REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in October 2020
Published 12 November 2020
Applies to England
© Crown copyright 2020
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Methodology
A representative cross-section of volunteers tested themselves with swabs from 16 October to 2 November 2020, inclusive. Swabs were analysed using polymerase chain reaction (PCR).
Results
Over the 18 days of the completed round of testing, out of 160,175 swab results, 1,732 were positive. The overall weighted national prevalence of infection in the community was 1.3% or 130 people per 10,000 infected, up from 60 people per 10,000 in the last report.
The weighted prevalence estimate is more than double that of 0.60% (95% CI, 0.55%, 0.71%) obtained in round 5 (18 September to 5 October 2020). The increase in prevalence represents a national doubling time of 24 (22, 27) days with a corresponding R estimate between rounds 5 and 6 of 1.19 (95% CI, 1.17,1.21).
However, following the rapid growth reported in the round 6 interim results covering the period 16 to 25 October, there is little evidence of growth during the second half of round 6 from 26 October to 2 November.
The estimated R for the first half of round 6 was 1.56 (95% CI, 1.27, 1.89) and for the second half it was estimated to be 0.85 (95% CI, 0.73, 0.99).
The possibility of systematic differences in the participant characteristics between the two halves of round 6 in comparison with the first and second halves of rounds 4 and 5 was investigated. While we did find differences in characteristics within rounds, patterns were similar across rounds 4, 5 and 6.
At regional level, based on analysis of rounds 5 and 6 (18 September to 2 November) together, R is increasing. However, consistent with the national trend, the rapid growth in the South during the first half of round 6 is no longer apparent in the more recent data.
The highest prevalence reported in the first half of round 6 was in Yorkshire and The Humber. Since then, there has been a substantial decline in prevalence in that region.
Nationally, prevalence increased across all age groups between rounds 5 and 6. However, there is a suggestion of decline in weighted prevalence in participants aged 5 to 12 years and to a lesser degree in those aged 25 to 44 years in the most recent round 6 data.
Conclusion
During the period 16 October to 2 November 2020, SARS-CoV-2 virus was circulating with significantly higher prevalence than between 18 September to 5 October and infections had increased substantially with 130 in 10,000 infected.
Subsequent rounds of REACT-1 will allow further accurate assessment of trends in prevalence and transmission.
Background
Read the pre-print version of this report