They are known as the long-haulers.
A small, but growing and significant, percentage of Covid-19 patients, many of whom initially experienced a mild initial illness, who are suffering lasting effects.
Symptoms of 'long Covid' include, but are not limited to, breathlessness, cough, fatigue, brain fog and palpitations.
According to the Covid Symptom study, which was conducted in the UK, 10 per cent of people who contract the virus are still ill more than three weeks later.
And 5 per cent report symptoms lasting for months.
The tell-tale signs of lingering illness
The UK study identified six clusters of symptoms for the virus, some of which were associated with longer term symptoms.
"If you've got a persistent cough, hoarse voice, headache, diarrhoea, skipping meals, and shortness of breath in the first week, you are two to three times more likely to get longer term symptoms," said Tim Spector, professor of genetic epidemiology, King's College London, who led the study, in a recent webinar on the topic organised by the British Medical Journal.
According to Mr Spector, long Covid is twice as common in women than in men, and the average age of someone suffering from it was about four years older than people who had what might be termed as “short Covid”.
“We do seem to be getting different symptom clusters in different ages, so it could be that there is a different type in younger people compared with the over 65s.
"As we get more data we should be able to break it into these groups and work out what is going on … which could be very interesting and help us to get early interventions for those at-risk groups.”
Super-fit triathlete left struggling for breath
Long Covid sufferers in the UAE include Melina Timson-Katchis, a triathlete who used to train for hours each day before events.
Yet since having the coronavirus, she now struggles to exercise at all.
The 41-year-old from Cyprus is still suffering from bouts of dizziness, fatigue and chronic headaches, four months after getting the all-clear.
She has been diagnosed with post-viral syndrome.
“My symptoms were mild when the disease was first diagnosed," said Ms Timson-Katchis, a mother-of-three.
“I had a high fever and was more tired than normal but nothing major. Now, months on, the symptoms are slowing creeping up on me.
“I’ve never really been someone who suffers from headaches but now I get them regularly.
“They absolutely knock the wind out of me to the point where I am in bed for days sometimes.”
Although she did not suffer from chest symptoms at the time, she now experiences difficulty breathing and pain whenever she exercises.
She is now on an inhaler and is undergoing tests to see whether she has asthma.
Ms Timson-Katchis said the past few months had been life changing.
“I have undergone several tests, from a brain MRI to a cardiac angiogram, and while they have all come back okay it frustrating because I just don’t know what is wrong with me,” she said.
“I just started back training last month but it’s a fraction of what I am used to.
“I used to go out training on my bike as well as swimming and running, but now I have to use a stationary bike at home because my balance is completely off.”
Young professional left with 'smoker's lungs'
Eman Jamal, 35, contracted the virus in late April.
Her symptoms were classed as mild at the time, with a cough and difficulty breathing.
But almost five months on, the Palestinian-American communications professional is still suffering from bouts of chest pain and shortness of breath.
At first, every day was bad.
Now she is beginning to get some respite in between flares. In two of the past three weeks she felt good.
“Then suddenly the pain came back and the difficulty breathing returned for two full days. I was like oh my goodness, I thought this was over,” she said.
It lasted two days before subsiding again.
She has seen several doctors, who have diagnosed her separately with chronic obstructive pulmonary disease – a progressive condition typically associated with smokers – and asthma.
“The scarring in my lungs is gone. However, they do think it’s an airway problem. They say it could be asthma or chronic pulmonary lung disease (COPD).”
She sent her case files to a doctor in the US, who agrees it could be an airway problem. But it is not likely to be COPD.
“He said you are young. You’re not a smoker. You don’t have the profile for someone to have COPD," she said.
"He said he thinks it’s just something post-viral which could last from six months to a year.
“I’m hoping the time between the flare-ups or the down time, or whatever you want to call it, just keeps getting longer until it just goes away.
Frontline nurse knows what her patients go through
Seema Mary Rajan, 39, who works as a nurse at Al Zahra Hospital, Sharjah, said she has also experienced a number of health issues since testing positive in May.
“I still have a little heaviness in my chest and my breathing is also heavy as well as experiencing loose bowel movements,” she said.
“I also have been feeling pain in my joints, which is being investigated.
“I never had any issues with any of these before I had Covid-19.”
Despite the toll the virus took on her body, Ms Rajan is adamant she has been able to lead a normal life since being told she could return to work after testing negative in June.
Last month, the Indian mum-of-one told The National that her recovery had given hope to patients she was treating for the same condition.
“It was terrifying at first, I was so scared,” said Ms Rajan.
“But when I recovered and went back to work I saw the impact my recovery had on the patients.
“It helped them to stay positive.”
Bodybuilder trying to fight back after virus
Ahmad Zahalqa, a site engineer in Dubai, caught the virus in mid- April.
He came out of it by May 5, but is still suffering lingering shortness of breath, particularly during exercise.
His symptoms were intense during the initial infection, including extreme fatigue, insomnia, and shortness of breath, especially while sleeping.
“During the first week I could not even speak,” said the 28-year-old Palestinian-Jordanian.
“I did the test on Saturday, and on Sunday I started having horrible headaches - as if a belt was wrapped around my head and someone was pulling it.”
By Monday, he had lost his sense of smell.
“I asked some friends and they said those were coronavirus symptoms so I figured I must have it.
“However, I was not scared for one bit. It is essential to beat the virus psychologically, otherwise if you are scared of it, it will beat you and destroy you.”
He self-treated himself with Vitamin C, black flax seeds and “lots of onion and garlic”.
“I immediately started feeling that my internal system was recovering,” he said.
Within 14 days he tested negative. But to this day he still suffers shortness of breath, particularly during a work out.
“Until now when I train or make any sort of physical effort, I feel I am out of breath.”
Veteran doctor determined to shake off exhaustion
Symptoms of long Covid are wide ranging, and do not always include breathing problems.
For some, enduring fatigue is the main problem.
Others only experience pain, such as Dr Waguih Elsissi, a consultant orthopaedic surgeon and medical director of Ajman Specialty Hospital, who contracted Covid-19 while on duty in April.
“I suffer pain in my muscles. It's not constant pain though, it comes and goes but not on a daily basis, there is no time for it to happen,” he said.
Tiredness and exhaustion sets in quicker now than it used to before the infection, said Dr Elsissi, 80, from Egypt.
“Apart from that, I suffer from no other symptoms that are related to Covid-19.”