MRC Biostatistics UnitToday we have published a new report on our real-time tracking of the COVID-19 pandemic. This information is helping the government to track the COVID-19 pandemic in real time.
We have highlighted the latest findings and provided interpretation of what these findings mean. We have also explained our recent model and report changes.
Updated findings
- The current estimate of the daily number of new infections occurring each day across England is 4,730 (3,390–6,670, 95% credible interval).
- The daily infection rate is estimated to be the highest in the West Midlands (WM), East Midlands (EM), Yorkshire and the Humber (YH) and the North East (NE) with 692, 433, 474 and 245 new daily infections, corresponding to 12, 9, 9 and 9 per 100,000 population, respectively. Note these regional estimates are highly uncertain and that a substantial proportion of these daily infections will be asymptomatic.
- We predict that the number of deaths occurring daily is likely to remain low with a forecast for the period around the 14th May suggesting that there will be between 21 and 59 deaths per day.
- The probability of Rt exceeding 1 is 73%, 68% and 64% in the South West (SW)WM, London (GL) and WM, respectively; 55% and 54% in the in the East of England (EE) and South East (SE); around 30% in Yorkshire and Humber (YH), EM and NE; and approximately 20% in NW. WM is the only region with a higher estimate for both incidence and Rt.
- The growth rate for England is estimated to be positive at 0.01 (-0.01–0.03, 95% credible interval) per day. This means that, nationally, the number of infections is increasing, although there is heterogeneity across regions, with negative growth in some of them.
- London, followed by the WM and the NE, have the highest attack rates, that is the proportions of the regional populations who have ever been infected, with 33%, 21% and 20% respectively. The SW continues to have the lowest attack rate at 10%. These constitute a big downward revision from our previous published report, particularly so for the NW.
- Note that the deaths data used are only very weakly informative on Rt over the last two weeks and are thankfully becoming increasingly sparse. Therefore, the estimate for current incidence, Rt and the forecast of daily numbers of deaths are likely to be subject to some revision.
Interpretation
The plots of the estimated Rt in the most recent weeks are heavily influenced by the effects that the Easter holidays and the gradual relaxation of pandemic mitigation measures have on mobility. Currently, as restrictions are being relaxed we anticipate a very gradually increasing Rt over the coming weeks.. The Rt for five regions have central estimates just above 1 (EE, GL, SE, SW, WM), although these estimates are uncertain. At current levels of incidence, these values of Rt are not a particular concern, though they do require careful monitoring as the national lock-down is gradually relaxed.
The incidence of deaths has continued to fall more sharply than predicted by the model, with a transition to plateau still anticipated. The number of new infections, as the Rt values indicate, is also flat in almost all regions.
The plot of the infection fatality rate (IFR) presents age-specific probabilities of death given infection. It shows an increasing mortality risk from September onwards in all ages until the immunisation programme begins to have an impact in late January. From the end of January we estimate a decreasing IFR in all adult age groups, but most steeply in the older ages. This drop measures the benefits of immunisation against death over and above the benefits against infection. Specifically, there is an estimated fall to a still-high 15%% in the over-75s and 0.5% overall. The overall impact of the immunisation programme can be seen more clearly in the ‘All Ages’ plot, where the precipitous decline in IFR since late January is a product of this efficacy against death but also of the increasing proportion of infections in young people as older age groups are immunised and become protected against infection. The impact of the second immunisation doses becoming widespread will begin to affect this quantity over the coming weeks.
Since the last published report, the estimates of cumulative infection have been revised substantially downwards. This is due to the inclusion of the prevalence data, which have the effect of reducing the number of infections. Nowhere is this more true than in the North West, where estimates of attack rate have fallen from 31% to 18%. London remains the region with the largest levels of cumulative infection to date.
Other indicators (e.g. hospital bed prevalence, reported new cases) continue to suggest a declining epidemic. Prevalence of infection, as estimated by the ONS Community Infections Survey is now around 0.10% in England with some regional heterogeneity. It is hoped that this trend continues as further pandemic measures are progressively relaxed along the government’s roadmap to opening society. We will continue to monitor the situation closely.
Additional comment from lead researcher – Prof Daniela De Angelis
“The pandemic continues to shrink in England, undoubtedly as a consequence of the combined effects of pandemic mitigation measures and the ongoing immunisation programme. Signs of the impact of immunisation on the risk of both infection and mortality are becoming apparent: infections are falling in the oldest age-groups and a declining fraction of infections are leading to death. However, the relaxation of measures at each step of the roadmap and the possible incursion of new variants into the country retain the potential to disrupt the current downward trend and will require careful monitoring.”