If a child is already 6 years old and has not been vaccinated, the child should be vaccinated in a timely manner, because although the child is already 6 years old, the immune function will be improved. But there are still many diseases that can occur, such as chickenpox, which can be vaccinated against. In addition, if a child has not received the MMR vaccine, it is also important to catch up on the vaccination because the probability of viral mumps is very high in children who are 6 years old. Therefore, children who have not received the full vaccination at the age of 6 weeks should go to the local department for catch-up vaccination.