At least one in 10 people infected with the highly contagious Omicron Covid-19 variant experienced the effects of long Covid in the six months following infection, an expansive study has found.
That is lower than the 30 per cent most researchers cited throughout the pandemic, suggesting that long Covid was more common and severe in those infected with earlier variants.
The study, supported by the National Institutes of Health and published in Jama, involved about 10,000 people in the US and focused on the symptoms of long Covid with the aim of better defining it and potentially treating those suffering from long-term effects.
“Americans living with long Covid want to understand what is happening with their bodies,” Rachel Levine, US assistant secretary for health, said in an NIH news release on Thursday.
Out of 9,764 participants – including 8,646 infected with Covid-19, and 1,118 uninfected – more than 30 symptoms were identified within six months or longer after infection.
Researchers narrowed the long Covid symptom list to 12 through a patient-reported scoring system.
Post-exertional malaise – the feeling of extreme exhaustion after minor mental or physical tasks – was the leading long Covid symptom in the study.
This is followed by fatigue, brain fog, dizziness, gastrointestinal symptoms, heart palpitations, lack of sexual desire or energy, loss of smell or taste, thirst, chronic cough, chest pain and abnormal movements.
Research has been carried out globally, from the UK to Israel, on the mysterious post-Covid disease, though it is still unknown why some people get long Covid while others do not.
The study's authors hope their research validates those who are suffering: A Brookings Institution report last year estimated that between two and four million people in the US are unable to work due to long Covid.
“This study is an important step toward defining long Covid beyond any one individual symptom,” study author Leora Horwitz said in a press release.
“This approach – which may evolve over time – will serve as a foundation for scientific discovery and treatment design.”
The authors also hope the study's results will be a starting ground for doctors aiming to better identify long Covid and medical researchers looking into how to treat symptoms.
The World Health Organisation and countries around the world, including the US, have ended public health emergencies for the Covid-19 pandemic despite it continuing to be a threat.