Small children Visiting new baby

Will you let ppl visiting you in hospital bring there kids ? Like preschool kindergarten age ? Im going to be a new mom and maybe overthinking things but I'm a bit weiry as kids at that age carry lots of germs. I wouldn't put it past my SIL to visit with her daughter as she's been really excited to meet her lil cousin. When the time comes how can I handle the situation without hurting feels ? I know I'm going to be overprotective. 😬😬😬