One in 20 infected with mild Covid in the first wave are STILL battling illness, study shows

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’.

It comes as separate research also suggested Covid booster jabs are just 52 per cent effective at preventing infection after four weeks. By five months this stands at 20 per cent.

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. 

‘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 separate research also suggested Covid booster jabs targeting the Omicron variants prevented infection in just over half of people. 

Writing in the New England Journal of Medicine, US researchers found effectiveness stood at 52.2 per cent after four weeks and prevented hospitalization in 66.8 per cent of cases. 

But infection prevention fell to 32.6 per cent after 10 weeks and just 20.4 per cent after 20 weeks.

By comparison, effectiveness at preventing hospitalization decreased to 57.1 per cent after 10 weeks.

Dr Danyu Lin, study lead author and professor of biostatistics at University of North Carolina, Chapel Hill, said: ‘The relatively low effectiveness of the XBB.1.5 vaccines against the JN.1 subvariant, together with the waning effectiveness over time, underscores the need for new vaccines targeting the JN.1 strain.’

The JN.1 variant, dubbed Juno, has been dominant in the UK and USA for the past few months. 

Covid cases have continued to slowly increase across the UK, in recent weeks 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 Juno. 

But 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.