 - Licensed vaccines are not exclusionary but should be given at least 14 days before or after immunization applies to each of the 3 scheduled TBEV injections for inactivated vaccines and 30 days before or after immunization with any live vaccines. This is in order to avoid potential confusion of adverse reactions. Given the nature of the work these study subjects engage in, exemptions to this proscription may be granted on a case-by-case basis after discussion between the Investigator and the IRB.. 