Covid kills, but do we overestimate the risk?

Lockdown sceptics the world over continue to argue that the measures we are taking to deal with Covid-19 are far too heavy-handed, and that we are all massively overestimating the risk of the virus.

“It’s no worse than the flu!’ they cry. “All the people dying of Covid were going to die soon anyway!” they wail. “The only reason people are accepting these measures is that they have a false sense of how dangerous this virus is!” they shriek.

And they have some eye-popping stats to back up their points. Many of them — including proto-sceptic Toby Young and the Guido Fawkes blog — pointed to research published in July showing that the average Briton thought that 7 per cent of the population had already been killed by the virus (and 10 per cent for the average Scot). On Wednesday, Young posted a Daily Mail story on Twitter that said 5 million Britons had already had the virus. “Given that ~50,000 people have died from it, that means it has an IFR of <0.1%. That’s roughly the same as seasonal flu” tweeted the Toadmeister, in a now-deleted tweet.

As you might have already spotted, that is out by a factor of 10. And to be fair to him, Young did own up to his error in a subsequent tweet and pointed out he had been up until 6am that morning and was a little tired. But the idea that Covid “isn’t that much worse than the flu” is a common theme on both Young’s Lockdown Sceptics blog and in general Covid-sceptic commentary.

Recent research suggests that the IFR (infection fatality rate) is in fact between about 0.5 and 1 — that’s between five and ten times higher than for the flu. But as the Lockdown Sceptics blog has itself pointed out before, trying to work out Covid’s overall IFR is not a terribly fruitful exercise given how much the risk of death varies between different demographics.

As David Spiegelhalter, chair of the Winton Centre for Risk and Evidence Communication at Cambridge university and rock star statistician said to us in a recent chat:

It’s very difficult to estimate mortality risk - when you have something that varies at least by over 1000-fold depending on your age or risk factors, the average is pretty pointless.

The former stat, on Britons’ perception of Covid deaths, isn’t completely wrong, but it is misleading. Although it is technically correct, there are — as we all know from GCSE maths — three kinds of average. The one used here was the mean , which as Full Fact has pointed out , is not very appropriate in this context. If the median had been used instead, it would have shown that the average Brit actually thought that 1 per cent of the population had died.

Do the sceptics have a point?

But despite their selective use of stats, that’s not to say there is no truth to any of what the sceptics are saying. Even if Brits think 1 per cent of the population has died, they’re still out by a factor of 10. And yes, coronavirus’s IFR might be five to ten times higher than the flu’s, but the flu also affects the young far more than coronavirus seems to.

The flu hospitalises hundreds of young children and kills around a dozen kids under the age of 15 each year. So far the only children that have died in this country with Covid-19 already had “profound” underlying health conditions , according to a report in the British Medical Journal .

Meanwhile, polling carried out this month by Savanta ComRes also suggests the average Briton doesn’t realise the extent to which coronavirus mainly targets the old. This polling suggests the median Brit thinks the average age of death from Covid is 65. In fact, though, that number is currently 82.4. And that’s in a country where the average life expectancy is 81. (Though it must be remembered that by the time one reaches the age of 81, one’s average life expectancy is between 88 and 90, depending on if you’re male or female. It’s a bit complicated — we have tried to explain this before here and here , if you’re interested.)

So yes, it appears that the average Brit is overestimating the risk of death from Covid. Prof Spiegelhalter earlier this year worked out that the chance you have of dying from Covid if you catch it is roughly the same as your risk of dying over the coming 12 months anyway. Because the Covid death rate appears to have now fallen — due to a number of factors, including better hospital treatment and also possibly people getting a smaller viral load because of the various measures in place — Prof Spiegelhalter now reckons catching coronavirus gives you about six or nine months’ worth of risk of dying, rather than a whole year’s worth. (You can read a more thorough explanation of this here if this makes your head hurt.)

He recently tweeted these charts, showing the data from March and October, which shows an incredibly close correlation between Covid fatality risk and overall mortality risk (based on age only, so not including other comorbidities):

In other words, you really don’t want to catch it, but if you do, it “only” doubles the risk of dying that you would normally have in the coming six to nine months. Depending on how old or unwell you are, that might make the risk of death quite significant.

So does that therefore vindicate those who make the “they would have all died anyway” argument? No. Prof Spiegelhalter estimates that only 5 to 15 per cent of the deaths are people who would have died this year. He also points out that after a huge spike in excess deaths during the spring, there was no great deficit in deaths over the summer. If all that we saw during the first wave had simply been “harvesting”, to use a gruesome term — ie, a short-term increase in the mortality rate that then causes a subsequent drop in deaths because some of the most vulnerable people will have died during the earlier spike — we would have seen a big fall in the summer months, which we didn’t.

And of course there are other risks than death. One of the things that the sceptics don’t spend much time talking about is the long-term effects of catching the virus, about which we still know relatively little. Research suggests about 1 in 20 people is likely to suffer from so-called Long Covid. (It should also be pointed out that other viral infections, such as glandular fever, can also cause autoimmune diseases. )

Still, it’s clear that the way we as a society perceive risk from Covid is not always completely justified by the facts. It seems that some of us overestimate it while others of us do the opposite, depending on our approach to risk, personal liberty, and our general political persuasion.

This Alphavillain wrote a Notebook column for today’s paper (that this post/ramble is intended as complementary to) pointing out that the measures we currently have in place for tackling Covid-19 are also effective in tackling other respiratory pathogens, such as the flu, meaning that flu deaths are likely to be incredibly low this winter. Indeed they have already been in other parts of the world — check out this graphic from the WHO:

Although we think of the flu as highly contagious given how many of us catch it, it seems to be the case that we have never bothered trying to not spread it around in the past. It is in fact much less contagious than the novel coronavirus, and the measures we have in place to deal with the latter are effectively stamping out the former. Perhaps our tolerance of flu deaths, which we normally take for granted, will change. In that case, might that undermine our resilience in different yet unknown ways? That’s another risk that we know little about.

But it seems that our attitude to risk is not a constant. Despite the fact that globally, coronavirus deaths are back around their late-April peaks, we are no longer seem so shocked by the numbers of people dying. And despite the fact that hospitalisations in the UK are near their springtime peaks — though critical care bed occupancy was slightly below the normal range for winter as of Nov 8 — we are no longer clapping for the NHS every Thursday.

Bleak — or perhaps hopeful, depending on your side of the argument — as it might sound, we have started to get used to Covid. But we are getting used to something whose risks we still don’t quite understand.

Related links: Covid could change our tolerance of the flu - FT Why are we really in lockdown? - FT Alphaville Spiegelhalter says majority of Covid deaths would not have occurred in coming year - FT Alphaville Why the second wave of Covid-19 appears to be less lethal - FT COVID cases are spiking, but our attention isn’t - Axios The strange world of risk perception, and communicating risks - The BMJ Opinion