About transmission probability

I tried to post using email but I don’t see it anywhere. Sorry if it is duplicated. Please remove another one if it has been posted successfully.


I am a HBV patient who has been taking vemlidy / entecavir for years. I got it from my mother.

My hbv DNA had been in an undetectable state for years, but in a lab test 3 weeks ago, the viral load became 100 IU/ml.

Last weekend, I had “semi unprotected sex” with my girlfriend a few times. I put on condom a little late during the sex. I made the common mistake assuming she has been vaccinated. Another reason was I think my viral load should be in a safe range. I cannot describe how regrettable I am.

It turns out she does not have antibody so she got the first hbv vaccine immediately.

She is now too anxious to sleep. At the beginning I was not worried because I know the risk should be very low.
But now I am also very anxious. The fact that I don’t want to lose her make me less rational. I am super worried about the worst case that is , she gets chronic hepatitis b like me.

My questions are

  1. What is the chance she got infected? How can I make her less worried? Can someone use probability to measure the risk?

  2. Will HBV DNA increase from 100 IU / ml to, say a very large number in two weeks assuming entecavir is completely not working?

  3. Do we still need to wait three months to completely not worry?

Both of us are over 30.

Thank you so much.

Hi @vitafusion,
Welcome to the community and sorry to read about your challenge. It is hard to predict chances when it comes to virus and what they might do or not do. The first is that with a viral load of 100 from 3 weeks ago, we don’t know what that value is today or was a week ago. Can you affect someone with a viral load of 100? Yes of course. Is it highly likely to happen, that is hard to tell. Probably this is a case of low risk exposure.

But on the other hand, most people who get exposed to HBV in adulthood have a 90% chance of clearing the virus and do not develop a chronic infection. 5-10% adults do. At least if your girlfriend was exposed she has a 90 percent chance at clearing the virus and will not develop a chronic infection. If she is still concerned, it might be too late to take something for post-exposure prophylaxis. It is good that she got her first vaccine dose, let’s remain hopeful that she was not exposed. And that she can develop antibodies from the vaccine.

I hope you are following your doctor’s orders, taking your medications as prescribed, and you are not skipping doses? It is important you take your medicine daily as prescribed. Have a conversation with your provider about this sudden increase in your viral load to get to the bottom of it. Thanks, Bansah1.

I also read that HBIG (Hepatitis B immune globulin) injection can be given after exposure to help prevent HBV infection. I believe the injection should be given with 24 hours after exposure. As stated elsewhere, over 90% of adults can fight off an infection by himself/herself. This process may take up to a year, in extreme cases.