Neutralizing antibody responses 300 days after SARS-CoV-2 infection and induction of high antibody titers after vaccination

Neutralizing antibodies against SARS-CoV-2 are important to protect against infection and/or disease. Using an assay todetect antibodies directed against the receptor binding domain (RBD) of SARS-CoV-2 Spike, we identified individuals withSARS-CoV-2 infection after an outbreak at a local health institution. All but one COVID-19 patient developed detectableanti-RBD antibodies and 77% had virus neutralizing antibody titers of>1:25. Antibody levels declined slightly over time.However, we still detected virus neutralizing antibody titers in 64% of the COVID-19 patients at>300 days after infection,demonstrating durability of neutralizing antibody levels after infection. Importantly, full COVID-19 vaccination of theseindividuals resulted in higher antibody titers compared to fully vaccinated individuals in the absence of prior infection.These data demonstrate long-lived antibody-mediated immunity after SARS-CoV-2 infection, and a clear benefit of twovaccine doses for recovered individuals