With a median age of 23 years, the study is unique for evaluating mostly healthy, young adults and for its rare look at long COVID in a university community.
The more symptoms during a bout with COVID, the greater the risk for long COVID, the researchers found. That lines up with previous studies. Also, the more vaccinations and booster shots against SARS-CoV-2, the virus that causes COVID, the lower the long COVID risk.
Women were more likely than men to be affected. Current or prior smoking, seeking medical care for COVID, and receiving antibody treatment also were linked to higher chances for developing long COVID.
Lead author Megan Landry, DrPH, MPH, and colleagues were already assessing students, staff, and faculty at George Washington University, Washington, who tested positive for COVID. Then they started seeing symptoms that lasted 28 days or more after their 10-day isolation period.
“We were starting to recognize that individuals ... were still having symptoms longer than the typical isolation period,” said Dr. Landry. So they developed a questionnaire to figure out the how long these symptoms last and how many people are affected by them.
The list of potential symptoms was long and included trouble thinking, fatigue, loss of smell or taste, shortness of breath, and more.
The study was published online in Emerging Infectious Diseases. Results are based on records and responses from 1,388 students, faculty, and staff from July 2021 to March 2022.
People had a median of four long COVID symptoms, about 63% were women, and 56% were non-Hispanic White. About three-quarters were students and the remainder were faculty and staff.
The finding that 36% of people with a history of COVID reported long COVID symptoms did not surprise Dr. Landry.
“Based on the literature that’s currently out there, it ranges from a 10% to an 80% prevalence of long COVID,” she said. “We kind of figured that we would fall somewhere in there.”
In contrast, that figure seemed high to Eric Topol, MD.
“That’s really high,” said Dr. Topol, founder and director of the Scripps Research Translational Institute in La Jolla, Calif. He added most studies estimate that about 10% of people with a history of acute infection develop long COVID.
Even at 10%, which could be an underestimate, that’s a lot of affected people globally.
“At least 65 million individuals around the world have long COVID, based on a conservative estimated incidence of 10% of infected people and more than 651 million documented COVID-19 cases worldwide; the number is likely much higher due to many undocumented cases,” Dr. Topol and colleagues wrote in a long COVID review article published in Nature Reviews Microbiology.
About 30% of study participants were fully vaccinated with an initial vaccine series, 42% had received a booster dose, and 29% were not fully vaccinated at the time of their first positive test for COVID. Those who were not fully vaccinated were significantly more likely to report symptoms of long COVID.
“I know a lot of people wish they could put COVID on the back burner or brush it under the rug, but COVID is still a real thing. We need to continue supporting vaccines and boosters and make sure people are up to date. Not only for COVID, but for flu as well,” Dr. Topol said