REACT1 round 7 interim update (13-24 Nov 2020):

We estimate that R has dropped < 1 (0.88 (0.86, 0.91)) during the second national lockdown.

Full preprint (not yet peer reviewed): imperial.ac.uk/medicine/resea…

More great work from @DrCWalters @eales96 @HaoweiWang7 @SRileyIDD

1/n Results
- We found 821 positives from 105,123 swabs
- Unweighted prevalence of 0.78% (95% CI, 0.73%, 0.84%)
- Weighted prevalence of 0.96% (0.87%, 1.05%)
- The weighted prevalence estimate was ~30% lower than that of 1.32% (1.20%, 1.45%) obtained in the second half of round 6

REACT-1 study update: Prevalence of swab positivity had increased to over 1 in 200 in England as of 26 Sep 2020. Weighted prev = 0.55% (0.47%, 0.64%). This implies 411,000 (351,000, 478,000) people are virus-positive.

Full results on medrxiv: medrxiv.org/content/10.110… (1/n) Main results:
- 363 positives from 84,610 samples
- Weighted prev = 0.55% (0.47%, 0.64%)
- This continues upwards trend in prevalence seen since mid-Aug
- Highest observed prev since beginning of study in May 2020 & more than a four-fold increase in weighted prev observed in r4

Our latest results from the REACT-1 study show that prevalence of #COVID19 is increasing in England. Main results are highlighted below.
The full (not yet peer reviewed) pre-print is available here: tinyurl.com/y3jw765x (1/n)

@SRileyIDD @DrCWalters @eales96 @HaoweiWang7 The epidemic declined between rounds 1 and 2, and 2 and 3, but was increasing between rounds 3 and 4: doubling time 17 (13, 23) days and R=1.3 (1.2, 1.4)

From the most recent round 4 data (22nd August and 7th September): doubling time 7.7 (5.5, 12.7) days and R=1.7 (1.4, 2.0)

Prevalence of #COVID19 in England is trending downward. Our new preprint on REACT 1 study found continued decline in prevalence and a shift in pattern of infection by age and occupation at end of initial lockdown in England. (1/n)
@SRileyIDD @DrCWalters
tinyurl.com/y6xzjppj - Over both rounds combined, we estimate an
- average halving time of 38 (28, 58) days
- reproduction number (R) of 0.89.

- The proportion of asymptomatic swab-positive participants at the time of sampling increased from 69% (round 1) to 81% (round 2).

Our new preprint shows there was a rapid and synchronised reduction in UK mobility just before and after the announcement of lockdown on 23 March. It's now live on @WellcomeOpenRes
wellcomeopenresearch.org/articles/5-170…
@SRileyIDD @DrCWalters (1/6) We used data from @Facebook and a UK mobile phone provider and found synchronised mobility patterns all across the UK (regardless of data source or geographic region). The largest reduction in mobility occurred around the time of the announcement of lockdown. (2/6)

When can the lockdown end? The results in our new preprint in @WellcomeOpenRes illustrate how the eventual decorrelation between transmission and movement is likely a key feature of successful #COVID19 exit strategies. wellcomeopenresearch.org/articles/5-81/…
@SRileyIDD @DrCWalters @MRC_Outbreak Using daily reported cases from mainland China and Hong Kong SAR, we estimated transmissibility over time and compared it to daily within-city movement, as a proxy for economic activity.