A flu infection can develop long-term symptoms just like "long Covid", a study has found.
Researchers from Oxford University studied the health records of people with a flu or Covid diagnosis - mainly from the US.
Each group was made up of around 100,000 subjects who sought treatment for symptoms of either respiratory illness three to six months after infection.
Symptoms for both groups included fatigue, headache, anxiety, and breathing difficulties, BBC reports.
The study suggests Covid patients are more likely to have long-term symptoms.
Forty-two per cent of subjects in the Covid group had at least one long-term symptom. Of the people surveyed with flu, that number dropped to just 30 per cent.
There may be a higher rate of "long" symptoms for Covid as patients are more likely to seek healthcare for them, the study found.
The way Covid indicators have been recorded through the pandemic may also have an effect, the research says.
The groups included patients who would have been quite unwell with the viruses, so it should not be considered representative of the general population.
But the study did find both Covid and flu can produce "long" symptoms which last longer than the initial illness.
Professor Paul Harrison, one of the lead researchers, told the BBC: "Many of us who have experienced flu know how you don't always feel completely better as quickly as you've been hoping or expecting to."
The research only viewed the incidence broadly, focusing on signals of "long" illnesses, and did not record how long sufferers had been ill for.
The final report did not record the severity of the symptoms of each virus.
Evidence has grown to suggest Covid could have devastating impacts on patients on a longer-lasting timescale than initially thought.
Experts said the study revealed evidence on the long-lasting effects of flu, but admitted further research is needed into the "long" Covid issue.
Max Taquet, another lead researcher on the study, said: "Long-term symptoms from flu have probably been overlooked before."
Another report yesterday repealed over 10 per cent of secondary school pupils who had Covid-19 have suffered ongoing symptoms.
Over a third of school staff who contracted the deadly virus continue to show the effects in the coming weeks and months, known as Long Covid.
The most common symptoms are tiredness and a general weakness, Hull Live reported.
School staff were more likely to experience a shortness of breath than pupils, according to the study of some schools in England.
The analysis was based on 5,117 survey responses between July 2 and July 26.
Nearly 3,500 pupils and over 1,600 staff in primary and secondary school took part in the study.
