REACT-1 study of coronavirus transmission: June 2021 interim results
Published 8 July 2021
Applies to England
© Crown copyright 2021
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Methodology
A representative cross-section of volunteers in England, ages 5 and over, tested themselves with swabs from 24 June to 5 July inclusive. Swabs were analysed using polymerase chain reaction (PCR) for the presence of SARs-CoV-2.
Results
Over the 12 days of testing which form these interim findings from round 13 of REACT-1, 237 of 47,729 swab results were positive giving a weighted national prevalence of 0.59% (0.51%, 0.68%), or 59 people per 10,000 infected. This is an increase of 0.44% when compared with round 12 (20 May to 7 June) where weighted prevalence was 0.15% (0.12%, 0.18%). The period between the end of round 12 and the beginning of round 13 showed evidence of exponential growth with an estimated doubling time of 15 days (13, 17), and a corresponding R number during this period of 1.32 (1.27, 1.37).
During this interim round 13 report that covers 24 June to 5 July, accelerated growth was observed in comparison to between round estimates. There was an estimated national doubling time of 6 days (4, 12), and an R number of 1.87 (1.40, 2.45).
These findings show that the number of infections increased in all regions of England, when compared with findings in round 12. The largest increase was in London where prevalence increased more than eightfold from 0.13% (0.08%, 0.20%) in round 12 to 1.08% (0.79%, 1.47%) in round 13 findings.
There was a substantial increase in prevalence in all age groups under the age of 75 years, and especially at younger ages.
The highest weighted prevalence of swab positivity was found in those aged 13 to 17 years at 1.33% (0.97%, 1.82%) and those aged 18 to 24 years at 1.40% (0.89%, 2.18%). Prevalence in older school-aged children (13 to 17 years) increased eightfold from 0.16% (0.08%, 0.31%) in round 12 (20 May to 7 June).
Conclusion
During the period 24 June to 5 July, the number of SARS-CoV-2 infections continued to rise exponentially when compared with the last round of REACT-1: round 12 (20 May to 7 June), with 59 in 10,000 infected (1 in 170 people infected). The highest rates were observed regionally in London and in those aged 18 to 24 nationally.
A final report of round 13 of REACT-1 which includes additional subsequent days of testing will be published in due course.