Contraindications to the diphtheria vaccine: 1. Babies with known allergy to any component of the vaccine. 2. Babies with acute diseases, severe chronic diseases or acute exacerbations of chronic diseases, or fever. 3. Babies with encephalopathy, uncontrolled epilepsy and other progressive neurological diseases. 4. Babies with neurological reactions after injection of pertussis, diphtheria and tetanus vaccine. 5. For babies with Children with allergic diseases, especially those with asthma, should not be vaccinated because the vaccination may induce an asthma attack. Pertussis vaccine is to prevent pertussis, diphtheria and tetanus. 3 doses of basic immunization are given from 3 months of age to 12 months of age, with each dose given at an interval of 4-6 weeks and 0.5ml each time.