Jennifer Giandhari , Jonathan M. Blackburn , Bernadett I. Gosnell , Salim S. Abdool Karim , Willem Hanekom , Network for Genomic Surveillance in South Africa , COMMIT-KZN Team , Anne von Gottberg , Jinal Bhiman , Richard J. Lessells , Mahomed-Yunus S. Moosa , Miles P. Davenport , Tulio de Oliveira , Penny L. Moore & Alex Siga. Omicron extensively but incompletely escapes Pfizer BNT162b2 neutralization. Nature.
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Cross-sectional case-control studies