SARS-CoV-2 antibody detection in skilled nursing facility residents

J Am Geriatr Soc. 2021 Jul;69(7):1722-1728. doi: 10.1111/jgs.17061. Epub 2021 Feb 21.

Abstract

Objective: To describe the frequency and timing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody detection in a convenience sample of skilled nursing facility (SNF) residents with and without confirmed SARS-CoV-2 infection.

Design: Retrospective analysis of SNF electronic health records.

Setting: Qualitative SARS-CoV-2 antibody test results were available from 81 SNFs in 16 states.

Participants: Six hundred and sixty nine SNF residents who underwent both polymerase chain reaction (PCR) and antibody testing for SARS-CoV-2.

Measurements: Presence of SARS-CoV-2 antibodies following the first positive PCR test for confirmed cases, or first PCR test for non-cases.

Results: Among 397 residents with PCR-confirmed infection, antibodies were detected in 4 of 7 (57.1%) tested within 7-14 days of their first positive PCR test; in 44 of 47 (93.6%) tested within 15-30 days; in 182 of 219 (83.1%) tested within 31-60 days; and in 110 of 124 (88.7%) tested after 60 days. Among 272 PCR negative residents, antibodies were detected in 2 of 9 (22.2%) tested within 7-14 days of their first PCR test; in 41 of 81 (50.6%) tested within 15-30 days; in 65 of 148 (43.9%) tested within 31-60 days; and in 9 of 34 (26.5%) tested after 60 days. No significant differences in baseline resident characteristics or symptoms were observed between those with versus without antibodies.

Conclusions: These findings suggest that vulnerable older adults can mount an antibody response to SARS-CoV-2, and that antibodies are most likely to be detected within 15-30 days of diagnosis. That antibodies were detected in a large proportion of residents with no confirmed SARS-CoV-2 infection highlights the complexity of identifying who is infected in real time. Frequent surveillance and diagnostic testing based on low thresholds of clinical suspicion for symptoms and/or exposure will remain critical to inform strategies designed to mitigate outbreaks in SNFs while community SARS-CoV-2 prevalence remains high.

Keywords: COVID19; SARS-CoV-2; nursing home; serology; skilled nursing facility.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Asymptomatic Infections / epidemiology
  • COVID-19 Nucleic Acid Testing / statistics & numerical data
  • COVID-19 Serological Testing / methods*
  • COVID-19* / blood
  • COVID-19* / diagnosis
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Early Diagnosis
  • Electronic Health Records / statistics & numerical data
  • Female
  • Health Services Needs and Demand
  • Humans
  • Male
  • Prevalence
  • SARS-CoV-2* / immunology
  • SARS-CoV-2* / isolation & purification
  • Skilled Nursing Facilities* / standards
  • Skilled Nursing Facilities* / statistics & numerical data
  • Symptom Assessment / methods
  • Symptom Assessment / statistics & numerical data
  • United States / epidemiology