Duration of Viral Nucleic Acid Shedding and Early Reinfection With Severe Respiratory Syndrome Coronavirus 2 in Healthcare Workers and First Responders

J Infect Dis. 2021 Dec 1;224(11):1873-1877. doi: 10.1093/infdis/jiab504.


We estimated the distributions of duration of SARS-CoV-2 nucleic acid shedding and time to reinfection among 137 persons with at least 2 positive nucleic acid amplification test (NAAT) results from March to September 2020. We analyzed gaps of varying length between subsequent positive and negative NAAT results and estimated a mean duration of nucleic acid shedding of 30.1 days (95% confidence interval [CI], 26.3-34.5). Mean time to reinfection was 89.1 days (95% CI, 75.3-103.5). Together, these indicate that a 90-day period between positive NAAT results can reliably define reinfection in immunocompetent persons although reinfection can occur at shorter intervals.

Keywords: SARS-CoV-2; infection; nucleic acid; reinfection; viral shedding.

MeSH terms

  • COVID-19*
  • Emergency Responders*
  • Health Personnel*
  • Humans
  • RNA, Viral
  • Reinfection*
  • SARS-CoV-2
  • Virus Shedding*


  • RNA, Viral