As I understand it, pretty much the only people who aren't eligible for vaccination in the US are those who've had an allergic reaction to a previous dose of the vaccine or one of its ingredients specifically and under-12s, though there are some additional observation requirements for people with a history of certain other allergic reactions. The former is quite a small group and children are at really low risk: https://news.sky.com/story/covid-19-only-0-005-of-covid-infe...