Independent report

REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in November 2020

Published 30 November 2020

Applies to England


A representative cross-section of volunteers tested themselves with swabs from 13 November to 24 November, inclusive. Swabs were analysed using polymerase chain reaction (PCR).


These results represent an interim report (7a) for round 7 of REACT-1. Over the 12 days of the completed round of testing, out of 105,123 swab results, 821 were positive. The overall weighted national prevalence of infection in the community was 0.96% or 96 people per 10,000 infected, down from 130 people per 10,000 infected shown in the last report.

The decrease in prevalence between rounds 6b (26 October to 2 November 2020) and 7a represents a national halving time of 37 (30, 47) days with a corresponding R estimate of 0.88 (0.86, 0.91). Using data only from round 7a, the estimated R number is 0.71 (0.54, 0.90). After the fall and rise previously reported for 6b (26 October to 2 November 2020), the smoothed estimate of prevalence suggests an increase into the start of the second lockdown followed by a decrease.

Between rounds 6b and 7a, there was a decline of prevalence across all regions which was most evident in the North West and North East, where prevalence was reduced by over 50%. In contrast there was little change in prevalence between rounds 6b and 7a in East and West Midlands and London. The highest prevalence is now in the West Midlands at 1.55%.

At the regional level, R numbers between rounds 6b and 7a ranged between 0.76 (0.71, 0.82) for North West to 0.95 (0.86, 1.04) for London. R numbers between round 6 (16 October to 2 November) and round 7a were similar, but slightly higher.

Differences in local prevalence between rounds 6b and 7a (averaged at the level of lower-tier local authority (LTLA)), reveal sub-regional patterns mainly of decline especially in North West, North East and Yorkshire and The Humber, with local areas of growth still seen in East and West Midlands.

In the most recent round 7a data compared with round 6b (26 October to 2 November), there was an increase in weighted prevalence in participants aged 5 to 12 years and 13 to 17 years. At all other ages there was a decline in prevalence between rounds 6b and 7a.

In further analyses adjusting for other variable, people of Asian ethnicity had 1.72 (1.27, 2.35) increased odds of testing positive compared with white people, 1.09 (0.80, 1.49): this demonstrates a contrast to the results from 6b. Those living in the most deprived neighbourhoods had higher odds of being swab positive than those living in less deprived neighbourhoods. Healthcare workers and care home workers had 1.69 (1.29, 2.22) increased odds of testing positive compared with other non-key workers.


During the period 13 November to 24 November, SARS-CoV-2 virus was circulating with significantly lower prevalence than between 26 October to 2 November and infections had decreased substantially with 96 in 10,000 infected.

Subsequent rounds of REACT-1 will allow further accurate assessment of trends in prevalence and transmission.


Read the pre-print version of this report

Read the press notice accompanying these findings

Read previous REACT-1 monthly reports