Please learn to distinguish between Vaccination and Vaccine.

Some vaccines have proven to be a big benefit for humanity. And some vaccines may just unleash hell on mankind.

Don't be naive and say vaccination as whole is safe and benefitial. If you look close with an unbiased mind you will see that it is by far easier to do harm by injecting an (to you) unknown agent into your system and therefore bypassing all defence systems.

The pre-vaccine age was a time when poor hygiene and diets, along with unsanitary living conditions created an environment where disease pathogens could thrive and be easily transmitted. If the only factor that changed between then and now was the addition of vaccines, you might have a valid argument.