Hepatitis B is an infectious disease caused by hepatitis B virus infection of liver cells, and hepatitis B vaccination is an important means of preventing and controlling the incidence and transmission of hepatitis B. The vaccination should be administered before and after the injection. Hepatitis B vaccination precautions include two aspects before and after injection. 1. Precautions before vaccination (1) On the day of vaccination, if there are symptoms such as fever, dizziness, headache, nausea, weakness of limbs, etc., the vaccination should be postponed and go to the hospital as soon as possible; (2) If there are systemic diseases such as heart disease, liver or kidney disease and blood disease, or low-birth-weight babies and immunocompromised, etc., it is recommended to determine whether or not to receive Hepatitis B vaccine under the guidance of a doctor; (3) If a newborn baby is not vaccinated with hepatitis B vaccine in time due to certain circumstances and the period of time is more than 1 month, it is recommended to go to the hospital for medical consultation to clarify whether there is any infection, and then the doctor will determine whether it is possible to be vaccinated or not; (4) Before hepatitis B vaccination, it is recommended to check the infection status of hepatitis B virus, if already infected, there is no need for hepatitis B vaccination. 2. Precautions after vaccination (1) Within 30 minutes after vaccination, the vaccinee needs to observe his/her physical condition at the site, so that he/she can be treated in time in case of acute allergic reactions such as breathlessness, coughing and dizziness; (2) In order to avoid redness, swelling, infection and other symptoms at the vaccination site, it is necessary to pay attention to not scrubbing the injection site for a short period of time and keep the vaccination site dry; (3) After vaccination, in order to avoid headache, limb pain, nausea and other uncomfortable reactions, the vaccinee should avoid strenuous exercise in the near future.