Lyme disease has a long, storied history in alternative medicine and anti-vax communities. I would not be surprised if many of the people seeking the vaccine early were in those communities and entered with a distrust of vaccines, but thought the risk of Lyme disease outweighed their perceived risk of the vaccine. Once they got the vaccine they fixated on it as the source of their problems.

This exact pattern has been playing out with the COVID vaccine and the HPV vaccine. There are communities who are convinced that every medical problem they had since receiving the HPV vaccine is due to the vaccine, even though they’re all having different health problems that also occur in the overall population.

It's a bit of a stretch to describe These claims were investigated by the FDA and the Centers for Disease Control, which found no connection between the vaccine and the autoimmune complaints. as "written off as a health panic".

Of course you can just say they didn't investigate it enough or whatever, you aren't trying to make a reasoned argument and thus don't need to exercise reason.

A problem with vaccines and the public is that when you perform any intervention on many many people, some will happen to (randomly) suffer some issue. To them, it is obviously causation, regardless of what the math (that they do t understand) says.