REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in July 2020
Published 11 September 2020
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Methodology
A representative cross-section of volunteers tested themselves with swabs between 24 July and 11 August 2020. Swabs were analysed using polymerase chain reaction (PCR).
Results
Overall adjusted prevalence of infection in the community was 0.04% (0.027%, 0.053%. This was adjusted for age, sex, ethnicity, region and area deprivation. Out of 161,560 swab results, 54 were positive. This was lower than the adjusted prevalence of 0.088% (0.068%, 0.109%) measured during June 2020.
During the period 24 July to 11 August 2020 prevalence doubled every 14.2 (-58.6, 6.4) days which is very different to the picture during June 2020 where the prevalence was decreasing by half every 8.7 (5.3, 21.0) days.
The reproduction number R was estimated to be 1.3 (0.9, 1.8) which is higher than that measured during June 2020 at 0.6 (0.4, 0.8).
Prevalence of infection was highest in Yorkshire and the Humber, the North West and London at 0.05% (0.03%, 0.12%), 0.5% (0.03%, 0.09%) and 0.05% (0.02, 0.10%) respectively. It was lowest in the South West, South East and North East at 0.20% (0.01%, 0.06%), 0.20% (0.01%, 0.04% and 0.02% (0.00%, 0.10%) respectively, but there were no significant differences by Region.
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 (confirmed by test) was associated with a higher prevalence at 0.85% (0.29%, 2.45%) than for no contact with a COVID-19 case at 0.03% (0.02%, 0.04%).
Black, Asian and other ethnicity was associated with higher prevalence of infection at 0.10%, 0.07% and 0.07% respectively compared with white ethnicity at 0.03%.
The highest rates of infection were 0.08% (0.04%, 0.18%) in young adults aged 18 to 24 years followed by 0.07% (0.03%, 0.14%) for young people aged 13 to 17 years.
73% of participants who tested positive did not report any symptoms at the time of swabbing or in the previous 7 days. This is similar to the proportion testing positive without symptoms in May, at 69%.
The prevalence was highest amongst those who reported classic COVID-19 symptoms (high temperature, new continuous cough, loss of smell or taste) at 0.29% (0.14%, 0.56%). This was significantly higher than for those reporting other symptoms at 0.03% (0.01%, 0.08%) or no symptoms at 0.02% (0.02%, 0.04%).
Conclusion
During the period 24 July to 11 August 2020, SARS-CoV-2 virus was circulating with relatively low prevalence but that prevalence was increasing through the period of testing.
Subsequent rounds of REACT-1 will allow accurate assessment of trends in prevalence and transmission.
Background
Read the press notice accompanying these findings
Read the pre-print version of this report