It is not recommended that the second dose of hepatitis B vaccine be given a few days in advance, as this may result in a decrease in the protective effect of the hepatitis B vaccine or other symptoms in the body, and it is recommended that the vaccine be administered under the supervision of a doctor. Hepatitis B vaccine prevents infection with the hepatitis B virus by injecting inactivated hepatitis B virus into the body, which can stimulate the body’s immune system to produce protective antibodies against the hepatitis B virus. Hepatitis B vaccine is usually given as a second and third dose at 1 month and 6 months respectively after the first dose. It is not recommended to get the second dose of Hepatitis B vaccine a few days in advance. Early vaccination may cause over-immunization due to the body’s constitution, which may easily lead to a decrease in the protective effect of the Hepatitis B vaccine, or other uncomfortable symptoms in the body. The second injection of hepatitis B vaccine is not recommended to be given a few days in advance, and it is recommended to be given in strict accordance with the stipulated intervals, and if there is a need to change the date of vaccination, it should be done under the guidance of the doctor.