Safety of and Immune Response to a Tick-Borne Encephalitis Vaccine (LGT(TP21)/DEN4) in Healthy Adults

Inclusion Criteria: * Willing and available to be followed for the duration of the study * Willing to use acceptable means of contraception * Good general health Exclusion Criteria: * Pregnancy or breastfeeding * Clinically significant neurologic, heart, lung, liver, rheumatologic, autoimmune, or kidney disease * Behavioral, cognitive, or psychiatric disease that, in the opinion of the investigator, affects the ability of the volunteer to understand and cooperate with the study * Blood disease * History of migraine headaches * History of encephalitis * Alcohol or drug use that has caused medical, occupational, or family problems within 12 months prior to study entry * History of severe allergic reaction or anaphylaxis * Emergency room visit or hospitalization for severe asthma within 6 months prior to study entry * HIV-1 infected * Hepatitis C virus infected * Hepatitis B surface antigen positive * Known immunodeficiency syndrome * Use of corticosteroids or immunosuppressive drugs within 30 days prior to study entry. Participants who have used topical or nasal corticosteroids are not excluded. * Live vaccine within 4 weeks prior to study entry * Killed vaccine within 2 weeks prior to study entry * Blood products within 6 months prior to study entry * Investigational drug or vaccine within 3 months prior to study entry * Previously received a licensed or experimental yellow fever, tick-borne encephalitis, or dengue vaccine * Surgical removal of spleen * History of tick-borne encephalitis * History of dengue virus infection or other flavivirus infection (e.g., yellow fever virus, St. Louis encephalitis, West Nile virus, Japanese encephalitis virus) * Other condition that, in the opinion of the investigator, would affect the participant's participation in the study