Sorry, I said "source" when I should have specified "medical study". Your link reads more like marketing towards vaccination fence sitters than actual science. That isn't your fault though, there just isn't science to share. Why? Because we don't have future traveling time machines.

There is something quite amazing about your link however. The piece (about long term side effects from vaccines) notes the polio vaccine from the 1950s. It somehow omits mentioning Simian Virus 40, the cancer causing virus that was found in the polio vaccine. This vaccine was given to 100 million children and its estimated that 10% to 30% of those doses were contaminated.

I'm sure the doctors assured their parents back then that there were no side effects and certainly laughed off any mention of long term side effects. The price to be paid for trust in these vaccines? Their children growing up to develop brain cancer in their 50s and 60s, decades after they were assured how safe they were.