Vaccinations should not be given 28 days apart. The same vaccine should be given at least 30 days apart between doses because it takes at least 30 days for a vaccine to detoxify at one time. Vaccination with another vaccine during the detoxification and establishment of a new immune response can easily affect the immune response, thus causing discomfort or reduced immunity. Therefore, parents must follow medical advice when administering vaccinations and must not forcibly change the vaccination schedule. After vaccination, local hard nodules and baby fever may occur after individual vaccination, which are common vaccination reactions and most of them require special intervention and will subside naturally in about two days.