Scientists are optimistic about new evidence into what is causing long COVID, a panel of research experts brought together by the New York State Department of Health said.
They proposed many theories on what might be driving long COVID. A role for a virus “cryptic reservoir” that could reactivate at any time, “viral remnants” that trigger chronic inflammation, and action by “autoimmune antibodies” that cause ongoing symptoms are possibilities.
In fact, it’s likely that research will show long COVID is a condition with more than one cause, the experts said during a recent webinar.
People might experience post-infection problems, including organ damage that takes time to heal after initial COVID-19 illness. Or they may be living with post-immune factors, including ongoing immune system responses triggered by autoantibodies.
Determining the cause or causes of long COVID is essential for treatment. For example, if one person’s symptoms persist because of an overactive immune system, “we need to provide immunosuppressant therapies,” Akiko Iwasaki, PhD, said. “But we don’t want to give that to someone who has a persistent virus reservoir,” meaning remnants of the virus remain in their bodies.
Interestingly, a study pre-print, which has not been peer reviewed, found dogs were accurate more than half the time in sniffing out long COVID, said Iwasaki, professor of immunobiology and developmental biology at Yale University.
If one of the main theories holds, it could be that the coronavirus somehow remains in the body in some form for some people after COVID-19.
“A weakened immune response to an infection may mean that you have cryptic reservoirs of virus that are continuing to cause symptoms,” she said during the briefing. Hornig is a doctor-scientist specializing in epidemiology at Columbia University in New York City.
“That may explain why some patients with long COVID feel better after vaccination,” because the vaccine creates a strong antibody response to fight COVID-19, Iwasaki said.
For other people with long COVID, it’s not the virus sticking around but the body’s reaction that’s the issue.
“Fortunately, through the global research effort, we are now really starting to expand our understanding of how long COVID manifests, how common it is and what the underlying mechanisms may be,” Purpura said.