REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in May 2020
Published 15 July 2020
Applies to England
© Crown copyright 2020
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This publication is available at https://www.gov.uk/government/publications/react-1-study-of-coronavirus-transmission-may-2020-results/react-1-real-time-assessment-of-community-transmission-of-coronavirus-covid-19-in-may-2020
Methodology
A representative cross-section of volunteers tested themselves with swabs between 1 May and 1 June 2020. Swabs were analysed using polymerase chain reaction (PCR).
Results
Overall prevalence of infection in the community was 0.13% (0.11%,0.15%). Out of 120,610 swab results, 159 were positive.
This corresponds to an estimated 74,000 (63,000, 86,000) prevalent infections of SARS-CoV-2 on any average day during May 2020.
During May 2020 prevalence decreased by half every 8.6 days (6.2, 13.6).
The reproduction number R was estimated to be 0.57 (0.45, 0.72).
Among all key workers, the prevalence of infection was highest among care home workers 0.71% (0.24%, 2.06%), followed by health care workers 0.47% (0.30%, 0.75%) and then other key workers 0.17% (0.12%, 0.25%):
- a care home worker had odds of testing positive higher by a factor of 7.7 (1.8, 22)
- health care workers had odds higher by a factor of 5.2 (2.8, 9.2)
- other key workers had odds higher by a factor of 1.8 (1.1, 3.1)
Recent contact with a known COVID-19 case was associated with odds of 24 (16, 38) for swab-positivity and for contact with a suspected case 5.3 (2.2, 12).
Asian ethnicity was associated with unadjusted odds of 1.9 (1.0, 3.5) for swab positivity compared with white ethnicity. This reduced to 1.7 (0.86, 3.5) when adjusted for age and sex.
Rates of infection were highest at ages 18 to 24 years, 0.28% (0.18%, 0.43%), dropping to 0.07% (0.05%, 0.12%) in those aged 65 or above.
69% (61, 76) of participants who tested positive did not report any symptoms at the time of swabbing or in the previous 7 days.
Symptoms associated with a positive result compared to no reported symptoms were loss of sense of smell, loss of sense of taste, nausea, diarrhoea, chills, blocked nose, headache and severe fatigue.
Prevalence was highest in London at 0.20% (0.13%, 0.31%) and lowest in the South West at 0.06% (0.03%, 0.12%) but these differences were not significant, and no evidence of geographic clustering was found.
Conclusion
During May 2020, SARS-CoV-2 virus was circulating with relatively low prevalence and was declining.
Subsequent rounds of REACT-1 will allow accurate assessment of trends in prevalence after lockdown has been eased.
Background
Read the press notice accompanying these findings.
Read the pre-print version of the report.