Positive for hep B core antigen and anxious

Just diagnosed or new to the community
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Hello, I’m a new member and I can’t thank you all enough for being here as a resource. I was really shocked and confused when I first found out I tested positive for Hep B. I’m not sure how to start a new post under “Just diagnosed” because I do have questions about what I should do. After reading many posts and information here I’ve calmed down because I understand things a bit better, although I am still at a loss on how I got Hep B.

I was vaccinated against Hep B in 1997. I’ve had many Hep B blood tests since then, all negative (except for surface antibodies showing immunity from the vaccine). In 2019 the test showed my surface antibodies were waning (“borderline immunity”), so I got a booster shot. I had a titer done for surface antibodies after the booster and the results showed >10,000 mIU and immunity.

As late as 2023 my tests showed immunity from Hep B (positive surface antibodies and negative core antibodies and negative surface antigen). Yet in May 2025 I just tested positive for core antibodies as well as surface antibodies. Negative for surface antigen and unable to detect Hep B DNA through a PCR test. The core antibodies test was repeated just to make sure it wasn’t a lab error. It wasn’t.

Please forgive me if I’m just not understanding things correctly, I’m very anxious. How is it possible that I was vaccinated against Hep B (with a booster as late as 2019 and a titer showing a robust number of surface antibodies), and I end up getting Hep B (as shown by positive core antibodies) 4 years later? I didn’t engage in risky activities either. I had no symptoms of acute hepatitis.

I am extremely grateful that I haven’t tested positive for the Hep B surface antigen, and I have no detectable Hep B DNA. Does it mean I’m no longer contagious? It seems so based on what I’ve read here. But after having “immunity” from Hep B before and yet getting Hep B, I’m skeptical about everything now.

Would anyone here recommend I see a hepatologist or infectious disease doctor? I asked my primary care doctor, and she was at a loss to explain it. She just said I could get regular bloodwork every 6 months to make sure it didn’t “come back.” But I thought it couldn’t come back once you’ve had it and have surface antibodies and no antigens and no viral load?

Please forgive me for all the questions and if I’m not being clear. I’m lost and really don’t know what I should be doing. Thank you for listening. :green_heart:

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Hi @djm55,
Welcome to the community. Don’t feel sorry about not being able to post stuff. So, your test results show that you do not have hepatitis B, and you have antibodies. The care antibody test shows that you were exposed sometime in the past. There is no evidence that you are currently infected. You may have been infected and cleared it before getting vaccinated decades ago. Some people, unfortunately, are only tested for antibodies but not the surface antigen before they are given the vaccine. This might be what happened in your case: that you did not get the other tests done before you were vaccinated.

There is no harm in seeing a hepatologist for further discussions. It will be helpful. I hope this helps. Bansah1

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Hi @djm55,

Welcome to the forum and thanks for sharing your story. Yes, a positive anti-HBc antibody test would suggest you were previously exposed and it could have been while you had protective antibodies. The vaccine protects against getting a chronic infection, but not necessarily neutralizing any exposure.

There are many ways to be exposed, for example through scratches, dental procedures or other medical procedures.

Being HBsAg negative, you are considered as not able to transmit the virus.

Hope this helps,
Thomas

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