Ds 2 caught covid end of Nov 2020 and then again end of May. Second time he had barely noticeable symptoms - a very slight cough. We only tested because he'd been sent home from school to self isolate. This last week he's started with a chesty cough, runny nose and sore throat. I'm in two minds to test again but obviously there's a good chance it will be positive from the previous episode in May. Is there any point re-testing or is it impossible for him to have covid a 3rd time within such a short timescale ?