Video report by ITV News Health Editor Emily Morgan
Words by ITV News Multimedia Producer Suzanne Elliott
The effects of Long Covid, as it has become known (although this is not a medical term), are far reaching - with a vast array of symptoms encompassing both physical and neurological - that drag into weeks and often months.
Seven in ten Covid-19 patients are still suffering after five months of being discharged from hospital, new research shows.
The UK-wide study, led by the National Institute for Health Research and the University of Leicester, also revealed one in five of the participant population reached the threshold for a new disability.
Listen to the latest episode of our Coronavirus podcast, including a special on long Covid and what's being done to help sufferers...
Scientists analysed 1,077 patients who were discharged from hospital between March and November 2020 after contracting Covid-19. The PHOSP-COVID study is the largest of its kind in the world.
An earlier study by King's College London found an estimated 10% of people with the virus take at least three weeks to recover, with 250,000 people in the UK alone thought to experience symptoms for 30 days or more.
Many of those experiencing long tail coronavirus were fit, active people whose lives have been completely turned upside down by the ongoing symptoms.
What do we know about Long Covid, how is it affecting people and is there help for those who need it?
What are the symptoms?
Researchers from the National Institute for Health Research and the University of Leicester found each participant had an average of nine persistent symptoms including muscle pain, fatigue, physical slowing down, impaired sleep quality, joint pain or swelling, limb weakness, breathlessness, pain, short-term memory loss, and slowed thinking.
Other symptoms that have been linked to Long Covid include 'brain fog', a lack of concentration, mental health problems and even hair loss among some 'long haulers'.
Dr Rachael Evans, an associate professor at the University of Leicester and respiratory consultant at Leicester’s Hospitals, said: "Our results show a large burden of symptoms, mental and physical health problems and evidence of organ damage five months after discharge with Covid-19.
"It is also clear that those who required mechanical ventilation and were admitted to intensive care take longer to recover."
She added: "However, much of the wide variety of persistent problems was not explained by the severity of the acute illness - the latter largely driven by acute lung injury - indicating other, possibly more systemic, underlying mechanisms."
Who is more likely to get Long Covid?
White women aged 40 to 60, who have at least two long-term health conditions, have the most severe prolonged reactions, according to Professor Chris Brightling, a professor of respiratory medicine at the University of Leicester.
He said: "While the profile of patients being admitted to hospital with Covid-19 is disproportionately male and from an ethnic minority background, our study finds that those who have the most severe prolonged symptoms tend to be white women aged approximately 40 to 60 who have at least two long term health conditions, such as asthma or diabetes."
How are different age groups affected?
Dr Evans said the team, led by Chris Brightling, Professor of Respiratory Medicine, are "definitely seeing a good proportion of people" with ongoing symptoms such as fatigue, breathlessness and problems with concentration.
And while older ‘long-haulers’ are struggling with worsening memories post-virus, Dr Evans says young people are also suffering from what is often described as "brain fog".
"People feel very different to the way that they're able to think and process things compared to before (they had) Covid.”
They are also seeing a proportion of people that have higher levels of anxiety and depression.
What do we know?
One thing medical experts and scientists do know is there are a lot of unknowns about Long Covid.
Professor Chris Whitty, Chief Medical Officer and co-lead for the National Institute for Health Research, said: "We are in the foothills of our understanding of long term effects of Covid.
"This research provides useful information on the debilitating effects of Covid some people are living with months after being hospitalised.
"It is important that we work out what exactly the various elements of what is currently termed 'Long Covid' are so we can target actions to prevent and treat people suffering with long term effects."
A separate study found that in as many as half of patients, even those who were not hospitalised, Covid-19 had a damaging effect on the body's key organs.The study by COVERSCAN, a joint national research programme between the EU, Innovate UK, and Perspectum, began in April on 160 patients with a median age of 43.
Preliminary data found 50% of patients have evidence of either heart, liver or kidney damage.
Many patients who have had Covid, especially men, have subnormal heart pumping function.
Is there a link between the intensity of the acute stage and Long Covid?
Researchers are finding that, certainly at this stage, there isn't.
"One thing we are learning... is we're not seeing a direct correlation between the severity of the acute illness to then who's developing these long term symptoms," Dr Evans says.
"So it's not as clear cut.
"We're seeing people where they have recovered from the intensive care unit and made a full recovery and are back to work.
“And those where they've had a relatively minor disease, acutely, but then have really developed these symptoms that just don't seem to be going away and this is after months."
Is there any treatment?
As Dr Martin Marshall, chair of the Royal College of General Practitioners and a GP at a practice in Newham acknowledges, Long Covid is “going to be a real challenge” for the health service as well as patients.
One area medicine and science is looking at is a link between Long Covid and other post-viral illnesses like ME, but at the moment, as Dr Marshall says “we're not quite sure what works, because it hasn't been around for long enough”.
He says GPs are giving patients “pretty much common sense” advice and encouraging them to boost their immune systems through healthy eating and gentle exercise.
“It feels awful when you've got the symptoms, but most people improve,” he says.
“Use your common sense in terms of resting, not overdoing it, doing a bit of exercise, but not too much - graded exercise, if you like... gentle exercise that doesn't fatigue you, doesn't wear you out is important.
“Eat well, don't drink too much.
"So standard, healthy living stuff, really, which just helps boost your immune system because it's possible that post Covid it is some kind of immune reaction or some kind of abnormal immune reaction or deficient immune reaction to the Covid itself.
"We don't know for sure, but that's one of the hypotheses.”
Film director Gez Medinger tells ITV News in July 2020 about his experiences with Long Covid
How does Long Covid affect sufferers?
Sandra Moult from Queniborough in Leicestershire described the feelings of fatigue she still continues to endure after contracting Covid-19.
She told ITV News: "I'm still suffering from feeling really fatigued and tired, which is frustrating because I don't have the energy that I used to have.
"(I'm) still getting pains in my back, swollen legs and ankles, which I still don't know if that's related to Covid or not so I'm just waiting to see - I've also had to go on extra blood pressure tablets to overcome that."
Ms Moult continued: "And when I came out of hospital I had mouth ulcers, pains in the back of my ear and that was an ear infection."
"It's just all these little things that you didn't expect when you came out of hospital you start to get a bit better but there are things that make you think it's not going to go back downhill," she added.
Matt Bromley, 40, a teacher from Altrincham in Greater Manchester, spoke to ITV News in week 19 of what he describes as a "rollercoaster journey".
He fell ill with presumed Covid in late March when tests for the general public were not available. But all his symptoms pointed to coronavirus and later, on his first of three visits to A&E, doctors identified that his lungs were recovering from pneumonia.
His most acute stage was during the Easter weekend, when he was unable to get up and down the stairs due to shortage of breath, a continuous cough, chest pain and chills.
Easter Sunday was "hellish" and he felt so ill he wondered whether he would live to see his son Sebastian's second birthday the following week.
But while he did survive, there has been little respite from the disease that has left him bed and garden bound, unable to look after his two young children or resume his teaching job in September.
Matt was fit and healthy with no underlying health conditions, a "natural fidget" who swam weekly, competed at a national level in dinghy sailing events and who usually spent summers exploring Scandinavia with his wife Andrea and their four and two-year-old in their camper van.
But summer 2020 was very different.
"It's affected my life in every way and has been extremely taxing, especially with young children around the house and having been so fit and active until this started.
"After four and a half months of being unwell, it's impossible to know how long it will take me to recover," Mr Bromley said.
His current symptoms include a "horrible tightness" across his chest which he describes as feeling "like I'm being constricted around my heart by a snake".
He also has heart palpitations, headaches and dizziness.
"Talking is extremely difficult and when I do have a conversation for five minutes or so, I'll need to lie down afterwards for 45 minutes or so for it to recover," he says.
"I have also lost some dexterity in my left hand and am suffering from extreme fatigue (post viral fatigue).
"At the moment, I'm spending at least half a day in bed and the rest of it either lying down or, in better spells, sitting in a chair.
"Reading and screen time brings on an intense headache within 10 mins.
"I'm totally house and garden bound, as any physical exertion (like a five minute walk) flares up the symptoms and triggers a relapse.
"There have been a handful of encouraging days but being a novel virus, there is nobody who can say with any authority how long, or even, if I'll make a full recovery."
What help is out there now?
The NHS offers a Covid-19 rehab service for people who have been suffering with the long-term effects of the virus.
Your Covid Recovery Service initially launched online but it will become a face-to-face portal when safe to do so.
When should I see my GP?
Dr Marshall said: “If patients are concerned, then that's the time to go (and see your GP) and if somebody has had Covid like symptoms, they think they've had acute Covid, and they're still getting symptoms after three weeks, I think it's perfectly reasonable after three weeks to think that now is the time to go along and see the GP.
He says that while most patients simply have to sit out the disease, visiting your GP could just help ease a worried mind that could be causing greater anxiety.
“It depends a little bit on how good you are at tolerating symptoms and tolerating that uncertainty,” Dr Marshall says.
“But I think it's perfectly reasonable if the problems are going on and you're worried about it to go along, and the GP might just reassure you if he or she is quite confident that it does look like Long Covid and can't be anything else.
“Or they might want to run a few just basic tests, like basic blood tests, to exclude anaemia or a thyroid problem.
“In conventional Long Covid, all of the tests will come back as normal.”
But in the meantime, in a world facing a disease with so many unknowns, long haulers are braced for a long road to recovery.