The National Disease Control Bureau and six other departments decided to adjust the immunization schedule for the whooping cough-diphtheria-tetanus combined vaccine nationwide starting from January 1, 2025. This adjustment changes the current immunization schedule, which involves administering one dose of the acellular whooping cough-diphtheria-tetanus combined vaccine at 3 months, 4 months, 5 months, and 18 months, and one dose of the diphtheria-tetanus combined vaccine at 6 years old, to an immunization schedule where one dose of the DTP vaccine is given at 2 months, 4 months, 6 months, 18 months, and 6 years.