Why the coronavirus death toll is misleading – and how we’ll get the true figures

This year, numbers have taken on a more prominent role in all our lives. From the two-metre social distancing guidance to the R0 rate of infection, coronavirus statistics permeate our daily lives. Among the most worrying numbers are those relating to cases and deaths.

When the COVID-19 pandemic abates, will we be able to measure the full extent of its damage? Will we know how many people it really killed? These may seem like peculiar questions given the daily focus on specific case numbers. But these numbers don’t tell the whole story, and likely leave out many deaths. To get a more complete picture, we need to look at the total number of deaths from any cause, and compare these numbers with the expected figures for the period, based on historical averages and forecasts.

For example, in the week ending 3 April, the UK recorded 3,475 COVID-19 deaths. That same week saw 16,387 deaths from all causes registered in England and Wales (other parts of the UK have separate statistical offices). That was the highest number of deaths in a single week since January 2000 – 6,082 more deaths than you would expect on average for that time of year.

In the circumstances, it would be natural to assume that at least some of those ‘excess deaths’ could be attributed to the pandemic. (Some may have been caused by other factors that have could have changed - obesity levels, for example.) But according to current practices, none of these excess deaths are included in COVID-19 mortality figures.

Between January and April 2020, the data for England and Wales includes around 27,000 excess deaths, according to analysis carried out by The Financial Times. That’s a jump of 52%. Other countries’ all-cause death tolls have also seen huge increases over the same period: Italy (90%), Spain (72%), Belgium (60%). Generally, cities have been the worst affected.

Italy has just revised its coronavirus-related death toll. One of the hardest-hit countries, it was the first in Europe to impose a nationwide lockdown. By 6 May, Italy had confirmed 213,000 infections and 29,315 deaths.

But according to ISTAT, Italy’s official statistics body, the excess death figures paint an even bleaker picture. In March, there was a 49% increase in deaths throughout the country, compared with the five-year average. Broken down regionally, that 49% starts to look even more concerning. In northern Italy, there was a 95% increase in deaths, while in the region of Lombardy, which includes the city of Milan, the number of deaths was up by 186%.

Delays and differences

According to the European Mortality Monitoring Project (EuroMOMO), there has been “a marked increase in excess all-cause mortality overall for the participating European countries, coinciding with the current COVID-19 pandemic”. But across the world, there is no uniform approach taken to collecting the figures.

One only has to look at the different approaches taken toward testing (widely used in South Korea, for example, but far less so in nearby Japan) to see how difficult is to make direct comparisons. The higher the number of tests, the greater the likelihood of identifying infections. So one country’s total number of cases will be affected by how many tests it conducts.

Even with confirmed deaths from COVID-19, there is frequently a lag between a death being registered and the cause of death being factored into national statistics. The Republic of Ireland, for example, has what EuroMOMO calls “very significant delays in death registrations during March and April 2020”.

Problems with accurate counting in turn lead to challenges with reliable forecasting. The US is currently moving towards a relaxation of lockdown restrictions. Previous mathematical models indicated the number of COVID-19 fatalities in the country would fall within the range of 59,300 and 114,200. But a revised forecast from the University of Washington’s Institute for Health Metrics and Evaluation (IHME) offers a far gloomier outlook.

According to IHME, by early August the lowest anticipated death toll is 95,092, rising to 242,890 at the upper end of the forecast. Their mid-range predicted number of 134,475 is thought to represent the most likely outcome. As of 6 May, the US had recorded 71,078 coronavirus deaths.

Despite the delays and differences, every death that was really caused by coronavirus will be counted within overall, all-cause death statistics. Identifying the gap between the expected averages and the deaths actually recorded will help reveal a truer death toll. But reaching these figures will take time and further analysis.