DPT is a vaccine used to prevent three diseases: pertussis, diphtheria and tetanus. The DPT vaccine, also known as adsorbed cell-free combined DPT vaccine, protects against multiple diseases at the same time. After vaccination, the body can be induced to produce an immune response. After completing the basic immunization program (3 shots), the body can effectively prevent the pathogens from infecting the body and causing pertussis, tetanus and diphtheria. Pertussis vaccine is used for children between 3 months and 6 years of age, but it is contraindicated for children who are allergic to the active ingredients of the vaccine or who are suffering from an exacerbation of the disease. After vaccination, children may experience discomfort such as mild fever, redness, swelling and pain at the site of vaccination, etc. Parents need to pay attention to care, which can usually be relieved on their own.