This story resonated with me. Like your son's school, both my kids' schools reported COVID cases within 3 days of opening. Thankfully, neither of them were close contacts and both are fully vaccinated so I'm not fearful of hospitalization if they do get infected.
Yet I do worry about this constant uncertainty, as there will likely be more infections. I'm hoping my community gets to 80% fully vaccinated or more. I have no idea what parents are doing in places where other students (and parents!) refuse to vaccinate and refuse to mask. It's a frustrating time to be a parent sending kids to public school.