I don't have the original source but I read about a double bind test of one of the COVID-19 vaccine side effects. Only half of the test subjects received the vaccine (the other saline), but something like two thirds of the test subjects reported side effects. There isn't any doubt that long COVID is real, but it's more than likely that many of the people that report symptoms don't actually have it. There has been so much talk about long COVID in the media, that people expect to have it; so the media is working as a nocebo.