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I received my vaccine years ago--am I still protected?

If it has been years since you have been vaccinated, you may need or may request a hepatitis B surface antibody titer blood test to confirm that you are still protected. A person is considered protected if they have a positive anti-HBs or HBsAb test result greater than 10 mIU/mL. Sometimes these test results are under 10 and there is concern whether these low levels will still provide protection against hepatitis B. Anti-HBs or HBsAb test results can decrease over time, but an individual can still be protected even if the test results are less than 10 mIU/mL.

If your test results are low, your doctor may recommend a booster shot or a repeat of the series. If you confirm you completed the vaccine series, you can get a booster dose of the vaccine. Your surface antibody level will be tested again 1 or 2 months after the booster. If the blood test result is greater than 10 mIU/mL, then you are protected and will not require an additional booster shot in the future. (Ongoing studies show continued immunity for 30+ years) If a booster shot does not result in a level greater than 10, then complete the remaining two-doses of the vaccine series and recheck the levels again after 1-2 months. Retain a copy of the anti-HBs titer test as proof of protection.


Find more Frequently Asked Questions here

Page updated 02/09/2022