MRC Biostatistics UnitWe have published a new report on our real-time tracking of COVID-19 .
We have highlighted the key updates and provided interpretation of what these updates mean. We have also explained our recent model and report changes.
Updated findings
- Our current estimate of the daily number of new infections occurring each day across England is 49,700 (35,500—70,900, 95% credible interval).
- The daily number of new infections is particularly high in the Midlands, the North East and Yorkshire (14,900, and 12,100 infections per day, respectively). Note that a substantial proportion of these daily infections will be asymptomatic.
- We predict that the number of deaths occurring each day is likely to be between 255 and 388 on the 28th of November.
- We estimate Rt to be around 1 in all regions. The probability of Rt exceeding 1 is above 80% only in the Midlands and South East.
- The growth rate for England is estimated at 0.0 (-0.02–0.01, 95% credible interval) per day. This means that nationally the number of infections has stopped growing with initial evidence of possible decrease in the North West and North East and Yorkshire.
- 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 20% and 19% respectively. The South West continues to have the lowest attack rate (4%).
- 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 Rt values are around 1 in all regions. The plots of the Rt over time show clear downward trends. These lower values of Rt are likely to be the result of various social distancing interventions, detected through the Google mobility data, and the school closure during the half-term period.
The number of new infections is decreasing in the North West, plateauing in the East of England and London and still increasing, though at a much lower rate, in the other regions. Furthermore, it is anticipated that we are approaching a peak in the number of deaths occurring each day. Despite this, the number of publicly announced deaths may continue to increase for a while, as this number represents deaths reported the preceding 24 hours rather than occurred within the previous 24 hours (for more information see nowcasting COVID-19 deaths).
The lock-down introduced on the 5th of November will have induced changes in contact patterns, which cannot be quantified with any certainty at this point, but have the potential to induce a continued decrease in the Rt values and the number of new infections. Further changes will be reflected in the weekly iterations of our model.
Quote from lead researcher – Professor Daniela De Angelis, Programme Leader and Deputy Director
“There is evidence that the pandemic is temporarily slowing down: the Rt values are estimated to be around 1 in all regions and the total number of new daily infections is now around 50,000, a revision downwards from last week’s estimate. These trends and the predicted peak in the number of deaths occurring daily are likely to be the result of the social restrictions and the temporary decrease in activity over the half-term period, both prior to the recent lockdown. Further changes in the Rt values and the number of new infections will depend on the impact of the lockdown on people’s behaviour. We continue to monitor the situation closely.”
Model and report changes
- 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.
- 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.
- 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.
- The modelling now accounts for a different susceptibility to infection in the under-15s, using information from literature (Viner et al, 2020) suggesting that children less likely to acquire infection when in contact with an infectious individual.
Link to full report: https://www.mrc-bsu.cam.ac.uk/nowcasting-and-forecasting-19th-november-2020/
Contact for media enquiries
Alison Quenault