Safety, Reactogenicity and Immunogenicity of Francisella tularensis Live Vaccine Strain in Humans

Abstract 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 10 5 ,10 7 or 10 9  cfu/ml or SQ at 10 2 , 10 3 ,10 4 or 10 5  cfu/ml; 14 subjects received placebo. All doses/routes were well tolerated. When compared to placebo, vaccination with 10 7 SCAR and 10 9 SCAR resulted in significantly higher serologic response frequencies, as measured by ELISA for IgG, IgM, IgA and microagglutination; whereas vaccination with 10 5 SCAR, 10 7 SCAR 10 9 SCAR and 10 5 SQ elicited a significantly higher interferon-γ response frequency.