Young kids around my newborn

Sarah
So i have a niece thats 4 years old, and shes very excited about her baby cousin coming but shes in preschool and gets sick all the time. Should i not let her around my newborn until my baby gets her first set of shots? Or atleast not let her touch my babys face or hands? Is it rude of me to not let my neice around her or to limit her time with her.