Tens of thousands of people with so-called “long Covid” have had symptoms of illness for more than three months, reports suggest.
Professor Tim Spector, who is leading the Covid Symptom Study app, said that 60,000 people have been ill for more than three months.
While some people have a mild form of illness, others have been seriously affected.
People affected with long-term symptoms have described how they have been previously fit and healthy and now they are confined to a wheelchair.
Breathlessness and fatigue have been reported by long-term sufferers and some have described how doing shopping or climbing stairs can leave them bed-ridden for days.
Prof Spector, professor of genetic epidemiology at King’s College London, told BBC Radio 4’s File On 4 that data from the app shows that around 300,000 people have reported symptoms lasting for more than a month – so called “long Covid”.
Up to 60,000 people reported having symptoms for more than three months.
Jeanne Jarvis-Gibson, 27, used to lift weights and ran almost every day before her Covid symptoms began in March – she has yet to run since but lately has tried yoga and walking.
She had no pre-existing conditions but at the peak of her illness required antibiotics for a chest infection, suffering breathing difficulties which have improved but still remain.
“There were days I was scared to go to sleep because I was scared of not breathing,” the University of Liverpool postgraduate student, originally from Maryland in the US, told PA.
“I am very tired of being tired… I want to be able to explore and do fun activities without my body hindering and slowing me down.
“This virus does not care who you are in this world, not your age, your wealth, or status.
“I am a 27-year-old fit woman, and it hit me very hard… and these long term symptoms are still scary for me.”
But Professor Spector said he is “frustrated” that data from the app is not being more widely used.
“There’s a big danger these (people) might end up being forgotten,” he told File On 4.
Health Secretary Matt Hancock told the Health Select Committee on Tuesday that the long-term effects of coronavirus were not “very strongly correlated” with the severity of the infection.
Mr Hancock said that with the current rise in Covid cases being linked to younger people it was “really relevant” that even people with mild symptom could end up with a “terrible illness” lasting many months.
He added: “This is not just about people who were hospitalised, in fact, and this is really relevant for now because the latest rise in the last few days has been largely among young people.
“But it doesn’t matter how serious your infection was first time initially, the impact of long Covid can be really debilitating for a long period of time, no matter if your initial illness wasn’t all that severe.”
Meanwhile, the programme asked commissioning groups and health boards across the UK whether they had set up post-Covid clinics for patients who were not admitted to hospital with the virus.
Of the 86 who responded, 10 said they were already running such facilities. A further 16 said they were planning or redesigning services.
Many patients will be seen by their GP, or existing services.
NHS England’s new Your Covid Recovery website offers personalised support for all patients recovering from Covid.
Lynne Turner Stokes, professor of rehabilitation medicine at King’s College London, told File On 4 the website had some “good resources” but that “we have to do much more”.
A spokeswoman for the NHS in England said: “While experts globally continue work to understand more about the short and long-term impact of this new disease, NHS teams are rapidly expanding aftercare and support to all patients who need it, including new and strengthened rehab centres and community services providing tailored treatment in every part of the country, such as the first of its kind Seacole centre, and a new online health advice and support platform, which patients said they wanted to help them recover at home.”
It comes as new guidance published on the Government website sets out some of the long-term health effects for some people who have had Covid-19.
The guidance states that around 10% of mild coronavirus cases who were not admitted to hospital have reported symptoms lasting more than 4 weeks.
And a number of people admitted to hospital reported continuing symptoms for eight or more weeks following discharge.
Persistent health problems following acute disease have included: respiratory symptoms and conditions such as chronic cough, shortness of breath; lung problems including inflammation and scarring; heart issues including chest tightness, heart failure and scarring; protracted loss or change of smell and taste; mental health problems including depression, anxiety and cognitive difficulties; inflammatory disorders such as muscle pain; gastrointestinal problems; continuing headaches; fatigue, weakness and sleeplessness; liver and kidney dysfunction; clotting disorders and thrombosis; problems with the lymph nodes and skin rashes.
Meanwhile, researchers in Glasgow have launched a study examining the long-term health impacts of Covid-19.
The study will measure prevalence and risk factors of long-term health and psychosocial consequences of the disease.