The Omicron variant of coronavirus is less likely to cause long COVID than the Delta strain, new research suggests.
The study, conducted by King’s College London, found that the odds of experiencing long COVID were between 20% and 50% lower in Omicron when compared with the Delta variant, depending on age and time since vaccination.
Researchers used data from the Zoe COVID Symptom study and lead author Dr Claire Steves said: “The Omicron variant appears substantially less likely to cause long COVID than previous variants but still one in 23 people who catch COVID-19 go on to have symptoms for more than four weeks.
“Given the numbers of people affected it’s important that we continue to support them at work, at home and within the NHS.”
Analysis showed that 4.4% of Omicron cases were long COVID but more than double (10.8%) of Delta cases showed signs of long COVID.
However, the number of people who had long COVID was higher during the Omicron period because of the number of infections of the variant during its peak in the UK between December 2021 and February 2022.
The Office of National Statistics estimates the number of long COVID sufferers increased from 1.3 million in January 2022 to 2 million as of 1 May.
The National Institute for Health and Care Excellence (Nice) defines long COVID as having new or ongoing symptoms four weeks or more after initial infection.
Symptoms include fatigue, shortness of breath, loss of concentration and joint pain or impacted day-to-day activity which for some people can be severely limiting.
The study, which was published in a letter to The Lancet, identified 56,003 UK adults who tested positive between 20 December 2021 and 9 March 2022, when Omicron was dominant.
Researchers compared these to 41,361 cases first testing positive between 1 June and 27 November 2021, when Delta was dominant.