Naturally acquired SARS-CoV-2 immunity persists for up to 11 months following infection

De Giorgi, Valeria; West, Kamille A; Henning, Amanda N; Chen, Leonard N; Holbrook, Michael R; Gross, Robin; Liang, Janie; Postnikova, Elena; Trenbeath, Joni; Pogue, Sarah; Scinto, Tania; Alter, Harvey J; Cantilena, Cathy Conry

BACKGROUND: Characterizing the kinetics of the antibody response to SARS‐CoV‐2 is of critical importance to developing strategies that may mitigate the public health burden of COVID-19. We conducted a prospective, longitudinal analysis of COVID-19 convalescent plasma (CCP) donors at multiple time points over an 11-month period in order to determine how circulating antibody levels change over time following natural infection. METHODS: From April 2020 to February 2021, we enrolled 228 donors. At each study visit, subjects either donated plasma or had study samples drawn only. Anti-SARS-CoV-2 donor testing was performed using the VITROS® Anti-SARS-CoV-2 Total and IgG assays, and an in-house fluorescence reduction neutralization assay (FRNA). RESULTS: Anti-SARS-CoV-2 antibodies were identified in 97% of COVID-19 convalescent donors at initial presentation. In follow up analyses, of the 116 donors presenting for repeat timepoints, 91.4% of donors had detectable IgG levels up to 11 months post-symptom recovery, while 63% had detectable neutralizing titers, however, we observed that 25% of donors had neutralizing levels that dropped to an undetectable titer over time. CONCLUSION: Our data suggest that immunological memory is acquired in most individuals infected with SARS-CoV-2 and is sustained in a majority of patients for up to 11 months after recovery.