Antibody response to SARS-CoV-2 in infected patients with different clinical outcome

J Med Virol. 2021 Apr;93(4):2548-2552. doi: 10.1002/jmv.26789. Epub 2021 Jan 26.


Data regarding antibody responses to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in patients infected with COVID-19 are not yet available. In this study, we aimed to evaluate serum antibody responses in patients regardless of the outcome. We measured the circulating immunoglobulin G (IgG) antibody levels in 60 subjects with a certified history of SARS-CoV-2 infection by using immunoenzymatic, chemiluminescent, and Neutralization assays. Half patients had a severe infection, the other half were pauci-symptomatic. We analyzed their antibody response to see the trend of the humoral response. Our results showed a significant difference in circulating IgG level among the two groups. The neutralizing antibody response against SARS-CoV-2 was significantly higher among those who had severe disease. Furthermore, ten subjects from each group were screened twice, and a declining antibody trend was observed in pauci-symptomatic individuals. These findings provide evidence that humoral immunity against SARS-CoV-2 in pauci-symptomatic people is weak and may not be long-lasting. This may have implications for immunity strategy and prevention, since it is still not clear whether a time-dependent decrease of both circulating and neutralizing antibodies to nonprotective levels could occur in a longer time span and whether potential vaccines are able to induce a herd immunity and a durable response.

Keywords: coronavirus; humoral immunity; neutralization.

MeSH terms

  • Adult
  • Aged
  • Animals
  • Antibodies, Neutralizing / blood
  • Antibodies, Viral / biosynthesis*
  • Antibodies, Viral / blood*
  • Antibody Formation
  • COVID-19 / immunology
  • COVID-19 / virology*
  • Chlorocebus aethiops
  • Humans
  • Immunity, Humoral
  • Immunoglobulin G / blood
  • Immunoglobulin G / isolation & purification
  • Middle Aged
  • Neutralization Tests
  • SARS-CoV-2 / immunology*
  • Vero Cells


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Immunoglobulin G