Let me tell you about how seriously we take vaccine safety in the world. The whole of public health is COMMITTED to delivering vaccines safely.
Examples:
1) "please sit here for 15 minutes" after the vaccine
(30 minutes if you have a history of allergies). The chance of vaccine anaphylaxis is about 3 per million doses. The chance of a FATAL anaphylactic reaction is about 2% of those. So we have you sit there, epipen nearby, for a 1 in ~30 million chance. There is no verified anaphylactic death to a COVID vaccine in the US or Canada's ENTIRE HISTORY (hundreds of millions of doses given).
2) COVID surveillance systems discovered the J&J clot issue. Six reported cases in 6.8 million doses caused the initial pause (1 per million) by April 13, 6 weeks after it was launched. At that frequency, there was NO WAY to detect it with a clinical trial. By the time the investigation stopped. By March 2022, there were 60 confirmed cases with 9 deaths. (In fact, the RATE of J&J TTS doesn't exceed baseline rates of TTS, it was the incredible epidemiologists recognizing the cluster of central venous sinus thrombosis, positive anti-pf4 without heparin exposure, and mostly women 30-40s). We now believe it was about 3.55 cases per million doses. And now you can't get J&J anymore, because the SURVEILLANCE WORKED and it was determined to be too unsafe for public use. Withdrawn at the company's request. In total: ~60 serious events (2 per million doses) lead to its withdrawal. (for mRNA vaccines, TTS is felt to be 0.0057 per million doses, or one in 175 million doses given.
3) AstraZeneca/Vaxzevria (same mechanism) UK moved to 30+ in April 2021, then 40+ in May, on roughly 1 in 100,000 in young adults; several countries dropped it entirely.
4) RSV vaccines and Guillain-Barre Syndrome - probably the best example. Early VAERS showed ~4.4/~1.8 (2 different vaccines) per million doses. Studies showed 9-22 excess cases per million doses, ACIP narrowed the recommendation from 60+ to 75+, and the FDA requires a GBS warning (even though the at the time the best study showed that the difference may not be statistically significant, and we now know there was a statistical signficance).
6) mRNA vaccines and myocarditis - Finland, Sweden, Denmark, Norway suspended it <30y and FDA extended dose intervals. Determined the age gradient it affected almost immediately, and modified practice because of it. It is now felt to be a real signal, concentrated in young males after dose 2 during the primary series, and now (most recent analysis) 1/37,000 in 12-24 and still a very reassuring prognosis when it occurs (according to one Norwegian nationwide follow-up study)
So hey, when we say vaccines are "Safe" what we mean is:
1) OUR CURRENT BEST EVIDENCE IS THAT THEY ARE SAFER THAN ALMOST EVERYTHING YOU DO
2) We are watching VERY VERY VERY closely and we will YOINK TF OUT OF ANY VACCINE if we are concerned of even a MINIMAL CONCERN
The public should be very reassured that these systems are in place all over the world (virtually every modern country), they are being very carefully monitored and they've all generally agreed on the same result (though sometimes approach it differently).