After receiving one series of hep b vaccinations my titer came back positive 1 year ago. Last week I had to be retested for immunity for a new job and the titer came back 0. How is this possible?
The answer is your antibody level has probably fallen below the limit of detection. You probably still have immunity, but whenever my level falls I get a booster shot. If you are not in a high risk profession then many people think that a booster is not necessary. DTD