The author of a study examining the impact of COVID-19 says that up to one in ten people who contract the virus could suffer long-term effects.
The study found that young and previously healthy people with ongoing symptoms of coronavirus were showing signs of damage to several organs four months after initially testing positive for the virus.
The Coverscan study assessed the long-term impact of the virus on organ health among 500 “low-risk” individuals, with early data from 200 participants showing that almost 70% have impairments in one or more organs.
"Long COVID” is believed to affect more than 60,000 people in the UK.
Dr Rajarshi Banerjee, CEO of Perspectum and author of the report, told The Pat Kenny Show that 5-10% of people who had symptomatic COVID may experience long-term effects.
However, Dr Banerjee said "we don't really know" the exact number of people who will be affected by "long COVID".
He said: "The estimates that have come out of University College London are that 5-10% of all people who have symptomatic COVID may get long COVID.
"The biggest problem with long COVID is that is causes prolonged periods off work with fatigue, breathlessness, chest pain, weakness and a symptom known as brain fog where just concentrating becomes difficult.
"None of these symptoms are life-threatening, I want to assure people that long COVID isn't going to be as traumatic to deal with.
"However, it's of significant economic and personal burden, even for simple activities in daily life like childcare."
Dr Banerjee said that when they undertook the study, they wanted to emerge with "a good news study".
He explained: "We wanted to say if you get COVID and you don't get hospitalised, you come through at the other end and in three months you'll all be back to normal, that would have been a very positive story for the global community.
"Unfortunately we can't say that, we can't say if you get past COVID, you'll be fine because we've effectively discovered this long COVID phenomenon which you can also get with other illnesses.
"It appears that this current coronavirus is one of these viruses that has an acute phase and a long phase."
He added that the study found that the "bulk of the damage" to organs from long COVID is to the heart.
He said: "The kind of impairment we're talking about does not require hospitalisation, but it means that you're more tired.
"The heart is often affected, the kidneys are often affected, the pancreas, the liver and the spleen."
It comes as US company Moderna said yesterday that its coronavirus vaccine is 94% effective with no significant safety concerns.
It is the second major international trial to report positive results after Pfizer said its candidate was more than 90% effective last week.
Dr Banerjee said he was "literally over the moon" at the news.
He said he had spoken to people behind the Moderna vaccine and they had been working "non-stop" since the virus emerged.
He said: "It's important to understand the scale of the trials that Pfizer and Moderna have done.
"There are the most efficacious vaccines that have ever been made for any indication.
"The vaccine seems to protect you from the virus and it also seems to protect you from severe consequences of the virus.
"We don't know yet if it protects you from long COVID, that's to be seen, but it's a huge step forward."