Study of Serotonin Levels Offers Hope for Long COVID Treatment

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Oct. 17, 2023 -- Oct. 17, 2023 – New research has found that long COVID is associated with lower levels of circulating serotonin, and those lower levels of serotonin could be relevant to neurological, cognitive and memory symptoms associated with long COVID, the researchers say.

The study, which was conducted at the Perelman School of Medicine at the University of Pennsylvania, was published in the journal Cell.

Studying the biological changes in people with long COVID could help in the development of treatment, The New York Times reported.

This possible biological pathway could unite many of the major theories of what causes long COVID-19 such as lingering remnants of the virus, inflammation, increased blood clotting and dysfunction of the autonomic nervous system, the Times wrote.

Christoph Thaiss, PhD, a lead author of the study, said, “All these different hypotheses might be connected through the serotonin pathway. Even if not everybody experiences difficulties in the serotonin pathway, at least a subset might respond to therapies that activate this pathway.”

The scientists analyzed blood of 58 long COVID patients who had symptoms for three months to 22 months after they were infected. The researchers then compared those results to blood of 30 people who had no post-COVID symptoms and 60 who were in the early stages of infection.

Levels of serotonin and other metabolites change right after infection, said Maayan Levy, PhD., a lead author and assistant professor of microbiology at the Perelman School of Medicine, in The Times. Serotonin is the only “significant molecule that did not recover to pre-infection levels” in people with long COVID, the Times reported.

The study was small, which means the results are qualified and need further validation.