Serotonin signaling: a new player and therapeutic target beyond Long-haul coronavirus disease

During the coronavirus disease 2019 (COVID-19) pandemic, a subset of individuals continues to suffer from symptoms including fatigue, post-exertional malaise, dyspnea, bone loss, and memory and neurocognitive dysfunction for months and even years after infection. This clinical phenomenon has been labeled 'Long-haul COVID' or 'post-acute sequelae of COVID-19 (PASC)'; however, the underlying pathophysiological mechanisms remain unclear. In a recent study published in Cell, Wong et al. revealed that viral infection and type I interferon-driven reduction of peripheral serotonin impaired hippocampal responses and short-term memory through vagal neurons in patients with PASC. Therefore, the study provided novel insights into how serotonin links persistent viral inflammation with the neurocognitive symptoms of Long-haul COVID and actionable therapeutic targets for patients with PASC.