Stéphanie Longet is an immunologist and a COVID researcher at the University of Saint-Etienne in France, and just like 10-20% of adults who were infected with the virus, she continues to have symptoms well after her infection has resolved – a condition known colloquially as long COVID.
“I got COVID one year ago and I developed some persistent symptoms,” she says. “I cannot work too long. My legs are quickly exhausted. In the morning it feels like I had run a marathon during the night, and I didn’t do anything, I just slept.”
Longet and other scientists don’t exactly know why some people develop long COVID while others don’t, but preliminary research released in medRxiv in July suggests that genetics plays a role.
The new research, which was an international collaboration between dozens of scientists, describes how some people carry a version of a single gene, FOXP4, that is associated with developing long COVID. Longet calls the new research an “important element” in understanding why some people’s COVID symptoms seemingly never resolve.
A surprising finding about long COVID
Long COVID only affects a small percentage of people who are infected with SARS-CoV-2, but the scope of the pandemic means that many millions of people are suffering. Roughly 25 million people in the U.S. and over 17 million people in Europe have long COVID symptoms, with many more in other parts of the world.
There isn’t a universally agreed upon definition for what is considered long COVID – people experience a range of different symptoms including “fatigue, muscle pain, intestinal disorders and brain fog” and for different periods of time according to Longet, who was not involved in the new research. That’s made the disease difficult for scientists to fully understand.
But the new research adds to the growing body of work showing that genetics can influence COVID outcomes. It was only a few weeks ago when NPR reported that genetics might make some people resistant to developing any COVID symptoms at all.
Jill Hollenbach, an immunologist at the University of California, San Francisco, was one of the scientists who led the research on asymptomatic COVID. She says she was “surprised and excited” about the new long COVID findings.
“The fact that the authors were able to detect this association [between the FOXP4 gene and long COVID], I think, is spectacular,” Hollenbach says.