“…Several explanations for this observation have been suggested before [9,18] and include intrinsic differences in the vaccine formulations such as in the antigenic content and/or the excipients added. Ultimately, regardless of their relative differences in immune response, it is well established that both Encepur ® and FSME-IMMUN ® elicit effective immune responses against TBE after a complete primary vaccination series in adults and children [9,11,17,19,20], even if used interchangeably [9,18]. What has not been well established, however, is the duration of antibody persistence following primary immunization with these vaccines.…”