BACKGROUND AND PURPOSE:

• Patel et al. (JAMA, 2020) assessed the duration of antibody response to SARS-CoV-2 infection in health care personnel

METHODS:

• Participants
  • Healthcare personnel at a single medical center who regularly had direct contact with adult COVID-19 patients
• Study design
  • Surveys included symptom data starting February 1, 2020
  • Serological testing (against the SARS-CoV-2 spike protein)
    • Baseline visit: Between April 3 and April 13, 2020
    • 60-day visit: Between June 2 and June 27, 2020
  • The authors evaluated the following
    • Seropositive at baseline
    • Seropositive vs seronegative at 60 days

RESULTS:

• 230 healthcare personnel had two serological tests performed
  • 64.5% female | 91.6% white | Median (range) age 33 (21 to 70) years
• Participant demographics
  • Nurses: 42.2%
  • Physicians and advanced practice clinicians: 34.5%
  • Radiology technicians: 6.8%
  • Other: 16.5%
• Seropositivity
  • Seropositive at baseline: 7.6% (19 participants)
    • Seropositive at 60 days: 42% (8 participants)
    • Seronegative at 60 days: 58% (11 participants)
  • Overall seropositivity
    • At baseline: 7.6%
    • At 60-days: 3.2%
  • Of those who remained seropositive at 60 days, 75% reported symptoms prior to the baseline test
    • Of those who lost seropositivity at 60 days, 45% reported symptoms prior to the baseline test
• All participants who were seropositive at baseline had antibody decreases at 60 days
  • Participants who remained seropositive at 60 days had a higher signal-to-threshold ratios at baseline than those who lost seropositivity
    • Remained seropositive: mean (range) 4.8 (1.9 to 6.2)
    • No longer seroposi: mean (range) 1.4 (1.1 to 2.3)

CONCLUSION:

• Antibody levels against SARS-CoV-2 spike protein decreased over 60 days in healthcare personnel
  • 58% of those who were seropositive at baseline were seronegative at 60 days
• Declines in signal-to-noise ratios data support a true decline in antibody levels
• If replicable, the results have the following clinical implications  
  • Seroprevalence rates may underestimate true infection rates
  • The window in which people can donate serum for therapy may be limited
  • Whether this decline in antibody levels increases risk of reinfection is unknown

Learn More – Primary Sources:

Change in Antibodies to SARS-CoV-2 Over 60 Days Among Health Care Personnel in Nashville, Tennessee

Related ObG Topics:

SARS-CoV-2 Antibody Testing Among NYC Healthcare Personnel: How Many are Seropositive?

How Long Does It Take for COVID-19 Patients to Develop Antibodies?

RCT Results: Convalescent Plasma for the Treatment of COVID-19