How many are still ill with COVID-19?

Given that the NHS doesn’t have good records on these patients, how do you find out the scale of the problem? One way is using the UK’s COVID symptom tracker app, which has got millions of willing participants logging the symptoms they’re experiencing every day. Phil Sansom spoke to Tim Spector from King’s College London, who leads the team looking through the data…

Tim - We noticed this after about the first month of collecting symptoms, and we found that there was a group of people who just kept logging. The average duration of symptoms was between 10 and 12 days, but around 10% of them had symptoms that lasted for over a month; perhaps one in twenty still have symptoms three months on. One in twenty people, when you think of perhaps 3 million people infected in the UK, is a lot of people with debilitating symptoms.

Phil - That's a huge proportion. What kind of symptoms were these people getting?

Tim - Well, we ask in the app about 19 symptoms, and the ones that seem to be coming up strongest were fatigue; a really severe fatigue that initially meant it really could hardly get out of bed. And that would often cycle as well, so it would improve and then get worse. Muscle aches was another common thing that has persisted, and shortness of breath. The other one which was rather strange, which occurred in about a fifth of these people, was loss of smell; and this seems to be lasting months in some people, which doesn't sound very important until you start thinking about how that really affects your ability to appreciate food and drink, and can make you very depressed if you lose it. But people were presenting with a whole range of different symptoms on top of that. We actually had three people that after three months, we're still having intermittent fevers.

Phil - Wow.

Tim - It was just really strange. And we had about 8% of people that had rashes that would appear on their fingers and toes. This weirdness of symptoms and variety is now starting to be understood, because it looks like there's different antibody responses in all these different subgroups. But I think as time goes on, we'll see this not as necessarily one disease, but as perhaps six or 10 sub-diseases or sub-responses to this identical virus.