The nasal spray vaccine given to children has a tiny dose of live virus. This means if you are having the kind of chemo that compromises your immune system you should avoid contact with children who have had the vaccine for 1-2 weeks. However if you have little ones at home you can ask for them to be given the injection instead as this is not live.
Same problem with rotavirus. I started a course of chemo (eribulin) in mid-2014 when this vaccine for babies was very new. We had to postpone a visit to our new granddaughter because she had had the jab [EDIT: sorry, I think it was a nasal spray… d’oh chemo brain!]
I had a lot of difficulty finding the correct information about the vaccine.