according to a new study published in JAMA.
The global study also found that about 6% of people with symptomatic infections had long COVID in 2020 and 2021. The risk for long COVID seemed to be greater among those who needed hospitalization, especially those who needed intensive care.
“Quantifying the number of individuals with long COVID may help policy makers ensure adequate access to services to guide people toward recovery, return to the workplace or school, and restore their mental health and social life,” the researchers wrote.
The study team, which included dozens of researchers across nearly every continent, analyzed data from 54 studies and two databases for more than 1 million patients in 22 countries who had symptomatic COVID infections in 2020 and 2021. They looked at three long COVID symptom types: persistent fatigue with bodily pain or mood swings, ongoing respiratory problems, and cognitive issues. The study included people aged 4-66.
Overall, 6.2% of people reported one of the long COVID symptom types, including 3.7% with ongoing respiratory problems, 3.2% with persistent fatigue and bodily pain or mood swings, and 2.2% with cognitive problems. Among those with long COVID, 38% of people reported more than one symptom cluster.
At 3 months after infection, long COVID symptoms were nearly twice as common in women who were at least 20 years old at 10.6%, compared with men who were at least 20 years old at 5.4%.
Children and teens appeared to have lower risks of long COVID. About 2.8% of patients under age 20 with symptomatic infection developed long-term issues.
The estimated average duration of long COVID symptoms was 9 months among hospitalized patients and 4 months among those who weren’t hospitalized. About 15% of people with long COVID symptoms 3 months after the initial infection continued to have symptoms at 12 months.
The study was largely based on detailed data from ongoing COVID-19 studies in the United States, Austria, the Faroe Islands, Germany, Iran, Italy, the Netherlands, Russia, Sweden, and Switzerland, according to UPI. It was supplemented by published data and research conducted as part of the Global Burden of Diseases, Injuries and Risk Factors Study. The dozens of researchers are referred to as “Global Burden of Disease Long COVID Collaborators.”
The study had limitations, the researchers said, including the assumption that long COVID follows a similar course in all countries. Additional studies may show how long COVID symptoms and severity may vary in different countries and continents.
Ultimately, ongoing studies of large numbers of people with long COVID could help scientists and public health officials understand risk factors and ways to treat the debilitating condition, the study authors wrote, noting that “postinfection fatigue syndrome” has been reported before, namely during the 1918 flu pandemic, after the SARS outbreak in 2003, and after the Ebola epidemic in West Africa in 2014.
“Similar symptoms have been reported after other viral infections, including the Epstein-Barr virus, mononucleosis, and dengue, as well as after nonviral infections such as Q fever, Lyme disease and giardiasis,” they wrote.
Several study investigators reported receiving grants and personal fees from a variety of sources.
A version of this article first appeared on Medscape.com.