Covid-19 vaccines and adverse events of special interest
pubmed.ncbi.nlm.nih.gov
pubmed.ncbi.nlm.nih.gov
Some of these results could be because the 1st dose of the vaccine doesn't provide 100% protection, so the increased incidence of illnesses could be a side-effect of COVID infections, not the vaccine itself. Different vaccines provide different amounts of protection against different strains, and we know that the strains have varying effects including some of the observed illnesses.
At the end of the day, COVID-19 kills at a decent rate, and hospitalises at an even higher rate. The whole point of vaccines is to be overall better than the full-blown illness, not to be completely, perfectly, 100.0% harmless. That's impossible! Given a large enough cohort, simply giving a sterile saline injection will cause a non-zero number of "complications", especially in the very elderly or immunocompromised.
Interestingly, ChAdOx1 had comparable numbers for some illnesses to COVID-19, but like many traditional vaccines, it's a modified chimpanzee adenovirus. All viruses cause various health effects, so it's not a surprise that "virus A" and "virus B" are similar in some respects.
This just goes to show that the conspiracy theories around mRNA vaccines were mostly nonsense. They're safer than being infected with a real virus, attenuated or not!