Serology study after BTN162b2 vaccination in participants previously infected with SARS-CoV-2 in two different waves versus naïve

Abstract

Plain language summary Antibodies are proteins produced by the immune system that are released into the bloodstream and help fight infections. To understand how the immune system responds to COVID-19 vaccination in individuals who have had a previous SARS-CoV-2 infection, we compared the types and levels of antibodies produced after first and second doses of the vaccine with those of individuals who had never been infected. We found that one dose of vaccine, even several months after the infection, was sufficient to boost a very efficient response by eliciting specific types of antibodies, some of which were and some that were not able to neutralize the virus. We also observed an unusual antibody profile in almost half of individuals who had not been infected. These findings may help better understand the immune response to COVID-19 vaccines.