I'm not an anti-vaxxer, but the story of this guy who came up with a K2 supplement called Koncentrated K makes me think. If you can stand a quick CSB, he's a very highly acclaimed and high-ranking engineer at a major US corporation who was a health nut and discovered in his mid 40s he had a serious hereditary artherosclerosis condition, to the point that his cardiologist told him to get a mistress and travel around the world because he'd be dead in less than a year. Being a classic engineering type mind, he studied like a maniac for many hours every day (he was so highly thought of in his company that they allowed him to do this on the clock) and he finally came up with a regimen that near-miraculously reduced his calcium score to safe levels.
Until one day when he had to go to Russia for work and got a mandatory MMR vaccine. Then his calcium score shot right back up to dangerous levels after years of it being down. He said nothing else changed so the shot had to be what caused it. He said he's not an anti-vaxxer, never had been, and didn't discourage anyone from any vaccine. But just by posting his story, he got attacked online by the usual maniacs.
I'm not an anti-vaxxer either, but this story from someone as conscientious, intelligent, and scientific as this guy makes me wonder. And that was an established vaccine, not a new mRNA one that was tested for less than a year. I have no desire to get the covid shot, but if I did it would be the J&J one for sure.