I'm not surprised to be honest. He has been burning the candle at both ends, difficult not to when you're Prime Minister during a national crisis. To fight the virus you need to look after yourself and get plenty of sleep, and I mean plenty. The body fights the battle while you sleep. If you try and carry on as normal the virus will take the high ground and gain the advantage. The antibodies will be overwhelmed. After a week you either recover or go downhill. I really hope Boris will get the best treatment and recover soon but he needs to rest.