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ERJ Open Res
. 2021 Jun 7;7(2):00080-2021.
doi: 10.1183/23120541.00080-2021. eCollection 2021 Apr.
The protective effect of SARS-CoV-2 antibodies in Scottish healthcare workers
Hani Abo-Leyah 1 , Stephanie Gallant 1 , Diane Cassidy 1 , Yan Hui Giam 1 , Justin Killick 2 , Beth Marshall 2 , Gordon Hay 2 , Caroline Snowdon 3 , Eleanor J Hothersall 3 , Thomas Pembridge 1 , Rachel Strachan 1 , Natalie Gallant 1 , Benjamin J Parcell 4 , Jacob George 1 , Elizabeth Furrie 2 5 , James D Chalmers 1 5
Affiliations
- PMID: 34104643
- PMCID: PMC8164012
- DOI: 10.1183/23120541.00080-2021
Abstract
Background: Healthcare workers (HCWs) are believed to be at increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. It is not known to what extent the natural production of antibodies to SARS-CoV-2 is protective against re-infection.
Methods: A prospective observational study of HCWs in Scotland (UK) from May to September 2020 was performed. The Siemens SARS-CoV-2 total antibody assay was used to establish seroprevalence in this cohort. Controls, matched for age and sex to the general local population, were studied for comparison. New infections (up to 2 December 2020) post antibody testing were recorded to determine whether the presence of SARS-CoV-2 antibodies protects against re-infection.
Results: A total of 2063 health and social care workers were recruited for this study. At enrolment, 300 HCWs had a positive antibody test (14.5%). 11 out of 231 control sera tested positive (4.8%). HCWs therefore had an increased likelihood of a positive test (OR 3.4, 95% CI 1.85-6.16; p<0.0001). Dentists were most likely to test positive. 97.3% of patients who had previously tested positive for SARS-CoV-2 by reverse transcriptase (RT)-PCR had positive antibodies. 18.7% had an asymptomatic infection. There were 38 new infections with SARS-CoV-2 in HCWs who were previously antibody negative, and one symptomatic RT-PCR-positive re-infection. The presence of antibodies was therefore associated with an 85% reduced risk of re-infection with SARS-CoV-2 (hazard ratio 0.15, 95% CI 0.06-0.35; p=0.026).
Conclusion: HCWs were three times more likely to test positive for SARS-CoV-2 than the general population. Almost all infected individuals developed an antibody response, which was 85% effective in protecting against re-infection with SARS-CoV-2.