• Posted October 10, 2024

Could Lingering Infection Be Causing Long COVID?

Some people might have Long COVID symptoms because the coronavirus is still active inside their bodies, a new study finds.

People with wide-ranging Long COVID symptoms were twice as likely to have SARS-CoV-2 proteins in their blood, indicating a persistent infection, researchers found.

Overall, more than 4 in 10 patients with multiple Long COVID symptoms have such evidence of persistent infection, researchers reported Oct. 8 in the journal Clinical Microbiology and Infection.

This could pave the way to effective treatment of Long COVID in some people, said lead researcher Zoe Swank, a postdoctoral research fellow at Brigham and Women’s Hospital in Boston.

“If we can identify a subset of people who have persistent viral symptoms because of a reservoir of virus in the body, we may be able to treat them with antivirals to alleviate their symptoms,” Swank said in a hospital news release.

For the study, researchers analyzed more than 1,500 blood samples collected from about 700 COVID-19 patients.

Those patients who reported Long COVID symptoms affecting their heart, lungs, brain and muscles were twice as likely to still have coronavirus proteins circulating in their blood months after their initial infection, researchers found.

About 43% of people with Long COVID symptoms affecting at least three major systems in the body tested positive for these viral proteins, compared to only 21% of those without Long COVID symptoms, researchers said.

However, that means more than half of patients with Long COVID don’t have a persistent infection, researchers noted.

“This finding suggests there is likely more than one cause of Long COVID,” said principal investigator David Walt, a professor of pathology at Brigham and Women’s Hospital. “For example, another possible cause of Long COVID symptoms could be that the virus harms the immune system, causing immune dysfunction to continue after the virus is cleared.”

The notion that virus can remain in the body and keep causing symptoms isn’t unique to COVID, researchers said.

“Other viruses are associated with similar post-acute syndromes,” Swank said, pointing to Ebola and Zika viruses as examples.

Researchers are now conducting follow-up studies to better understand whether an ongoing infection causes some people’s Long COVID symptoms.

“There is still a lot that we don’t know about how this virus affects people,” said researcher Dr. David Goff, director of the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute. “These types of studies are critical to help investigators better understand the mechanisms underlying Long COVID -- which will help bring us closer to identifying the right targets for treatment.”

More information

The U.S. Centers for Disease Control and Prevention has more about Long COVID.

SOURCE: Brigham and Women’s Hospital, news release, Oct. 9, 2024