If a child has chickenpox, it depends on three aspects: first, whether the adult is immune to the varicella-zoster virus. If the adult has not been vaccinated against chickenpox and has never had chickenpox, he or she is not immune to the varicella-zoster virus and is a susceptible person to chickenpox. Second, the route of contact is not likely to infect chickenpox, chickenpox can be transmitted through respiratory droplets as well as direct contact, if this contact is carried out, it may lead to infection. The period of contagiousness of chickenpox is from 1-2 days before the appearance of symptoms of chickenpox to the complete crusting of chickenpox rash. Only if the above three conditions are met at the same time will the infection be caused.