The CDC has given over $1.5 million in grants to explore potential linksAgain, I think the menstrual cycle stuff has been pretty widely reported, a quick Google news search shows BbC, independent, guardian stories, as well as BMJ articles etc.
The problem with Facebook will likely be people putting unsubstantiated claims on there, although I’m not on Facebook so no idea how their misinformation policy works in practice.
The yellow card reporting is an interesting read as it captures c250k adverse reactions in there (although these are reported unchecked, so not substantiated). But when you dig into it, around 80% of those reactions are sore arm, or fever, chills, which is a completely expected reaction.
there’s also reported reactions on the yellow card system which would have no plausible biological mechanism to be a side effect from the vaccine (e.g. “homosexuality” - I’m not kidding), but it all gets captured there anyway.
Very difficult to disentangle the root causes as stress alone can hugely impact the cycle