Comment by francisofascii

My gut reaction (pun intended) or guess on what causes Long Covid is a viral reservoir, possibly in the gut, that the immune system cannot fully clear. Low serotonin is then a downstream effect from the chronic stress on the body. Approx. 90% of serotonin found in the human body is located in the (GI) tract. So people and doctors will throw SSRIs at the problem, and maybe that will relieve some symptoms, but will not address the fundamental cause. Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10171832/