SARS-CoV-2 Omicron triggers cross-reactive neutralization and Fc effector functions in previously vaccinated, but not unvaccinated individuals

• DOI: 10.1101/2022.02.10.22270789
• Publication Date: 2022-02-14T21:25:21Z
• Authors: Simone I Richardson; Vimbai Sharon Mad...; Holly Spencer; Nelia P Manamela; Mieke van der Mescht; Bronwen E Lambson; Brent Oosthuysen; Frances Ayres; Zanele Makhado; Thandeka Moyo-Gwete; Nonkululeko Mzindle; Thopisang Motlou; Amy Strydom; Adriano Mendes; Houriiyah Tegally; Zelda de Beer; Talita Roma de Vi...; Annie Bodenstein; Gretha van den Berg; Marietjie Venter; Tulio de Oliviera; Veronica Ueckermann; Theresa M Rossouw; Michael T Boswell; Penny L Moore
• Keywords: 360; 0301 basic medicine; Vaccines; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); Brief Report; COVID-19; Omicron variant; Antibodies, Viral; Antibodies, Neutralizing; 3. Good health; Variants of concern (VOCs); 03 medical and health sciences; Neutralization Tests; Humans; Infection

The SARS-CoV-2 Omicron variant escapes neutralizing antibodies elicited by vaccines or infection. However, whether triggers cross-reactive humoral responses to other variants of concern (VOCs) remains unknown. We use plasma from 20 unvaccinated and seven vaccinated individuals infected BA.1 test binding, Fc effector function neutralization against VOCs. In individuals, binding target VOCs at comparable levels. BA.1-triggered is not extensively for (14 31-fold titer reduction) we observe 4-fold decreased titers BA.2. contrast, vaccination followed breakthrough infection was associated with improved cross-neutralization VOCs, exceeding 1:2,100. This has important implications vulnerability Omicron-infected reinfection circulating emerging While Omicron-based immunogens may be adequate boosters, they are unlikely superior existing priming in naive individuals.