The Deputy Medical Director at the Beacon Hospital in Dublin said there is a lot about long Covid that is not known and a large amount of research in different areas will need to be undertaken to understand how this process occurs.
The HSE says fatigue, breathlessness, and cough, joint and muscle pain, chest pain, and palpitations are among the most commonly reported symptoms.
Professor Seamus Linnane, a founder of a special Long Covid clinic in Beacon Hospital, said there are a large amount of people suffering from the syndrome, and as it is a new health problem that the healthcare system has not faced before, there is clearly a large amount of unmet need.
He told RTÉ's Morning Ireland that patients are reporting a myriad of symptoms.
"This sort of characteristic notion of having booms and busts, having to pay for activities tomorrow that you do today and the inexplicability of the situation that people find themselves in frequently, never having had any sort of significant or major illnesses before, suddenly find themselves debilitated with their lives completely changed by what seems like an initial mild illness in somebody who was previously healthy but are now completely changed".
Prof Linnane said there is a lot that is not fully understood about long Covid.
"I think it's only as we see people and start to understand what it is that they're going through. I think there's quite a large amount of research in lots of different areas as people struggle to understand what's happening, and at the same time provide care within that sort of lack of understanding, or lack of full realisation, of how this process occurs".
He said there is quite a large number of people suffering from long Covid, which is obviously a new scenario and a new situation that the healthcare system has not faced before.
"So clearly, there's a large amount of unmet need, there's a large amount of people struggling and suffering and looking to try and find some kind of resolution for their symptoms. And clearly, we need to provide that", he said.
Lucy Adams, BBC Scotland's Social Affairs Correspondent, caught the Coronavirus in the spring of last year and has been suffering a range of debilitating symptoms ever since.
Tonight, she will feature in a BBC Panorama documentary called 'Long Covid: Will I Ever Get Better?’, which follows patients like her who are desperate to know when they will be well again.
She said she started recording a video diary when she first got Covid-19, thinking it would be a few weeks of illness.
Ms Adams said Covid is really taking its toll on her family and relationships.
She explained that the first seven days were not too bad and just felt like a kind of flu. But after a week it felt like it got significantly worse, she had a fever of 103F (39.4C), extreme pain in her lower back and kidneys, and really bad breathlessness, as well as the other symptoms that you would get with a flu.
Ms Adams described how at the time the NHS in England was so busy dealing with the coronavirus that she was advised not to go to hospital unless her "lips are blue".
She said it was a really difficult time because it was the first wave, people did not know very much about the illness and the UK was not carrying out community testing to confirm that she had Covid-19.
She said she assumed that within two weeks she would be better and would be back at work.
But that that just did not happen.
Now months later she says she is much improved but still has quite a lot of symptoms. She says she has not gone back to how she was before she got Covid but she feels she can do a lot more than she could 12 months ago.
She no longer immediately gets a fever, or immediately gets a migraine, after being active but she does have joint pain and fatigue.
Ms Adams said the issue also is that many of these symptoms are completely invisible to the human eye, and no one else can really see it, but her family sees how she crashes afterwards and still struggles with basic tasks.
Imperial College London has said its early research findings suggest a diagnostic test for patients with long Covid could be available within the next year.
The scientists also told BBC Panorama that pilot data had identified autoantibodies common to people with long-term symptoms but more detailed research now needs to be done.
Professor Danny Altmann of Imperial College London leads the research team. He said: "I’m famously optimistic, so I’d hope that within six months we’d have a simple blood test that you could get from your GP and that I think could have quite a big impact for people who don’t feel they’ve managed to convince their GP or accessed specialist care because instead of being my word against yours, it has a diagnostic test".
