Antibodies to SARS-CoV-2 protect against re-infection during outbreaks in care homes, September and October 2020

Euro Surveill. 2021 Feb;26(5):2100092. doi: 10.2807/1560-7917.ES.2021.26.5.2100092.

Abstract

Two London care homes experienced a second COVID-19 outbreak, with 29/209 (13.9%) SARS-CoV-2 RT-PCR-positive cases (16/103 residents, 13/106 staff). In those with prior SARS-CoV-2 exposure, 1/88 (1.1%) individuals (antibody positive: 87; RT-PCR-positive: 1) became PCR-positive compared with 22/73 (30.1%) with confirmed seronegative status. After four months protection offered by prior infection against re-infection was 96.2% (95% confidence interval (CI): 72.7-99.5%) using risk ratios from comparison of proportions and 96.1% (95% CI: 78.8-99.3%) using a penalised logistic regression model.

Keywords: COVID-19 outbreak; care homes.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Viral / blood*
  • COVID-19 / blood
  • COVID-19 / immunology
  • COVID-19 / prevention & control*
  • COVID-19 Serological Testing
  • Disease Outbreaks / prevention & control*
  • Female
  • Humans
  • London
  • Male
  • Middle Aged
  • Nursing Homes / statistics & numerical data*
  • Pandemics
  • Reinfection / prevention & control*
  • Reverse Transcriptase Polymerase Chain Reaction
  • SARS-CoV-2 / genetics*
  • SARS-CoV-2 / isolation & purification
  • Whole Genome Sequencing

Substances

  • Antibodies, Viral