We 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. The lead researchers have also given their headline comment.

Updated findings

1. The estimated number of new daily infections on the 17th December across England is 57,600 (50,100–66,400, 95% credible interval). The daily infection rate is estimated to be 103 per 100k population per day nationally. The highest rate is now in London (GL) with 154 infections per 100K population followed by the East of England (EE) at 140. These rates correspond to 13,700 and 8,680 daily infections, respectively. There is then a drop to the South East (SE) (116), South West (SW)(109) and West Midlands (WM) (98). In the remaining regions rates are around 60 per 100K population. Note that a substantial proportion of these infections will be asymptomatic.
2. The daily number of deaths has been declining, but it is now slowing to a plateau such that we forecast between 103 and 172 deaths per day by the 7th of January.
3. This week we believe the national Rt to be very close to 1, with values estimated to be over 1 in the EE and GL, resulting in 92% and 77% probabilities of a growing epidemic, respectively. This probability is reasonably high in both the North West (NW) and WM (46% and 35% respectively). For everywhere else, the chance of Rt being above 1 is around 25% or less.
4. The growth rate for England is 0.00 (-0.01– 0.01) per day. This means that, nationally, the number of infections is flat, corresponding to an Rt of around 1.0, slightly higher than the most recent estimate.
5. Our estimates for the attack rate, that is the proportion of the regional populations who have ever been infected, have the North East (NE) at 51% and GL at 50%. WM, East Midlands (EM) and NW are all also above the national average with 46%, 43% and 43% respectively. The SE and SW continue to have the lowest attack rates at 34% and 33%. Note that the deaths data used are only very weakly informative on Rt over the last two weeks. Therefore, the estimate for current incidence, Rt and the forecast of daily numbers of deaths are likely to be subject to significant revision.

Interpretation

The number of reported new positive cases (by date of specimen) has been increasing exponentially for the last two weeks, resulting from the rapid growth of the B.1.1.529 variant, known as Omicron, particularly in GL. In contrast to the cases, admissions to hospitals have just started to rise after a period of decline, with, again, the increase particularly pronounced in GL. The prevalence of infection, as estimated by the ONS Coronavirus Infection Survey, is around 1.70% showing no real change from previous weeks. It is, as yet, too early for the omicron variant to have any impact on the numbers of deaths. As there is no clear signal from omicron in the data that we use (ONS prevalence, deaths, serological swabbing), it would appear that what is being estimated here is a summary for pandemic infection with the delta variant. This would, for example, explain a number of infections that is markedly lower than the daily reported number of SARS-CoV-2 cases.

Bearing this in mind, our estimates show a pandemic with Rt values estimated mainly very close to 1. This is reflected in infection incidence which has remained generally constant, apart from in GL and the EE where the number of infections has started to increase.

Plots of the IFR over time show that we are currently estimating a decreasing IFR in all age groups with the most steep fall in the younger age groups. Following this drop, the overall IFR is 0.24% (0.22%–0.25%), highest in the over-75s at 3.1% (2.9%–3.4%), similar to that estimated in our most recent publication.

Comment from lead researchers, Prof Daniela De Angelis & Dr Paul Birrell

“Daily reported numbers of SARS-CoV-2 cases have seen substantial growth over the last two weeks, driven by the emergence of the B.1.1.529 “Omicron” variant. This surge in cases is yet to translate into the data we use to produce our epidemic summaries, and consequently our estimates need to be interpreted cautiously, as they most likely represent trends in infections with the Delta variant. We still estimate a stable national epidemic, with an overall infection rate now at around 100 per 100,000 population. Regardless of Omicron, prevalence of COVID19 remains high, and the number of deaths is anticipated to no longer be decreasing over the coming three weeks.”

We will continue to monitor the situation closely over the holiday period, to report any emergent signal from Omicron, to understand the extent to which the surge in cases is due to increased transmission rather than case ascertainment, and whether prevalence will increase from its already-high levels.

Read full report: Report on Nowcasting and Forecasting – 22nd December 2021 – MRC Biostatistics Unit (cam.ac.uk)