“We have two points of evidence; one is the evidence from King’s College London that shows that approximately one in 20 people with coronavirus is likely to have long-term symptoms, but the other evidence implies that in adults under 50, the proportion is more like one in 10. There seems to be some correlation that implies that it is more of a problem among younger people but the understanding of long Covid is still in its early stages and an awful lot more research is needed.”
Matt Hancock, 22 October 2020
The Health Secretary, Matt Hancock, told the House of Commons on Thursday that younger people were more likely to develop so-called “long Covid” after an initial infection with Covid-19. He also said that “there appears to be no correlation between the seriousness of someone’s initial illness and how long they can have these debilitating consequences.”
The longer-term effects of Covid are still poorly understood, but the evidence mentioned by Mr Hancock does not support his claim—indeed it suggests the opposite. According to the King’s College study, younger people and those with milder symptoms were less likely to be affected by long Covid.
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What do we know about “long Covid”?
At the time of writing, we know very little about who suffers from prolonged symptoms after a Covid infection. Nor is it clear why it happens, how often it happens, or how long it lasts.
The National Institute for Health Research (NIHR) has collected people’s experiences, and suggests that “long Covid” may not be one condition, but a mixture of different things.
On 21 October, a team of researchers, including some at King’s College London, published their analysis (not yet peer-reviewed) of data from the Covid Symptom Study app. This is based on 4,182 confirmed cases of Covid among people who consistently reported their symptoms in the weeks afterwards.
The King’s analysis is subject to several limitations—such as people over 70 being under-represented among the app users—but it provides some evidence on a subject where little is available, so far.
This data suggested that around one in 20 (4.5%, or 189 users) stayed ill for eight weeks. So Mr Hancock was right to say that one in 20 people would have long-term symptoms after a Covid infection—if you define “long-term” as more than eight weeks.
However, he was wrong to compare this to the one-in-10 figure for people under 50, because this describes those who suffered from symptoms that lasted more than four weeks—rather than eight.
As the research paper explains, the proportion of people experiencing “LC28” (meaning symptoms lasting more than 28 days) rose from 9.9% among 18-49 year olds to 21.9% among those aged 70 or more.
In other words, symptoms lasting more than four weeks were about twice as common among the over-70s as among the under-50s. A chart in the paper shows that the rate was also higher among people in their 50s and 60s. This is the opposite of what Mr Hancock suggested.
A spokesperson for Department of Health and Social Care (DHSC) told Full Fact that the study from King’s College “shows one in 20 people with COVID-19 are likely to have symptoms for 8 weeks or more. The study suggests long COVID affects around 10% of 18-49 year olds who become unwell with COVID-19.”
This statement simply repeats the mistake that Mr Hancock made, because it fails to explain that “long Covid” is being defined with a shorter period in the second sentence.
Do people with severe Covid have longer symptoms?
Based on the evidence from the app, Mr Hancock was also wrong to say that there was “no correlation” between the severity of the initial illness and the length of the symptoms afterwards.
The research paper says people with long Covid were “more likely to have required hospital assessment in the acute period.” Overall, 13.9% of the confirmed cases in the study had visited hospital. However, among those reporting symptoms for at least four weeks this rose to 31.5%, and among those reporting symptoms for at least eight weeks it was 43.9%.
The app data also suggested that “Individuals reporting more than 5 symptoms in the first week (the median number reported) were significantly more likely to go on to experience LC28 [symptoms lasting at least four weeks].”
In short, more severe cases of Covid seemed more likely to result in long Covid afterwards.
Is there any other evidence?
Mr Hancock told Parliament that “other evidence” supported his claim that young people were more likely to be affected by long Covid. But when we asked DHSC about this, it told us that the figures he quoted came from the same King’s study.
A DHSC spokesperson also directed us to a page of guidance from Public Health England (PHE), which says: “Around 10% of mild coronavirus (COVID-19) cases who were not admitted to hospital have reported symptoms lasting more than 4 weeks.”
This does not support Mr Hancock’s claims, however, and we cannot find any other evidence on the page that does.