Vaccination against tick-borne encephalitis (TBE): influence of simultaneous application of TBE immunoglobulin on seroconversion and rate of adverse events.

One hundred and twenty-one of 128 enrolled healthy adult subjects were immunized against tick-borne encephalitis (TBE) either by TBE vaccine on days 0 and 28 (61 subjects) or simultaneously by TBE vaccine plus TBE immunoglobulin on day 0 plus TBE vaccine on day 28 (60 subjects). Formation of TBE antibodies were measured in ELISA on days 0, 28 and 56. On day 28 median TBE antibodies were twice as high in the vaccine group (2400) as in the vaccine plus immunoglobulin group (1200). Adverse events were more often observed after the first vaccination than after the second in both groups. In the vaccine group, adverse events after the first vaccine dose were remarkably more frequent (45% of these subjects reported 38 adverse events) than in the group who received vaccine plus immunoglobulin (25% of these subjects reported 18 adverse events). All types of adverse events (chills, flu-like symptoms, injection site pain) were reported less frequently in the vaccine plus immunoglobulin group. After the second vaccination the rate of adverse events was 7% in both groups. Seroconversion was achieved in all subjects on day 56 except one subject in the vaccine plus immunoglobulin group. Simultaneous application of TBE vaccine plus TBE immunoglobulin can be recommended for persons who need immediate protection plus active TBE vaccination.