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expert reaction to latest ONS data on prevalence of ongoing symptoms following COVID-19 infection in the UK: 7 October 2021

The Office for National Statistics (ONS) have released the latest estimates of the prevalence people with self-reported “long COVID” using data from the UK COVID-19 Infection Survey.


Prof Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said:

“The latest monthly ONS release on self-reported “long Covid”, based on their Covid-19 Infection Survey (CIS), covers the four weeks up to 5 September. The CIS is a survey of a large representative sample of people living in private households across the UK. As always, bulletins in this series are based on survey respondents’ answers to the question, “Would you describe yourself as having ‘long COVID’, that is, you are still experiencing symptoms more than 4 weeks after you first had COVID-19, that are not explained by something else?”. This fits in with the current NICE definitions1 of ‘Ongoing symptomatic COVID-19’ (symptoms persisting 4 to 12 weeks after the start of the illness) and ‘Post-COVID-19 syndrome’ (symptoms persisting more than 12 weeks and not explained by something else). As always, the new ONS bulletin gives estimated numbers, and estimated percentages of the population, both for everyone who would report long-lasting symptoms and also for various groups of the population defined by their characteristics (age, sex, type of job, where they live, and more). It also gives results for various different durations of the symptoms.

“As in previous releases, the ONS results provide a depressing story in many respects. For this most recent four weeks, an estimated 1.1 million people in the country reported symptoms going on over four weeks – that’s about 1 in every 60 of the UK community population aged 2 and over. About 1 in 75 of that population, over 800,000 people, reported symptoms lasting 12 weeks or more, and about 400,000, that’s about 1 in 160, reported symptoms lasting a year or more.

“The rates of reporting ongoing symptoms do vary quite a lot between different groups – for example, about 1 in every 45 people aged between 35 and 69 reported symptoms going on for at least four weeks, but the rate was lower for people aged 70+ (about 1 in 90) and in younger people. For instance the rate for ages 12 to 16 was estimated at about 1 in 110.

“On one hand, it’s reassuring that the chance of having long Covid seems to be lower than average in this secondary school age group – but on the other hand, 1 in 110 of 11-16 year olds is about 35,000 children, and that’s not just a handful. Infection rates in that age group are currently very high, so I’d expect the rate of ongoing symptoms in that group to continue to increase. (In last month’s ONS bulletin, the estimate for that age group was 1 in 150, or about 25,000 children.)

“In some cases, while the ongoing symptoms might be unpleasant, they weren’t reported as having large effects on people’s day-to-day activity. But about one in five who reported symptoms, going on more than four weeks, said that the symptoms were affecting their ability to carry out day-to-day activities a lot, compared to the situation before they had Covid-19. That’s well over 200,000 people across the UK. Of those who reported symptoms lasting over a year, an estimated 90,000 would say that their daily activities are impacted a lot. That’s serious.

“A new feature of this month’s bulletin is an analysis of how the various figures have changed since the previous bulletin, which covered reported ongoing symptoms in the four weeks ending 1 August. (It was always possible to calculate the changes by looking at the ONS data files for successive months, but it’s very good to have some of the work done and the results interpreted by ONS.) So roughly that’s a comparison between the numbers reporting ongoing infections during August and during July this year. ONS report that the estimated numbers with ongoing symptoms increased compared to the previous month, with the total figure going up from 970,000 to about 1.1 million. ONS say that that is the largest monthly increase since they started these regular publication in April this year.

“The change in these estimates is the net effect of two things. First, some people will newly be included in the count because they wouldn’t have reported long-term symptoms in July, but would do so in August. That would generally be because, in July, there symptoms had not yet gone on for four or more weeks, but in August, their symptoms had gone on for four or more weeks. So, roughly speaking, the numbers would increase because of people being infected during July and having symptoms that went on for four or more weeks into August. But, as well as these increases, the number can be reduced because people, who had ongoing symptoms during July, no longer have those symptoms during August. People who have long Covid can recover from it.

“ONS consider (and I agree) that the large increase in the latest figures compared to the month before is because infection rates were relatively high in July this year, compared to a lot of the previous months when this particular analysis was being done. That’s borne out by the fact that much the biggest increase was in numbers who were originally infected less than eight weeks previously. People who were first infected July this year couldn’t have been infected for eight or more weeks by the end of August, because eight weeks hadn’t elapsed since their infection. Indeed many of those first infected in June also couldn’t have been picked up as having a longer-lasting infection than eight weeks in August, unless they were surveyed towards the end of the August four-week period.

“ONS also report on the changes, between the previous bulletin and this, in numbers reporting ongoing symptoms in various subgroups of the population. Increases were particularly high in the 17-24 age group, and in people working in hospitality, and in arts, entertainment or recreation. Neither of these surprises me at all, since those are all areas where infection rates were relatively high during July, because younger people mostly hadn’t been vaccinated yet, and because the removal of lockdown measures had increased the infection risk for people in hospitality and entertainment. Overall, across employment groups prevalence of long-lasting symptoms (4 weeks and over) remains highest in people working in health care (1 person in 33) and social care (1 in 36). But hospitality is now third in this unpleasant league, with 1 in 38 having ongoing symptoms (the same rate as for people working in the civil service or local government). In the previous bulletin, hospitality was tenth in that league, with about 1 person in 60 reporting ongoing symptoms.

“What this is all telling me is that there’s an ongoing major problem with long Covid. As recently as July, people’s infections were leading to symptoms that went on for four weeks or more, and in many cases considerably more. I see no reason to believe that this has stopped, and since overall infection rates are now at levels not much different from those in July, we’re likely to see increased numbers reporting long Covid in next month’s ONS bulletin and probably for more bulletins going into the future.”




All our previous output on this subject can be seen at this weblink:



Declared interests

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  I am also a member of the Public Data Advisory Group, which provides expert advice to the Cabinet Office on aspects of public understanding of data during the pandemic.  My quote above is in my capacity as an independent professional statistician.”

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