Being vaccinated for Hep B twice?

October 26, 2010 3:05 PM

Is it possible for a Hepatitis B vaccine to be ineffective? Are there any risks to being vaccinated twice?

I just had a standard STD test done, and was told my something-or-other levels are low ("below 1") which indicates that I have not been vaccinated for Hep B, and should do so.

I distinctly remember being vaccinated, though. There was a big campaign in 7th grade back in the early 1990s, complete with a little video that I still remember: "Hepatitis B is a real bad rap". I am really almost 100% sure I got the shots. They told me it was very unlikely I had been vaccinated given my test results.

At their recommendation I booked an appointment to go ahead with the tests. Is there anything for me to worry about? Suppose they screwed something up and I have already been vaccinated after all, is there any risk to doing it again? Or should I just relax and go ahead?

posted by anonymous to health & fitness (9 answers total)

IANAD(Y). Immunity gained through vaccination can wane over time. I had a series of Hep B vaccinations way back when, and when I had my titer tested (the amount of antibodies present in my system), they were less than the amount required to be considered immune (10, I think). And I wasn't sure if I had received all 3 shots the first around either, so to be cautious, I had all three redone. Maybe you didn't receive all three?

This is not medical advice, but I would just go ahead with it.
posted by greatgefilte at 3:20 PM on October 26, 2010

There's no risk to being vaccinated again - I've had my MMR series re-done, as well as having my Twinrix (that's both Hep B and Hep A vaccination combined) re-done, that's six shots all over again (that's what you get for losing records, ugh). I'm fine. I will warn you that if you get the twinrix (Hep A and Hep B combined), your arm will probably be uncomfortable, because it's a bigger shot.

The reason that you get the series of 3 shots is because with the first shot, something like 95% of people seroconvert (meaning they develop antibodies against the virus), with the second shot that becomes like 98.5%, then the last shot is like 99.9%. so you get 3 shots to be double-dog sure that you make antibodies against it, so that your body will have a sufficiently awesome reaction if you get exposed to the virus. and yes, you get boosters because your immunity can decline.

There is a chance that you might get the series of shots and NOT seroconvert .. this does happen! a friend of mine just plain old won't get immune to the virus, so she had to sign a waiver for the nursing program saying that she tried, and it won't happen. this is, to my knowledge, pretty rare.

but you can relax! get the series of shots, get a titer drawn afterwards (a blood draw to check for your immunity), if you don't seroconvert, you can talk to your provider more about risk reduction/exposure issues. good on you for being proactive about it - also, if you don't have health insurance, most public health departments will have Hep B shots partially or totally subsidized.
posted by circle_b at 3:24 PM on October 26, 2010

No - the hepatitis B series shouldn't be able to confer infection. The vaccine doesn't actually contain any of the viral genome, just one of the proteins on the surface of the virus. The protein is unique to the virus and when vaccinated, the body has an immune response. Then, if you have the misfortune of encountering hepatitis B, your body already has antibodies to the virus's surface.

circle_b is right about seroconversion and boosters. I also had a friend in med school who had to get the whole series again because he didn't seroconvert. He's doing fine, and his titers came back that he was seropositive. Go ahead and vaccinate away!
posted by honeybee413 at 3:57 PM on October 26, 2010

I'm a doctor. There's no danger in repeating the hepatitis B vaccine series. I've had the series twice and didn't respond to it. YMMV.
posted by neuron at 4:12 PM on October 26, 2010 [1 favorite]

My kids got vaccinated during the 90's and I vaguely remember receiving a letter about one of the Hep vaccines being recalled due to ineffectivity. I googled "hepatitis vaccine recall" to try to get more information, and it seems there were multiple recalls in the 90's. Maybe your vaccine was in one of those groups?
posted by CathyG at 5:07 PM on October 26, 2010

I've had the whole series done twice. The second time around they through in a 4th shot. No doctor I've spoken to considers it worth me being vaccinated again, though their opinions on whether or not titer levels are a definitive measure of immunity vary.
posted by Lolie at 5:44 PM on October 26, 2010

There's no danger to getting it twice as far as I know. It also can't give you the virus. :)
Baby's get the Hep B series 3 times I think, as in three shots.
posted by doctorwhitecoat at 5:48 PM on October 26, 2010

Similar to CathyC's idea, it could be that the vaccine dose you received as an adolescent had been subjected to temperatures outside the prescribed range - it's supposed to be kept at a certain cold temperature and if it gets warmer than that or if it freezes, it may not be as potent. I would particularly think it would be easy for temperature excursions to happen in the course of a school-based immunization day (if that's where you got yours). In any event, I agree with the other advisors here; no material risk in repeating the series.
posted by lakeroon at 9:47 PM on October 26, 2010

I have been vaccinated twice as an adult, the full set of three shots each time. I work in health care settings, and am quite sure I got the full set the first time. The immunity waned, or didn't take, and so I got it again. It was required for a job, the second time, and they needed proof of immunity. I was surprised to not have coverage, given that I'd had the full set, but my clinician said that it's not all that unusual. I've since talked to other people who got a second full set because the immunity wore off. Make sure you get all three shots, but there's no down side to it.
posted by gingerbeer at 11:53 AM on November 12, 2010