FTM; worries about unvaccinated kids with new baby

Hello,

I know vaccines are a sensitive topic for some, I’m not here to debate them, I’m asking for opinions please.

I am vaccinating my son who is due 8/1/19. My sisters 4 children are not vaccinated and it has my husband and I all worried. I don’t know how to talk to her about my expectations with all of them. I want them all to be involved, but I worry about them possibly spreading something to him before he can be properly vaccinated.

Has anyone else had to deal with this?

Any advice, outside of your opinions on vaccines, is greatly appreciated!!

TIA