I have, as a retired Canadian military officer, received many dozens of a wide variety of vaccines in my adult life so that I was deployable at a moment's notice, and could be expected to survive most common infections. I had all the usual vaccines, yellow fever, hepatitis, pneumonia (X2), shingles (X2), and multiple annual flu and COVID MRNA vaccines. None of them has given me more than a slightly sore muscle at the point of injection.
Vaccines do a world of good. They prevent polio, smallpox, shingles in the elderly, pneumonia, TB, measles, mumps, rubella, typhoid, yellow fever, and so on. Millions upon millions of people have gotten various vaccines for many decades now. I'd say the heavy, bloated, and rather compelling preponderance of evidence is that they are safe and effective, two qualities anyone should hope a vaccine has.
It is known that some are allergic or have other negative reactions to some of the contents of typical vaccines. Those people should be cautious and watchful. But most people will make good use of them.
I almost lost our fourth grandson to RSV. It was touch and go, but the nurses and doctors saved him. Aged people, those with compromised immune responses or with some comorbidities, should consult their doctors and follow their advice. That would be the only medical advice I will ever give on this forum... to follow the experts.