WE know that more people die in the winter than in summer. The difference between the higher winter mortality and the death rate in summer is known as excess winter deaths (EWD) and one can chart historic EWD as follows, using data from the Office for National Statistics (ONS):
The EWD figures from winter 1950-1951 through to last winter show that these often see-saw from one year to the next, although there are exceptions where, for example, one year that showed an increase is followed by another year that shows a further more modest increase.
This could be caused by a severe winter having a great impact on mortality, which will have removed many vulnerable people from the population. The remaining population would consequently be relatively more robust, resulting in a lower EWD figure for the following year.
The five-year moving average for EWD in the graph shows that actual year-to-year EWD deviates quite widely. And although the average is rising towards the end of the period, actual EWD for last winter, 2018-2019, was the fourth lowest – and one might quite reasonably expect it to be followed by an increase for the following winter. The graph that follows helps examine if this is the case.
The pattern of EWD is apparent in the week-by-week figures for England and Wales produced by the ONS:
This chart shows the weekly returns of all deaths registered in England and Wales from the start of 2018 to March 27, 2020, which is the latest available figure. There are clear peaks around the start of the year followed by gradual reductions into the summer, with a slow build-up thereafter.
The dotted red line shows the average number of deaths in any given week over the previous five years. So there is a reasonable degree of consistency in the pattern of deaths, with the actual number being sometimes above and sometimes below the average, as one would expect.
Concentrating on just the current winter season, deaths up to year-end 2019 tended to be slightly above average and slightly below average thereafter. The net actual position for this 23-week period is almost in balance, with total deaths this winter less than 0.1 per cent above average.
Week 13 is the latest week for which we have data from the ONS and this shows deaths increasing and diverging from the average. The chart above shows the actual 2020 numbers in black and the five-year average as a dotted red line.
The thin dotted lines give the records from 2015 to 2019 and demonstrate that there can be considerable divergence from the average as winter advances into spring. Then as spring moves into summer, the volatility subsides and lower and more subdued numbers become typical.
In conclusion, an upswing in EWD for 2019-2020 was likely. But on present showing, any purely cyclical increase is unlikely to reach the 2017-2018 peak. Any increase in mortality due solely to Covid-19 has yet to be reflected in the data, but the possibility of such an increase as subsequent numbers are released should not be discounted.
The ONS figures used here show returns for all deaths and so it follows that deaths due wholly to Covid-19 infection are so far either too small to be detectable in the overall mortality rate, or that mortality from all other causes must have decreased in proportion to the number of new Covid-19 deaths.
Covid-19 deaths are thus lost in the statistics, because the population is currently less susceptible to other causes of death. In other words, the population is healthier than usual, but Covid-19 deaths are masking that improvement. This is unlikely to be the case.
An impending peak in Covid-19 infection is not something that these numbers can help us with. What is demonstrable, however, is that the charts above reflect a period before the economy was shut down with a population that was associating quite freely and where it is claimed that Covid-19 was propagating. Yet from January to March 27, 2020, the number of deaths from all causes was nearly 4,000 below the average.
Making Covid-19 a notifiable disease will serve only to skew the data. The way to monitor the situation independently is to focus on the numbers for all deaths in order to have a basis of comparison with historic numbers and to track the progress of Covid-19 in the days ahead.