REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in June 2020
Published 6 August 2020
© Crown copyright 2020
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Methodology
A representative cross-section of volunteers tested themselves with swabs between 19 June and 8 July 2020. Swabs were analysed using polymerase chain reaction (PCR).
Results
Overall prevalence of infection in the community was 0.077% (0.065%, 0.092%). Out of 159,199 swab results, 123 were positive. This was lower than the prevalence of 0.13% (0.11%, 0.15%) measured during May 2020. During the period 19 June to 8 July 2020 prevalence decreased by half every 8.7 (5.3, 23) which is very similar to the 8.6 days (6.2, 13.6) measured during May 2020.
The reproduction number R was estimated to be 0.58 (0.37, 0.82) which is very similar to that measured during May 2020 at 0.57 (0.45, 0.72).
Prevalence of infection in London remains higher than in other regions, despite falling from 0.20% (0.13%, 0.31%) in May 2020 to 0.15% (0.10%, 0.22%) between 19 June and 8 July 2020. Also spatial clustering of cases was observed in and around London in that positive cases were found to be closer to each other than were negative cases.
There were no significant differences between the prevalence of infection for key workers and non-key workers. This is different from May 2020 when care workers and healthcare workers had increased risk of infection compared with those who were not key workers.
Recent contact with a known COVID-19 case was associated with a higher prevalence at 1.69% (0.89, 3.18) and for contact with a suspected case at 0.16% (0.03, 0.90).
Black, Asian and other ethnicity was associated with higher prevalence of infection at 0.15%, 1.0% and 0.15% respectively compared with white ethnicity at 0.07%.
Following adjustment, no significant difference was found in the rates in infection within households of different sizes.
There were no significant differences in the rates of infection by age which is different to the May results where higher rates of infection were seen in the 8 to 24 years age group.
81% (73, 87) of participants who tested positive did not report any symptoms at the time of swabbing or in the previous 7 days. This is higher than the proportion testing positive without symptoms in May, at 69% (61, 76) and may reflect increased mainstream testing for those with symptoms.
Conclusion
During the period 19 June to 8 July 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 and transmission.
Background
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