Coronavirus live: England’s health secretary recovers from Covid; Italy records further 5,000 cases

According to the BBC, on 15 October, the prime minister allegedly sent a WhatsApp message: “I must say I have been rocked by some of the data on Covid fatalities. The median age is 82 – 81 for men, 85 for women. That is above life expectancy. So get Covid and live longer.” Presumably, this was a joke, but why is the reasoning so wrong?

First, more technically, the message confuses two types of averages. As children learn at school, the median means that if you lined up the women according to the age they had died of Covid-19, the woman in the middle would be 85.

But life expectancy is a mean-average – you work out how long, say, 100,000 newborns are likely to live assuming that current mortality rates continue, add them up and divide by 100,000.

Using data from the UK for 2017-19, life expectancy at birth is 79 for men and 83 for women, but the median age at death is slightly higher: 81 for men and 85 for women, the same as that quoted for Covid-19.