Clinically, many children develop fever after vaccination. This is mostly a normal physiological manifestation, and as parents, there is no need to worry too much. Fever is an increase in body temperature above the normal range and is divided into infectious fever and non-infectious fever. The fever caused by vaccination is a kind of non-infectious fever. The vaccine given to a newborn baby is an attenuated or inactivated bacterial or viral biological agent, which allows the body to acquire protective antibodies against pathogens and become immune to diseases. At the same time, some components of the bacteria or viruses in the vaccine can stimulate the body’s immune response and cause fever in infants. Such fevers are classified as physiological and pathological. Physiological fever usually does not exceed 38.5℃, and it mostly appears within one day after vaccination, and the course of the disease does not exceed two to three days. Three to four days have not yet reduced the fever, or two days after the fever began, more pathological fever, but also may be a sudden disease coupled with the time of vaccination. At this time, it is necessary to pay attention to it and seek treatment at the hospital in time. Therefore, we should treat fever after vaccination rationally and not take medicine “blindly”. In addition, after vaccination, redness, swelling and scabbing may appear in the injection area, so it is necessary to keep the scabbed and swollen area clean and hygienic, and pay attention not to get wet. Red rash may also appear on other parts of the body, and it will disappear after two days, so don’t worry too much.