European Journal of General Practice (Dec 2023)

Prevalence of SARS-CoV-2 antibodies among Belgian nursing home residents and staff during the primary COVID-19 vaccination campaign

  • Eline Meyers,
  • Liselore De Rop,
  • Ellen Deschepper,
  • Els Duysburgh,
  • Tine De Burghgraeve,
  • Pauline Van Ngoc,
  • Marina Digregorio,
  • Simon Delogne,
  • Anja Coen,
  • Nele De Clercq,
  • Laëtitia Buret,
  • Samuel Coenen,
  • An De Sutter,
  • Beatrice Scholtes,
  • Jan Y. Verbakel,
  • Piet Cools,
  • Stefan Heytens

DOI
https://doi.org/10.1080/13814788.2022.2149732
Journal volume & issue
Vol. 29, no. 2

Abstract

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AbstractBackground Nursing home residents (NHR) and staff have been disproportionally affected by the COVID-19 pandemic and were therefore prioritised in the COVID-19 vaccination strategy. However, frail older adults, like NHR, are known to have decreased antibody responses upon vaccination targeting other viral antigens.Objectives As real-world data on vaccine responsiveness, we assessed the prevalence of SARS-CoV-2 antibodies among Belgian NHR and staff during the primary COVID-19 vaccination campaign.Methods In total, we tested 1629 NHR and 1356 staff across 69 Belgian NHs for the presence of SARS-CoV-2 IgM/IgG antibodies using rapid tests. We collected socio-demographic and COVID-19-related medical data through questionnaires. Sampling occurred between 1 February and 24 March 2021, in a randomly sampled population that received none, one or two BNT162b2 vaccine doses.Results We found that during the primary vaccination campaign with 59% of the study population fully vaccinated, 74% had SARS-CoV-2 antibodies. Among fully vaccinated individuals only, fewer residents tested positive for SARS-CoV-2 antibodies (77%) than staff (98%), suggesting an impaired vaccine-induced antibody response in the elderly, with lowest seroprevalences observed among infection naïve residents. COVID-19 vaccination status and previous SARS-CoV-2 infection were predictors for SARS-CoV-2 seropositivity. Alternatively, age ≥ 80 years old, the presence of comorbidities and high care dependency predicted SARS-CoV-2 seronegativity in NHR.Conclusion These findings highlight the need for further monitoring of SARS-CoV-2 immunity upon vaccination in the elderly population, as their impaired humoral responses could imply insufficient protection against COVID-19.Trial registration This study was retrospectively registered on ClinicalTrials.gov (NCT04738695).

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