Hepatitis B surface antibody 50mIU/mL, need to take Hepatitis B Vaccine booster shot, if after the first Hepatitis B Vaccine booster shot, the Hepatitis B surface antibody in the body is higher than 200mIU/mL, there is no need to take this vaccine again, if it is lower than 200mIU/mL, then you need to take this vaccine one more time. Hepatitis B surface antibody of 50mIU/mL can be checked 1 month after the booster shot of Hepatitis B vaccine. If the hepatitis B surface antibody is greater than 200 mIU/mL, you can skip the second booster shot of hepatitis B vaccine. If the surface antibody is less than 200mIU/mL, it is recommended to take the second booster shot of hepatitis B vaccine. It is recommended to go to the hospital regularly to recheck the level of hepatitis B surface antibody in the body, and get hepatitis B vaccination in time if necessary to effectively protect the body from hepatitis B virus infection.