During the coronavirus pandemic, the Continuous Mortality Investigation (CMI) is publishing frequent UK mortality analysis through its mortality monitor. The latest update covers week 53 of 2020 (26 December 2020 to 1 January 2021) based on provisional England & Wales deaths data published by the Office for National Statistics (ONS) on 12 January 2021.
The CMI notes that ONS has reported 53 weeks of registered deaths data this year, compared to 52 weeks in most years.
The key points of this update are:
- Death rates for 2020 have been 13.4% higher than in 2019.
- There have been around 72,900 more deaths in the UK from the start of the pandemic to 1 January 2021 than if mortality rates were similar to those experienced in the previous year. Of these, 12,100 have occurred in the second wave.
- The number of deaths with COVID-19 mentioned on the death certificate was 3,144 in week 53, compared to 2,912 in week 52. However, the week 52 and week 53 figures are relatively low as Register Offices were closed on one bank holiday in week 52 and two in week 53.
- Considering weeks 52 and 53 together, there were 7% more deaths registered in England & Wales than if death rates had been the same as for week 52 of 2019 and week 1 of 2020 (52 weeks earlier). We caution that while combining weeks 52 and 53 reduces the impact of the timing of bank holidays, the figure of +7% for excess deaths is still lower than it would have been in the absence of bank holidays.
- This week’s monitor contains additional analysis comparing measures of excess deaths that use different benchmarks. We show that the widely-used comparison to the average number of deaths in recent years exaggerates excess deaths during the pandemic by nearly 15,000 deaths compared to the CMI method, which allows for a growing and ageing population.
Cobus Daneel, Chair of the CMI Mortality Projections Committee said:
“The coronavirus pandemic has led to death rates in 2020 being 13% higher than in 2019. This is by far the highest annual increase in recent years, and the largest annual increase since 1929.
“While recent excess deaths figures are hard to interpret due to bank holidays, all indications are that we continue to see material excess deaths.”
All mortality monitor weekly updates are publicly available on the mortality monitor page.
The publication of ONS data broadly follows ISO week numbers. Most years have 52 ISO weeks, but because a 52 week year has 364 days, less than a calendar year, some years, including 2020, have “leap weeks” under the ISO system.
The CMI’s “Excess” deaths are the difference between actual deaths in 2020, and those that we would have expected if death rates had been the same as a year earlier. Others have calculated excess deaths by comparing actual deaths in 2020 to average deaths in 2015-19. However, this measure does not recognise that we would have expected deaths to increase during that period, even if death rates did not, due to a growing and ageing population.
The ONS data released today relates to registered deaths. As Boxing Day and New Year’s Day fell in week 53 of 2020, there were fewer deaths registered than would otherwise have been the case. As our comparator week, week 1 of 2020, 52 weeks earlier, had only one bank holiday rather than two, its registered deaths were not reduced as much, so the excess deaths for week 53 (comparing week 53 of 2020 to week 1 of 2020) are lower than if the pattern of bank holidays had been consistent.
The CMI’s analysis of ONS data shows that there have been over 12,000 excess deaths in the second wave. However, the corresponding figure for registered deaths with COVID-19 mentioned on the death certificate is over 32,000. Death rates from other causes have been significantly lower than is typical at this time of year.
For the purposes of the mortality monitor, the CMI treats the first wave of the pandemic as being week 10 onwards (i.e. from 29 February 2020) and the second wave as being week 38 onwards (i.e. from 12 September 2020).
The cumulative week 53 figure for excess deaths is lower than the corresponding figure for week 52. This is because of the timing of bank holidays, as noted above.
The CMI intends to publish its next mortality monitor for week 1 of 2021 on Tuesday 19 January 2021.