Hello, so my dad has been having Chemo and Radiotherapy to treat his anal cancer, he finished treatment the begining of February (he has had chicken pox as a child) My neice and nephews have chicken pox at the moment and we are due to go on holiday with them how long after chemo etc is his immune system compromised? Is he likely to catch chickenpox again if we mix? We were supposed to go on holiday the last 2 years but covid stopped it, but don't want to risk his well being and recovery