Kinetics of the immune response after primary and booster immunization against tick-borne encephalitis (TBE) in adults using the rapid immunization schedule

Abstract

A total of 222 adult subjects aged 19–51 years were enrolled in this multi-center, phase III study to evaluate immunogenicity and safety of the first booster immunization with a new tick-borne encephalitis (TBE) vaccine. This was an extension study that followed subjects who had received primary immunization 12–18 months previously with either the new or formerly licensed TBE vaccine according to the rapid immunization schedule (i.e. on Days 0, 7 and 21). Compared to the levels of primary immunization, prior to first booster, neutralizing TBE antibodies (geometric mean titers, GMTs) of both vaccination groups had remained on a high level and were far above the detection limit of the neutralization test used. All subjects showed a sharp increase of TBE antibodies following the booster. The booster was well tolerated by the subjects. Conclusion: These results in terms of both immunogenicity and safety indicate that the TBE vaccination with this new TBE vaccine can be used effectively and safely in adults. A long lasting immunity can be concluded from the strong immune response following the first booster.