Is the virus 100% safe? Weigh them against each other and account for who the kids could spread it to, how much vaccine uptake there is, immune compromised they could spread it to who can't be protected well from the vaccine, etc.
If the risk of harm to kids from the virus is say 1%, and 0.1% for the vaccine, then it would still be better to go unvaccinated since the risk of catching the virus is most likely less than 10% once adults are vaccinated.
Is the virus 100% safe? Weigh them against each other and account for who the kids could spread it to, how much vaccine uptake there is, immune compromised they could spread it to who can't be protected well from the vaccine, etc.