SARS-CoV-2 antibodies persist for at least 4 months: Iceland data

  • Gudbjartsson DF & al.
  • N Engl J Med
  • 1 Sep 2020

  • curated by Liz Scherer
  • Clinical Essentials
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  Takeaway

  • SARS-CoV-2 antibodies persist for at least 4 months, with higher levels in older persons and those with more severe illness.

Why this matters

  • The persistence of antibodies is promising, given that antibody seroprevalence may affect overall population susceptibility to a second COVID-19 wave.

Key results

  • 30,576 serum samples collected.
  • 1797 were SARS-CoV-2 PCR positive.
  • 91.1% (95% CI, 89.4%-92.6%) of those who recovered were seropositive.
  • In the 487 who had repeat antibody measurements, antibody levels increased during 2 months post-PCR-confirmed diagnosis, and then plateaued for 2 months.
  • 60.54% (1088/1797) were in quarantine when testing positive.
  • Household exposure was associated with seropositivity (OR, 5.2; 95% CI, 3.3-8.0) vs other exposure types for negative-PCR/untested quarantined persons (n=4222).
  • Overall, 26.6% of quarantined persons with household exposure were SARS-CoV-2 positive vs 5.0% without household exposure.
  • Being symptomatic vs asymptomatic was associated (ORs; 95% CIs) with:
    • Seropositivity: 3.2 (1.7-6.2). 
    • Testing PCR-positive: 18.2 (14.8-22.4).
  • SARS-CoV-2 antibody levels most strongly associated with older age, hospitalization, and disease severity.

Study design

  • Retrospective, population-based surveillance of SARS-CoV-2 antibody seroprevalence, durability in the Icelandic population.
  • Funding: None disclosed.

Limitations

  • Limited generalizability.
  • Study design.