September 25, 2023 – People with Long COVID have specific biomarkers of their blood, in response to a study published Monday in Nature said.
The findings could possibly be a step toward developing blood tests that may clearly discover individuals with Long COVID in order that specific treatments may be used, the researchers say.
“This is a critical step forward in the development of valid and reliable blood testing protocols for long COVID,” said David Putrino, PhD, lead creator and professor of rehabilitation and human performance and director of the Abilities Research Center at Icahn Mount Sinai Health System.
Researchers on the Icahn School of Medicine at Mount Sinai and the Yale School of Medicine examined blood samples from around 270 people between January 2021 and June 2022. The people had never been infected with COVID, had fully recovered from an infection, or were still showing symptoms no less than 4 months after infection.
Using machine learning, the research teams were able to tell apart between individuals with and without Long COVID with 96% accuracy based on characteristic features within the blood samples, in response to a Press release from Mount Sinai.
People with long COVID had abnormal T-cell activity and low cortisol levels. Cortisol helps people feel alert and attentive, which might explain why individuals with long COVID often complain of fatigue, said an NBC News report on the study.
“It was one of the findings that most clearly distinguished people with Long Covid from people without Long Covid,” said Putrino NBC News.
The study also found that Long COVID appears to reactivate latent viruses reminiscent of the Epstein-Barr virus and the mononucleosis virus, the study said.
The blood tests could allow doctors to develop specific treatments for individuals who have quite a lot of long-Covid symptoms, Putrino said.
“There is no one-size-fits-all solution to treating Long COVID because the disease infiltrates complex systems such as the immune system and hormones,” he said.
The CDC says about one in five Americans who've had COVID still have Long COVID. Symptoms include fatigue, difficulty concentrating, dizziness, digestive problems, and lack of smell and taste.