Safety, reactogenicity and immunogenicity of Francisella tularensis live vaccine strain in humans

We evaluated the safety, reactogenicity and immunogenicity of escalating doses of a new Francisella tularensis Live Vaccine Strain (LVS) lot by scarification (SCAR) or subcutaneously (SQ) in humans. Subjects (N = 10/group) received one dose of LVS via SCAR at 105,107 or 109 cfu/ml or SQ at 102, 103,104 or 105 cfu/ml; 14 subjects received placebo. All doses/routes were well tolerated. When compared to placebo, vaccination with 107 SCAR and 109 SCAR resulted in significantly higher serologic response frequencies, as measured by ELISA for IgG, IgM, IgA and microagglutination; whereas vaccination with 105 SCAR, 107 SCAR 109 SCAR and 105 SQ elicited a significantly higher interferon-γ response frequency.