Immunity to hepatitis B means your body can fight off the hepatitis B virus if you are exposed to it. This protection comes from antibodies, which are proteins your immune system makes to recognize and destroy the virus. You can develop immunity in two ways: through vaccination or by recovering from a past hepatitis B infection.
The hepatitis B vaccine is one of the most effective vaccines available. It works by teaching your immune system to recognize the virus without making you sick. After you complete the vaccine series, usually 3 doses over 6 months, your body produces hepatitis B surface antibodies. These antibodies stay in your bloodstream and provide long-term protection against the virus.
Blood tests can measure whether you have these protective antibodies. Knowing your immunity status helps you understand if you are protected or if you need vaccination or a booster dose. This is especially important for healthcare workers, people with liver disease, and anyone at higher risk of exposure to hepatitis B.