Why did my niece develop Hepatitis B infection despite being vaccinated?
Q: I have a 3 years old niece who had completed her entire course of hepatitis B vaccination but was recently diagnosed with hepatitis B. Her blood reports showed the following - HBeAg: Hep B Envelope Antigen, serum by CMIA - Negative Anti HBe - Ab to hep B Envelope Ag, serum - Positive. May be the vaccination did help but it didn't prevent the virus entirely. Could I get clarity on this?
A:The data (reports) supplied below do not dilate on the protective antibody (antibody against Hepatitis B surface antigen) levels against Hepatitis B surface antigen; thus is not possible to ascertain if the vaccination received by the individual was protective. One can only be certain that vaccination has been effective by evaluating the protective antibody levels after receiving the full course. All vaccinations do not offer life long protection (for example, typhoid) in which the protective efficacy is only 90% and the protective levels usually last only for 2-3 years. Another additional facet is that if the exposure load (for example, typhoid) is very high, then it can overcome the immunity provided by a vaccine. However, this is unlikely for Hepatitis B vaccine. Thus if the individual did develop Hepatitis B infection after immunization course, the possible reasons would be that he/she did not produce enough antibodies (vaccine was not potent, administered improperly, or was already harbouring the infection before immunization.