The beneficial aspect of vaccines for human beings is the prevention of infectious diseases; the disadvantage is that they may produce adverse reactions of varying degrees. Vaccination is an effective measure for the prevention of certain infectious diseases, for example, hepatitis B vaccine can prevent hepatitis B, neocollagenic vaccine is used to prevent neocollagenic pneumonia, and BCG vaccine is used to prevent tuberculosis. Effective vaccination is of great significance in preventing the occurrence of infectious diseases and interrupting their epidemics. After vaccination, the main disadvantage is that some adverse reactions may occur, the more common adverse reactions are injection local pain, itching, the emergence of hard nodules, etc., and some of the vaccinated people may have fever, fatigue, dizziness, headache and other systemic reactions. The rarer adverse reactions to vaccination are allergic reactions, such as rash, dyspnea, and in severe cases, anaphylaxis. It may also lead to angioneurotic edema, hematuria, and so on. However, these adverse reactions do not occur in all people; they are less likely to occur and are usually mild. Overall, the benefits of vaccination far outweigh the disadvantages. When vaccinating, attention should be paid to the relevant contraindications, such as fever, acute illness, uncontrolled epilepsy and other patients should avoid vaccination, which can prevent the aggravation of existing diseases and serious adverse reactions. After vaccination should be in the vaccination point to stay half an hour, no discomfort after leaving, after returning home, pay attention to rest, eat a light diet. [Tip] In this article, “new coronary pneumonia, new coronary virus pneumonia” has been renamed to “new coronary virus infection” on December 26, 2022, as announced by the National Health Commission.