Neutralization of SARS-CoV-2 variants by convalescent and BNT162b2 vaccinated serum

TLDR

SARS‑CoV‑2 and its variants continue to infect hundreds of thousands daily despite effective vaccines. Understanding the protection levels conferred by vaccines against emerging variants is essential. The study evaluated neutralizing antibody titers in two demographically balanced cohorts of BNT162b2 recipients and COVID‑19 patients against wild‑type, B.1.1.7, and B.1.351. Both B.1.1.7 and B.1.351 show reduced neutralization by vaccinated serum, with B.1.351 also evading convalescent serum; variant‑specific anti‑spike antibody levels correlate with neutralization, indicating that these variants escape antibody‑mediated protection, potentially increasing reinfection or breakthrough risk.

Abstract

SARS-CoV-2 and its variants continue to infect hundreds of thousands every day despite the rollout of effective vaccines. Therefore, it is essential to understand the levels of protection that these vaccines provide in the face of emerging variants. Here, we report two demographically balanced cohorts of BNT162b2 vaccine recipients and COVID-19 patients, from which we evaluate neutralizing antibody titers against SARS-CoV-2 as well as the B.1.1.7 (alpha) and B.1.351 (beta) variants. We show that both B.1.1.7 and B.1.351 are less well neutralized by serum from vaccinated individuals, and that B.1.351, but not B.1.1.7, is less well neutralized by convalescent serum. We also find that the levels of variant-specific anti-spike antibodies are proportional to neutralizing activities. Together, our results demonstrate the escape of the emerging SARS-CoV-2 variants from neutralization by serum antibodies, which may lead to reduced protection from re-infection or increased risk of vaccine breakthrough.