High genetic barrier to SARS-CoV-2 polyclonal neutralizing antibody escape.

The number and variability of the neutralizing epitopes targeted by polyclonal antibodies in individuals who are SARS-CoV-2 convalescent and vaccinated are key determinants of neutralization breadth and the genetic barrier to viral escape. Using HIV-1 pseudotypes and plasma selection experiments with vesicular stomatitis virus/SARS-CoV-2 chimaeras, here we show that multiple neutralizing epitopes, within and outside the receptor-binding domain, are variably targeted by human polyclonal antibodies. Antibody targets coincide with spike sequences that are enriched for diversity in natural SARS-CoV-2 populations.

Vaccine Breakthrough Infections with SARS-CoV-2 Variants.

Emerging variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are of clinical concern. In a cohort of 417 persons who had received the second dose of BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine at least 2 weeks previously, we identified 2 women with vaccine breakthrough infection. Despite evidence of vaccine efficacy in both women, symptoms of coronavirus disease 2019 developed, and they tested positive for SARS-CoV-2 by polymerase-chain-reaction testing.