Viral dynamics and antibody responses in people with asymptomatic SARS-CoV-2 infection

Signal Transduct Target Ther. 2021 May 10;6(1):181. doi: 10.1038/s41392-021-00596-2.


Over 40% of the coronavirus disease 2019 (COVID-19) COVID-19 patients were asymptomatically infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the immune responses of these asymptomatic individuals is a critical factor for developing the strategy to contain the COVID-19 pandemic. Here, we determined the viral dynamics and antibody responses among 143 asymptomatic individuals identified in a massive screening of more than 5 million people in eight districts of Wuhan in May 2020. Asymptomatic individuals were admitted to the government-designated centralized sites in accordance with policy. The incidence rate of asymptomatic infection is ~2.92/100,000. These individuals had low viral copy numbers (peaked at 315 copies/mL) and short-lived antibody responses with the estimated diminish time of 69 days. The antibody responses in individuals with persistent SARS-CoV-2 infection is much longer with the estimated diminish time of 257 days. These results imply that the immune responses in the asymptomatic individuals are not potent enough for preventing SARS-CoV-2 re-infection, which has recently been reported in recovered COVID-19 patients. This casts doubt on the efficacy of forming "herd-immunity" through natural SARS-CoV-2 infection and urges for the development of safe and effective vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antibodies, Viral / blood
  • Antibodies, Viral / genetics
  • Antibodies, Viral / immunology*
  • Asymptomatic Infections / epidemiology*
  • COVID-19 / blood
  • COVID-19 / immunology*
  • COVID-19 / physiopathology
  • COVID-19 / virology
  • China / epidemiology
  • Female
  • Humans
  • Immunity / immunology*
  • Male
  • Middle Aged
  • Pandemics
  • SARS-CoV-2 / immunology
  • SARS-CoV-2 / pathogenicity


  • Antibodies, Viral