Just 29% of people hospitalised with Covid make a full recovery after a year, a worrying study has found.
Hundreds of thousands who were treated for the virus are still suffering from symptoms such as fatigue, muscle pain, poor sleep and breathlessness, experts believe.
The findings show the legacy of the pandemic is going to be "huge", one of the study authors said.
A team of researchers from Leicester University found that women were most likely to still be feeling the impact, while obese people were also hardest hit.
It shows the desperate need to properly treat Long Covid, experts say.
Rachael Evans, one of the report's authors, said: “Given that more than 750,000 people have been hospitalised in the UK with Covid-19 over the past two years, it is clear from our research that the legacy of this disease is going to be huge."
Fellow author Prof Chris Brightling added: “Without effective treatments, long Covid could become a highly prevalent long-term condition."
The study followed the recovery of more than 2,000 people who had been treated at one of 39 NHS hospitals for Covid-19.
Ms Evans said: “We found that only 25% of people who had been hospitalised with Covid-19 had fully recovered five months after they had been discharged, a figure that increased only slightly – to 29% – after a year.

“That was a very limited rate of recovery in terms of improvements in mental health, organ impairment and quality of life. It was striking.”
Those who required mechanical ventilation were among those who had poorer rates of recovery, the study found.
Ms Evans said: “If you are a man, you are more likely to be hospitalised if you get Covid-19 but have a [higher] chance of feeling better when you get out.
“We found being female and obese were major risk factors for not recovering after a year.”
Prof Louise Wain said the findings highlight the need for effective treatment for the most serious Covid cases.
She said: “No specific therapeutics exist for long Covid and our data highlights that effective interventions are urgently required.”