can a person get infected by Hepatitis B while taking Hepatitis B vaccine if the needle is infected with Hepatitis B virus.


1 Answer 1


It's hard to imagine such a scenario but the answer is yes. If you haven't completed the vaccination series and therefore haven't developed immunity yet, then you remain susceptible to infection.


  • How quickly after the final dose of the vaccine do you have immunity? Presumably this depends on if it is the two or three dose schedule.
    – StrongBad
    Jul 13, 2017 at 19:04
  • @StrongBad The immunity it confers is a curve beginning with the first shot that rises until some weeks after the last one, so there isn't a day when you're not immune and the next day you are. And keep in mind that not everyone develops immunity from the vaccine. Some people simply never do even after two series of shots.
    – Carey Gregory
    Jul 13, 2017 at 23:55
  • I think your answer is incomplete then since it is much more complicated then simply completing the series, but has to do with how far into the immunity development process you are. The initial studies may have looked at immunity levels as a function of time in order to get the correct dosages and time intervals.
    – StrongBad
    Jul 14, 2017 at 0:11
  • @StrongBad However the studies were done doesn't matter. Immunity is never a yes/no question for any disease. It's always a fluctuating curve that varies over time, circumstances, and health of the individual. It's entirely possible for someone who showed a strong, positive titer to HBV to die of it due to being immunocompromised by drugs, disease, AIDS, etc.
    – Carey Gregory
    Jul 14, 2017 at 1:50

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