Viral shedding, in which someone becomes contagious and can pass a virus to someone else, is sometimes a concern when parents think about live vaccines.
Fortunately, viral shedding is not usually a problem because:
the MMR vaccine doesn't cause shedding
the chicken pox vaccine can rarely cause shedding if a child develops a vesicular rash after getting vaccinated, but can be avoided by avoiding direct contact with the rash
the rotavirus vaccine only causes shedding in stool, so can be avoided with routine hygiene techniques, such as good hand washing, and if immunocompromised people avoid diaper changes, etc., for at least a week after a child gets a rotavirus vaccine
transmission of the live, nasal spray flu vaccine has not been found in several settings, including people with HIV infection, children getting chemotherapy, and immunocompromised people in health-care settings"
Another concern for parents is whether healthy children should get live vaccines if they will be exposed to someone else who has a problem with their immune system. Fortunately, except for OPV and the smallpox vaccine, which aren't typically used, children who live with someone who has an immunologic deficiency can get most vaccines in the routine childhood immunization schedule, such as MMR, Varivax, and the rotavirus vaccines. "