The difference between Long COVID and adverse reactions to the COVID vaccine appear to be at best rather uncertain. In October 2021, 5 months after getting the Maderna shots I went from running 2 plus miles every other day to painfully walking shorter distances. I began taking Relief Factor and felt some improvement but not enough to run. It was over month after I had to stop running before I discovered that leg pains are an admitted adverse reaction to the vaccine, confirmed by the CDC. Only last month, 18 months after the leg pains showed up, was I able to resume my full former running regimen.