• Safety: The frequency of adverse events in this RVF vaccine study will be evaluated for all intent-to-treat subjects; Immunogenicity: Measurement is the 80% plaque-reduction neutralization titer (PRNT80). [ Time Frame: AEs: recorded through day 28 after each dose; SAEs: duration of study; Immunogenicity: PRNT80 at 28 days after dose 3. Part B: Pre-6-month dose and 12 month titer. Any RVF illness in a vaccinated subject will be recorded for duration of study. ] [ Designated as safety issue: No ]
  

Biological: RVF
Part A: RVF vaccine will be given as three 1.0-ml subcutaneous primary series injections, with doses on day 0, once on days 7-14, once on days 28-42 (the third dose will be given at least 21 days after the second dose).Part B: Subcutaneous 1.0-ml booster doses (maximum of four boosters over 12 months) will be given if the volunteer fails to respond to the primary series with a PRNT80 ≥ 1:40 or annually if titer wanes to < 1:40.

Study Objectives:

The objectives of this two-part, primary immunization and booster dose, study are to continue to collect safety data on Rift Valley Fever (RVF) Vaccine, Inactivated (TSI-GSD 200); and, to continue to collect immunogenicity data on Rift Valley Fever (RVF) Vaccine, Inactivated (TSI-GSD 200) and analyze interim data to determine whether a 6-month dose is indicated; and, to provide potential protection for personnel at risk for occupational exposure to the RVF virus and collect data on incidence of occupational RVF infection (subclinical and clinical) in immunized personnel.

Inclusion Criteria:

Parts A & B:

• At least 18 years old, or if active military duty, 17 years old,
• Females of childbearing potential must agree to have a urine pregnancy test within 48 hours before receipt of each dose of vaccine. The test results must be negative. Females will be advised not to become pregnant for 3 months after the primary series and each booster dose, and must not be breast-feeding,
• Subject must be actively enrolled in the SIP
• Subjects must be at risk for exposure to RVF virus,
• Subjects must have an up-to-date (within 1 year) medical history, physical examination, and laboratory tests in their charts and be medically cleared for participation by an investigator. Examinations or tests may be repeated within 1 year at the discretion of the enrolling physician.
• Volunteer must have signed and dated the approved informed consent.

Additional Inclusion Criteria for Part B:

• Completion of primary series and any follow-up titer (PRNT80) < 1:40 from the current or a previous RVF IND 365 protocol.

Exclusion Criteria

Parts A & B:

• Clinically significant abnormal lab results including evidence of Hepatitis C, Hepatitis B or carrier state, or elevated liver function tests.
• Personal history of immunodeficiency or current treatment with immunosuppressive medication, at the discretion of the physician.
• Confirmed HIV infection.
• Any medical condition that, at the discretion of the physician, may jeopardize the safety of the volunteer.
• Any serious or life-threatening allergies to any component of the vaccine: formalin,human serum albumin,neomycin,streptomycin
• Administration of any other vaccine within 28 days of any dose of RVF vaccine.
• Any unresolved adverse event resulting from a previous immunization.

Additional Exclusion Criteria for Part B:

• An adequate PRNT80 (≥ 1:40) after completion of primary series.