Not only that, but we’re talking about a risk/reward calculation between vaccination and the virus, not just whether or not it’s possible that people could have adverse reactions to a vaccine.
On the risk side for not getting vaccinated, the virus is obviously less risky for most younger people than it is for older people. However, you could find many anecdotes about young people having very serious cases of COVID, or even dying. For the risk of getting vaccinated, the vaccines are very safe, but there are still minuscule chances that certain populations might have higher risk of adverse reactions.
On the reward side of getting vaccinated, you prevent the spread of disease, and you reduce the risk of getting a severe case and/or dying down to basically 0. I guess the reward of not getting vaccinated is you don’t have to worry about the very unlikely chance of a significant adverse reaction to the vaccine.
At any rate, this is something the FDA and CDC looks at before issuing authorizations and recommendations, respectively. We’ve seen that when they want to investigate a problem, they will pause the use of certain vaccines in order to better understand whether certain reactions might have something to do with the vaccines.
Also, let’s remember that requiring vaccinations for school or other participation isn’t uncommon at all. The Pfizer vaccine is likely to be fully FDA-approved by the fall, so you won’t be able to say it’s an “experimental vaccine” as a talking point against vaccination.