WOULD it surprise you to be told that the mortality from all causes in 2020 was lower than it ever had been before?
Actually, it’s cheating to say that. The mortality rate in August 2020 was 836, lower than it ever has been. For comparison, the August death rate in the exceptionally good year of 2019 was 867. Why on Earth was the death rate in August 2020, the year of Covid, so low?
Was there Covid in the country? Yes.
Were there compulsory masks? No!
Were there lockdowns? No!
Was there social distancing? No!
And yet the death rate in August last year was lower than it ever had been.
There are two reasons it was so low. The first was that the month was August. Whether it is dry conditions, ultraviolet from the sun, or population vitamin D levels, respiratory disease epidemics don’t happen in August, even without masks, lockdowns or social distancing.
With so much Rambo-esque talk abounding (‘We will beat this together’), we need to remind ourselves that the way the world works is much more significant than the power of governments.
The second reason for the low death rate last August was the high death rate in April 2020. A death rate above average is inevitably followed by a lower rate because some who died in April would have died in August anyway. Covid hastened their deaths, but some of us are going to die soon and that is inevitable.
This is the second natural influence more powerful and predictable than government action – the unavoidable way that high death rates are followed by lower ones, and vice-versa.
This brings us back to the question I left last time as to what we should have expected in 2020, in view of the previous pattern of death rates. Only by knowing what 2020 would most likely have been without Covid are we in a position to assess what the impact of Covid has been.
The pattern of respiratory diseases is that they come in autumn and have gone by the following autumn. Though they generally peak in January, sometimes it is earlier and sometimes later.
These early or late starts of the disease season swing the calendar year figures considerably. December to January figures are also muddied by late reporting during the holiday period.
A much more consistent picture of mortality is produced by August to July figures, carving up the year during the times that respiratory diseases are at their lowest. This is how August to July mortality has varied since 2001.
From this you can see that the mortality from August 2019 to July 2020 was entirely normal. Actually it was below average – 12th out of the 19 years. In the respiratory infection year in which the Covid first wave arrived, deaths were below average for the preceding 19 years.
Of course I haven’t taken into account the high death rates in December 2020 to February 2021, but these are part of the respiratory infection year that we are in at the moment. Only by August 2021 will we see the figures for this year. For reference, here are the actual mortality figures for the August to July years.
The natural oscillations caused by low mortality leading to high mortality are still evident in the previous Age Standardised Mortality chart. But we can deal with these by averaging over a two-year period, like this:
The two-year rolling average removes most of the oscillating component from the mortality figures, showing the steady trend of the overall death rate. Mortality between August 2018 and July 2020 was nearly as low as it ever has been – 1032.7 compared with 1032.1 for 2017-2019 – in other words, just like the previous year. Here are the figures.
None of this is saying that Covid is a trivial and ignorable disease. Those of us who have had it know it to be very unpleasant.
It can be nastier for a small proportion of those who get it, even a few who are fit and well. For those, the body’s response to it leads to life-threatening conditions, as a result of which one or two fit individuals in a typical city have died. Covid is a new and unpleasant disease and we do not yet know how best to treat it.
But the figures show that the overall statistical effect of Covid is so small that, had there not been exceptional reactions to it among a few in good health, we would simply not have noticed it.
Covid is one cause of the normal cyclical mortality of respiratory diseases, the rate of which is determined primarily by time of year and the numbers of vulnerable people left in the population after previous years’ epidemics.
The deaths during the Covid first wave have been in line with previous years and figures such as 85,000 excess deaths in 2020 due to Covid are not at all supported by government-published data.
The death rates have been high from December 2020 until now. What do we expect to be the consequence of that?
If the primary determinants of mortality are time of year and previous deaths, we expect the mortality to the end of July 2021 to be in line with the above figures.
That means we expect the mortality in the coming months to do exactly what happened in 2020, and to drop below normal so that, over the whole ‘respiratory year’ the mortality will not be significantly different from other years and the two-year mortality to be even closer.
Undoubtedly some will say that, without masks, distancing and lockdowns, mortality would have been much higher. Some will say that the measures have flattened the curve and helped the NHS. Those are different questions and people have different views.
If by then we are allowed, I look forward to lunch invitations in early August where we can talk through the figures. Bearing in mind that current dietary recommendations for vitamin D correspond to 400g of tuna or 20 eggs per day, I’ll provide the vitamin D pills.
Statistical note: Figures are from the Office of National Statistics. Age standardised mortality for the August-July years is found by raw averaging monthly published figures. I have neither corrected for numbers of days in the month, nor changing demographic figures, neither of which will affect the conclusions.
