@ujm While I understand the concern, you are starting off with a false assumption. We aren’t the guinea pigs. There already were guinea pigs. Tens of thousands of people have tested the vaccine, and after many months the worst side effects were a few weeks of feeling bad. On the flip side, an equal number of people did not get the vaccine (the control group) and many more of them fell ill in a much more severe manner (COVID-19).
I agree with @charliehall. Although all the effects may not yet be known, it is a near-certainty that the dangers of not taking the vaccine far outweigh the dangers of taking it.
As for demographics that may be in danger, such as kids and people with certain illnesses, the vaccine isn’t approved for them and they won’t be taking it until it is.