Most vaccines are inactivated and the main component is protein, so people who are allergic to them should not be vaccinated. In addition, people who have some chronic diseases or who are in the throes of chronic diseases cannot receive vaccines. Some vaccines have age restrictions and also need to be noted: 1. The presence of chronic diseases: people with active tuberculosis, severe hepatitis or in the active stage of severe heart disease, as well as those with acute or chronic kidney disease are not recommended to receive vaccination; 2. In the attack period of chronic diseases: fever, various acute diseases, and the acute attack period of chronic diseases, it is recommended to suspend vaccination and consider vaccination when the body has fully recovered; 3. Vaccine allergy: people with serious adverse reactions after vaccination, such as acute allergic reactions, which can be manifested by skin lesions and respiratory difficulties, as well as those with diseases such as urticaria and angioneurotic edema, are not recommended for vaccination; 4. Bleeding: people with thrombocytopenia or out blood system diseases, such as purpura, which can easily cause bleeding, are not recommended for vaccination; 5. Mental diseases. Vaccination is not recommended for people with convulsions, epilepsy, and other progressive neurological disorders, or when psychiatric disorders are present in their past history. Vaccination is also not recommended for people who do not have the above diseases but have a family history of the above diseases; 6. Defective or impaired immune system: Vaccination is not recommended for people with autoimmune diseases, such as congenital or acquired immune deficiency, systemic lupus erythematosus, lymphoma, leukemia, etc.; 7. For example, the new crown vaccine is not recommended for people under 12 years old. In addition, women who are pregnant or breastfeeding should be vaccinated with caution, and it is recommended to ask the relevant authorities before choosing whether or not to vaccinate in order not to affect the growth and development of the fetus or infant.