don't drive cars, they can crash and it can be fatal while having other side effects, however rare they are.
However, vaccine for incredibly rare or non-existent disease isn't likely worth the tradeoff. Or maybe a particular vaccine is too dangerous or experimental.
Anyway, if the CDC recommend a vaccine for something, it's likely that they had looked into it and decided that the upside is worth more than the risk.
1. You can become invalid
2. You can kill buss of kids
3. You can go to jail
4. It can be very hard on your finance
5. You can have your car stolen
6. You can lose your nerves
7. There are bunch of diseases involved due to gasses
etc...
Basically, every single person I know had some problem with the car. Probably the best not to have them.
I found it highly pleasurable.