Alliance for Pandemic Preparedness

April 30, 2021

Previously Infected Vaccinees Broadly Neutralize SARS-CoV-2 Variants



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  • [Pre-print, not peer-reviewed] A small study of sera from patients vaccinated with the Pfizer-BioNTech vaccine (N=30) found similar levels of anti-SARS-CoV-2 spike antibodies in persons with and without previous documentation of SARS-CoV-2 infection. Additionally, post-vaccination sera from previously infected persons demonstrated higher neutralizing activity in in-vitro against B.1.1.7, B.1.351 and P.1 compared to previously uninfected persons. There was no significant difference between the post-vaccination neutralizing antibody titers of previously infected participants against B.1.351 and those of uninfected participants against wildtype SARS-CoV-2, suggesting that first-generation COVID-19 vaccines could retain efficacy against variants when administered following infection with wildtype SARS-CoV-2.

Leier et al. (Apr 29, 2021). Previously Infected Vaccinees Broadly Neutralize SARS-CoV-2 Variants. Pre-print downloaded Apr 30 from