Naturally Acquired SARS-CoV-2 Immunity Persists for Up to 11 Months Following Infection

J Infect Dis. 2021 Oct 28;224(8):1294-1304. doi: 10.1093/infdis/jiab295.


Background: Characterizing the kinetics of the antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is of critical importance to developing strategies that may mitigate the public health burden of coronavirus disease 2019 (COVID-19). We conducted a prospective, longitudinal analysis of COVID-19 convalescent plasma donors at multiple time points over an 11-month period 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.

Results: Anti-SARS-CoV-2 antibodies were identified in 97% of COVID-19 convalescent donors at initial presentation. In follow-up analyses, of 116 donors presenting at repeat time points, 91.4% had detectable IgG levels up to 11 months after symptom recovery, while 63% had detectable neutralizing titers; however, 25% of donors had neutralizing levels that dropped to an undetectable titer over time.

Conclusions: 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. Clinical Trials Registration. NCT04360278.

Keywords: COVID-19; convalescent plasma; immunological memory; neutralizing; serology.

Publication types

  • Observational Study
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptive Immunity*
  • Adolescent
  • Adult
  • Aged
  • Antibodies, Neutralizing / blood*
  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / blood*
  • Antibodies, Viral / immunology
  • COVID-19 / blood
  • COVID-19 / diagnosis
  • COVID-19 / immunology*
  • COVID-19 / virology
  • Convalescence
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Prospective Studies
  • SARS-CoV-2 / immunology*
  • SARS-CoV-2 / isolation & purification
  • Time Factors
  • Young Adult


  • Antibodies, Neutralizing
  • Antibodies, Viral

Associated data