Updated findings

1. Our current estimate of the daily number of new infections occurring each day across England is 55,600 (38,400–81,600, 95% credible interval).
2. The daily number of new infections is particularly high in the North West and the North East and Yorkshire (17,600 and 14,800 infections per day, respectively). Note that a substantial proportion of these daily infections will be asymptomatic.
3. We predict that the number of deaths each day is likely to be between 237 and 422 on the 5th of November.
4. We estimate R_t to be above 1 in most regions with almost 100% probability, apart from London for which the probability of R_t exceeding 1 is 67%.
5. The estimated growth rate for England is estimated at 0.04 (0.03–0.05, 95% credible interval) per day. This means that the number of infections is growing by 4% each day. This translates into a doubling in the number of new infections approximately every 17 days.
6. London, followed by the North West, continues to have the highest attack rate, that is the proportion of the population who have ever been infected, at 21% and 18% respectively. The South West continues to have the lowest attack rate (4%).
7. Note that the deaths data used are only weakly informative on Rt over the last two weeks and are still occurring in relatively small numbers in some regions. Therefore, the estimate for current incidence, Rt and the forecast of daily numbers of deaths remain very uncertain.

Interpretation

The R_t values almost certainly remain above 1 in all regions except London, where the probability that R_t is above 1 is 67%. This indicates that the number of new infections occurring each day will continue to rise, unless further interventions or behavioural changes are introduced.

Despite this, the plots of R_t over time show decreases over the last few weeks in most regions, while showing a plateauing in the South East, South West and East of England. This, together with the R_t remaining greater than 1, means that the number of new infections continues to rise, but at a slower speed.

These lower values of R_t might be the result of the various social distancing interventions, but it is unclear what the impact of any single intervention is from this analysis; and the continued rise in the number of new infections will probably continue unless further interventions or behavioural changes are introduced.

Quote from lead researcher, Professor Daniela De Angelis (Deputy Director and Programme Leader at the MRC Biostatistics Unit, University of Cambridge)

“The estimated trends in R values and growth rates show signs that the epidemic is growing at a slower pace in most regions. However, the rising number of infections and the R values remaining above 1 clearly indicate continued transmission, leading to the prediction of a steep rise in the number of CoVID-19 deaths. Curtailing this transmission will require sustained social distancing interventions.”

Model and report changes

1. The definition of deaths has been adapted to include all deaths that occur in individuals who have had lab-confirmed infection within 60 days from the date of their most recent positive test. This definition reflects more realistically the burden of COVID-19.
2. Using observations of improved survival in hospitalised COVID-19 patients, we have allowed the probability of dying following infection with SARS-CoV2 (the infection-fatality rate, IFR) to gradually change over the course of June 2020, with a decrease being estimated.
3. The model uses seroprevalence data on the presence of COVID-19 antibodies in blood samples taken by NHSBT to estimate the levels of cumulative infection within the population over time. As, from early June, the NHSBT has been giving a constantly declining prevalence of antibodies, and these data have been curtailed at this point.

Link to full report: https://www.mrc-bsu.cam.ac.uk/nowcasting-and-forecasting-29th-october-2020/