Neutralizing antibodies against the SARS-CoV-2 Omicron variant BA.1 following homologous and heterologous CoronaVac or BNT162b2 vaccination

Abstract

This is a PDF file of a peer-reviewed paper that has been accepted for publication. Although unedited, the content has been subjected to preliminary formatting. Nature Medicine is providing this early version of the typeset paper as a service to our authors and readers. The text and figures will undergo copyediting and a proof review before the paper is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers apply.

Virus neutralization of SARS-CoV-2 Omicron variant BA.2 in those vaccinated with three doses of BNT162b2 or CoronaVac vaccines.

“…A RNA vaccine BioNTech-Pfizer (BNT162b2) and an inactivated whole virus vaccine CoronaVac are two of the most widely used COVID-19 vaccines globally, each with over 2 billion doses delivered so far 7 . We and others have shown that Omicron BA.1 is poorly neutralized by sera from individuals vaccinated with two doses of the BNT162b2 or CoronaVac 8,9 . A third dose of BNT162b2 vaccine was shown to increase neutralizing antibody titres in those previously vaccinated with two doses of BNT162b2 as well as in those vaccinated with CoronaVac.…”

“…The Omicon subvariant BA.2 virus (hCoV-19/Hong Kong/VM22000135_HKUVOC0588P2/2022) isolated in Hong Kong on 3 rd January 2022 was used for this study (GISAID EPI_ISL_9570707). The PRNT50 and PRNT90 data with the BA.2 virus derived from this study was compared with PRNT50 and PRNT90 data obtained for Omicron subvariant BA.1 and ancestral virus obtained for the respective sera previously reported (8) .…”

“…Clinical specimens: We randomly selected 20 sera from each of four cohorts used for a recently published comparative study of Omicron subvariant BA.1 neutralizing antibody responses 3-5 weeks after vaccination or 143-196 days after SARS-CoV-2 infection (8) . The Virology: Vero E6 cells overexpressing TMPRSS2 (kindly provided by Dr S Matsuyama and colleagues) (14) were used for virus isolation and plaque reduction neutralization tests (PRNT).…”

“…Plaque reduction neutralization tests were carried out in duplicate using 24-well tissue culture plates (TPP Techno Plastic Products AG, Trasadingen, Switzerland) in a biosafety level 3 facility using Vero E6 TMRESS cells described previously (8,15) . Serial two-fold dilutions from 1:10 to 1:320 of each serum sample was incubated with 30-40 plaque-forming units of…”

“…The sera were collected at day 143-196 after infection in the SARS-CoV-2 convalescent cohort and 3-5 weeks after the last vaccine dose in the three vaccine-cohorts 4 studied. These sera were tested to determine 50% plaque reduction neutralization test (PRNT50) and PRNT90 titres as previously described 8 (see methods) and data compared with previously reported data on those sera for the ancestral wild-type (WT) or Omicron BA.1 viruses 8 . BA.2 had markedly reduced PRNT50 antibody titers relative to WT virus but BA.1 and BA.2 viruses had PRNT50 titers within 4-fold of each other (Figure 1 A,B).…”