One in 20 people infected with mild Covid in the first wave of the pandemic were left with lingering symptoms up to three years later, research has suggested.
US scientists found respiratory and neurological issues were the common problems still reported by those struck down with the virus in 2020.
And the researchers, who tracked more than 135,000 Americans with Covid, also discovered a 34 per cent higher risk of problems with all organs among people hit hardest with Covid and hospitalised.
Experts today labelled the findings an ‘important new lesson’ and warned the virus ‘should not be trivialized’.
Dr Ziyad Al-Aly, a clinical epidemiologist at Washington University and senior author of the study said: ‘We aren’t sure why the virus’s effects linger for so long.
Latest ONS data on Covid infections shows more than 80 per cent of Brits suffer a runny nose when infected. A loss of taste or smell — one of the original tell-tale signs of the virus — accounts for just under a fifth of all symptoms logged
‘Possibly it has to do with viral persistence, chronic inflammation, immune dysfunction or all the above.
‘We tend to think of infections as mostly short-term illnesses with health effects that manifest around the time of infection.
‘Our data challenges this notion. I feel Covid continues to teach us — and this is an important new lesson — that a brief, seemingly innocuous or benign encounter with the virus can still lead to health problems years later.’
He added: ‘Addressing this knowledge gap is critical to enhance our understanding of long Covid and will help inform care for people suffering from long Covid.’
US Government data suggests up to 10 per cent of people infected with virus have experienced long Covid.
Often self-diagnosed, the term was coined for a number of symptoms following Covid infection, which can persist for months or even years after the initial infection.
Around 1.9million people in the UK are reported to suffer with it, with the term covering everything from fatigue and breathlessness to muscle and joint pain.
The researchers analyzed data from 114,000 veterans with mild Covid who did not require hospitalisation, over 20,000 patients hospitalised with the virus and 5.2million veterans who never received a Covid diagnosis.
All were enrolled in the study between March and December 2020.
Over a follow-up of three years, they found the risk of long Covid stood at 23 per cent one year after infection.
This fell to 16 per cent or roughly one in six after two years.
Concerningly, they also found that among those who weren’t hospitalised, Covid had contributed to 10 lost years of healthy life per 1,000 people, three years after infection.
By comparison, those who were hospitalised with Covid had lost 90 years of healthy life per 1,000 people.
In the US, heart disease and cancer cause around 50 years of lost healthy life, while strokes contribute to roughly 10 years, per 1,000 people.
Writing in the journal, Nature Medicine, the researchers, said: ‘Although preventing severe disease is important, strategies to reduce the risk of post-acute and long-term health loss in people with mild Covid are also needed.’
However, they also acknowledged the study mainly involved veterans who were ‘mostly older’, white and male and may not be reflective of other populations.
Participants also contracted the virus in 2020 — an era predating Covid vaccines — suggesting their infection may have been more severe.
Dr Al-Aly added: ‘Covid is a serious threat to the long-term health and well-being of people and it should not be trivialized.
‘Even three years out, you might have forgotten about Covid, but it hasn’t forgotten about you.
‘People might think they’re out of the woods, because they had the virus and did not experience health problems.
‘But three years after infection, the virus could still be wreaking havoc and causing disease or illness in the gut, lungs or brain.’
It comes as Covid cases continue to slowly increase across the UK, after infection rates dwindled over the spring.
Earlier this month, health chiefs issued an alert over a new variant, nicknamed FLiRT, they had begun monitoring.
It makes up around 30 per cent of new cases in the UK currently.
FLiRT also accounts for roughly a quarter of new cases in the US, surveillance data suggests.
Virologists are using the term FLiRT to describe a family of different variants — KP.2, KP.3, JN.1.7, JN.1.1, and KP.1.1.
They are all descendants of the JN.1 variant that has been dominant in the UK for the past few months. That itself was dubbed Juno.
Ministers have repeatedly said that they won’t resort to imposing lockdowns unless a doomsday variant.
A wall of immunity among the population — built up by repeated waves of infection and vaccine rollouts — has given officials confidence to consign pandemic-era measures to history.
Spikes in Covid cases can still cause mass illness across the country, sparking chaos in schools, the health service and public transport.
Officials also no longer track the prevalence of the virus in the same way they used to, as part of the Government’s ushering in of pre-Covid normalities.
It comes as Covid cases continue to slowly increase across the UK , after infection rates dwindled over the spring. Earlier this month, health chiefs issued an alert over a new variant, nicknamed FLiRT, they had begun monitoring. It makes up around 30 per cent of new cases in the UK currently
Often self-diagnosed, the term ‘long Covid’ was coined for a number of symptoms following Covid infection, which can persist for months or even years after the initial infection. Around 1.9 million people in the UK are reported to suffer with it, with the term covering everything from fatigue and breathlessness to muscle and joint pain
