For the boys who have already had it this year it shouldn't be a issue. Young healthy and highly active immune systems: symptomatic reinfection inside 6 months chance would be close to 0.
If they haven't had it then for the sake of a potential first flag they need to get their 4th shot.
Less, but def not close to zero.
How dockery would it be to have a double chance for the first time in 9 years only to have a covid crisis on the Eve of finals….