How can I check if I’m immune to hepatitis B? If you don’t know whether or not you are immune, your doctor can do a blood test to check. Most babies born after 1 May 2000 should have been given the hepatitis B vaccine at birth and several follow-up doses. Children who were at school after this date may have been given the vaccine through a school immunisation program. Find out more about vaccination against hepatitis B References SA Health. (2019, July 2). Hepatitis B vaccine frequently asked questions. Updated 2 December 2019