Long COVID less likely after omicron compared to delta — but risk remains, study says
Lingering COVID-19 symptoms — commonly called long COVID — may be less likely after an omicron variant infection compared with the delta variant, a new observational study has found.
However, the risk still remains as omicron is highly infectious. The variant and its subvariants have made up the majority of virus cases over the past several months, according to the Centers for Disease Control and Prevention.
In the study, nearly 5% of people infected with omicron experienced long COVID symptoms at least four weeks after testing positive for the coronavirus, according to the U.K.-based research published June 16 in The Lancet.
Meanwhile, roughly 10% of those who were infected with the delta variant reported “new or ongoing” symptoms of COVID-19 weeks after their infection appeared, the study involving researchers from King’s College London found.
Some common long COVID symptoms are breathing abnormalities, cough, and malaise and fatigue, according to a prior study conducted by FAIR Health, a nonprofit based in New York City, McClatchy News reported.
A separate study conducted by the CDC found “respiratory symptoms and musculoskeletal pain” to be the most common lingering virus symptoms, McClatchy News reported.
In this latest study, authors wrote that “we believe this is the first peer-reviewed study to report on long COVID risk associated with infection by the omicron variant.”
The work examined 56,003 U.K. adult residents who tested positive for COVID-19 due to the omicron variant in Dec. 20, 2021, until March 9 and 41,361 people who were infected with the delta variant during June 1, 2021, and Nov. 27, 2021, according to the study.
The findings are based on the study participants’ self-reported symptoms which were recorded in a COVID Symptom Study app created by King’s College.
More on the study
One study author, Dr. Claire Steves, told NPR that a question researchers sought to address was “Is long COVID as common ... in the delta period [as it is] in the omicron period?”
The delta variant has not circulated in the U.S. for most of 2021, according to CDC data estimates. It made up 0.1% of virus cases as of March 26.
In the study, all research participants had an average age of 53 and a similar rate of comorbidities.
Certain risk factors associated with long COVID — such as comorbidities, vaccination status and body mass index — were accounted for, according to researchers.
While the study found the odds of long COVID is lower with omicron, there is a “caveat,” Steves explained to NPR.
The “omicron variant has spread very rapidly through our populations, and therefore a very much larger number of people have been affected.”
“So the overall absolute number of people who are set to go on to get long COVID, sadly, is set to rise,” Steves added.
In the research, authors wrote one limitation of the study was how there was no “direct testing of infectious variants.”
Participants who tested positive for delta were infected up until Nov. 27, 2021, according to the study, which is when omicron was first discovered in the U.K.
Ultimately, researchers concluded long COVID cases “will inevitably rise.”
This story was originally published June 17, 2022 at 8:57 AM with the headline "Long COVID less likely after omicron compared to delta — but risk remains, study says."
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