Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine–elicited human sera

Abstract

The globally circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern Omicron (B.1.1.529) has a large number of mutations, especially in the spike protein, indicating that recognition by neutralizing antibodies may be compromised. We tested Wuhan (Wuhan-Hu-1 reference strain), Beta (B.1.351), Delta (B.1.617.2), or Omicron pseudoviruses with sera of 51 participants who received two or three doses of the messenger RNA (mRNA)–based COVID-19 vaccine BNT162b2. After two doses, Omicron-neutralizing titers were reduced >22-fold compared with Wuhan-neutralizing titers. One month after the third vaccine dose, Omicron-neutralizing titers were increased 23-fold relative to their levels after two doses and were similar to levels of Wuhan-neutralizing titers after two doses. The requirement of a third vaccine dose to effectively neutralize Omicron was confirmed with sera from a subset of participants using live SARS-CoV-2. These data suggest that three doses of the mRNA vaccine BNT162b2 may protect against Omicron-mediated COVID-19.

Differential Dynamics of SARS-CoV-2 Binding and Functional Antibodies upon BNT162b2 Vaccine: A 6-Month Follow-Up

“…Longer follow-up studies on the waning of humoral response and on the effect of booster doses are also ongoing in our hospital. Furthermore, preliminary results of experiments aimed at evaluating in vitro vaccine protection against SARS-CoV-2 variants of concern, are in line with published research articles showing a decay in the neutralization levels when using Delta or Omicron strains [30][31][32].…”

Boosting immunity to Omicron

“…Crucially, however, a BNT162b2 booster after either regimen increased the response rate against Omicron -to 100% if given after BNT162b2 primary immunization 3,4 and to more than 90% if given after CoronaVac 3 . The levels of neutralizing antibodies against Omicron were improved 7-to 100-fold with an mRNA booster, so that they were ultimately within 2-fold of the level of response against ancestral Wuhan-1 in all three studies, which is consistent with other reports 8 . Because neutralizing antibody levels have tended to correlate with COVID-19 vaccine-mediated protection 9 , it is reasonable to expect similar levels of protection against Omicron after an mRNA booster to that seen against earlier variants after two vaccine doses.…”

Antibody Responses after SARS-CoV-2 Vaccination in Patients with Liver Diseases

“…Thirdly, vaccine-induced cellular immunity against SARS-CoV-2 was not investigated. Fourthly, as new SARS-CoV-2 variants of concern demonstrate mutations particularly in the spike protein, their recognition by neutralizing antibodies from vaccinated individuals may be compromised [40]. Finally, the identification of SARS-CoV-2 post-vaccination breakthrough infections was based on self-reporting.…”