Some of the vaccines for infants can be co-vaccinated, and different types of vaccines can be given at different sites at one time. Infants generally need to be based on the time of birth to develop vaccination time, such as 3 months need to complete the vaccination of DPT vaccine and polio vaccine, if the scheduled time of vaccination of infants with fever, vomiting, diarrhea phenomenon, need to postpone the vaccination, thus appearing and other vaccination time conflict, if the two types of vaccines do not have contraindications for joint vaccination, you can be once again vaccinated. However, it is generally recommended to try to receive one vaccine at a time, so as not to confuse the adverse reactions of different vaccines. If joint vaccination is required, different sites should be selected for vaccination, such as the right and left upper limbs.