The second and third shots of the hepatitis B vaccine are usually given five months apart. China has a large number of hepatitis B patients, and hepatitis B vaccine is an effective way to prevent hepatitis B virus infection. The routine immunization program of hepatitis B vaccine for newborns in China is “0, 1, 6 months”, with 3 doses, the first injection of hepatitis B vaccine should be given as early as possible within 24 hours of the birth of newborns, the second injection is given at the age of 1 month, and the third dose is given at the age of 6 months, and the interval between the second and the third injections is 5 months. In addition, adults need to carry out hepatitis B two half test hepatitis B surface antibody level to assess whether there is a protective effect, when hepatitis B protective antibody titer is less than 10, need to play hepatitis B vaccine booster shot. Hepatitis B vaccine is a national mandatory vaccination, and parents are advised to schedule the vaccination for their children on a regular basis to ensure the protective effect.