NEW YORK, Oct 17, (Agencies): As the world grapples with the possibility of another seasonal surge in coronavirus cases, the medical community continues to investigate the perplexing condition known as long COVID. This enigmatic ailment presents a wide array of symptoms persisting long after a COVID-19 infection has cleared, including fatigue, loss of sexual desire, diminished senses of taste and smell, chest pain, and chronic cough. The precise origins of long COVID, an umbrella term encompassing around 200 diverse symptoms, remain elusive.

However, scientists at the University of Pennsylvania have put forward a hypothesis linking long COVID to diminished levels of serotonin, a neurotransmitter that influences mood, memory, sleep, digestion, blood clotting, and sexual desire. This theory posits that the enduring symptoms may be attributed to disrupted serotonin levels. Estimates indicate that between 10% and 30% of individuals may experience some form of long COVID after recovering from a coronavirus infection, with this risk having somewhat declined since the early days of the pandemic.

In a bid to explore the role of serotonin, researchers conducted a comprehensive analysis involving 58 patients who had endured long COVID for up to 22 months post-infection. Their blood samples were compared to those of 30 individuals with no post-COVID symptoms and 60 patients in the early stages of a coronavirus infection. The findings revealed that serotonin levels underwent alterations immediately following a coronavirus infection, a phenomenon akin to other viral infections. However, individuals with long COVID exhibited a notable difference: serotonin failed to rebound to its pre-infection levels.

Diminished serotonin levels can disrupt the vagus nerve system, responsible for transmitting signals between the body and the brain. Additionally, serotonin plays a crucial role in short-term memory. Researchers posit that reduced serotonin levels may give rise to memory issues and other cognitive challenges often experienced by individuals grappling with long COVID.

Dr. Christoph Thaiss, a lead author of the study and assistant professor at the Perelman School of Medicine at the University of Pennsylvania, noted, "Even if not everybody experiences difficulties in the serotonin pathway, at least a subset might respond to therapies that activate this pathway."

If indeed low serotonin levels are responsible for long COVID, some experts are optimistic that interventions can improve the condition. Dr. Maayan Levy, another lead author and assistant professor of microbiology at the Perelman School of Medicine, is planning a clinical trial to explore this further. The trial will involve testing fluoxetine, a selective serotonin reuptake inhibitor (SSRI) marketed as Prozac. This endeavor will join a series of ongoing studies aimed at unraveling the mysteries of long COVID.