To measure the association between self-reported signs and symptoms and SARS-CoV-2 seropositivity.
Cross sectional study of three key worker groups.
Six acute NHS hospitals and two Police and Fire and Rescue sites in England.
Individuals were recruited from three streams: (A) Police and Fire and Rescue services (n=1147), (B) healthcare workers (n=1546) and (C) healthcare workers with previously positive virus detection (n=154).
Main outcome measures
Detection of anti-SARS-CoV-2 antibodies in plasma.
943 of the 2847 participants (33%) reported belief they had had COVID-19, having experienced compatible symptoms (including 152 from Stream C). Among individuals reporting COVID-19 compatible symptoms, 466 (49%) were seronegative on both Nucleoprotein (Roche) and Spike-protein (EUROIMMUN) antibody assays. However, among the 268 individuals with prior positive SARS-CoV-2 tests, of whom 96% reported symptoms with onset a median of 63 days (IQR 52 to 75 days) prior to venesection, Roche and EUROIMMUN assays had 96.6% (95% CI 93.7% to 98.2%) and 93.3% (95% CI 89.6% to 95.7%) sensitivity respectively. Symptomatic but seronegative individuals had significantly earlier symptom onset dates than the symptomatic seropositive individuals, shorter illness duration and a much lower anosmia reporting frequency.
Self-reported belief of COVID-19 was common among our frontline worker cohort. About half of these individuals were seronegative, despite a high sensitivity of serology in this cohort, at least in individuals with previous positive PCR results. This is compatible with non-COVID-19 respiratory disease during the COVID-19 outbreak having been commonly mistaken for COVID-19 within the key worker cohort studied.
Competing Interest Statement
The authors have declared no competing interest.
The study was funded by Public Health England and supported by the NIHR Clinical Research Network (CRN) Portfolio.
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The study was approved by NHS Research Ethics Committee (Health Research Authority, IRAS 284980) on 02/06/2020 and PHE Research Ethics and Governance Group (REGG, NR0198) on 21/05/2020.
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