Immunogenicity and Safety of an Inactivated Rift Valley Fever Vaccine in a 19-Year Study
Abstract
An investigational, formalin-inactivated Rift Valley fever (RVF) vaccine, known as The Salk Institute-Government Services Division (TSI-GSD) 200 vaccine, was administered to 1860 at-risk subjects (5954 doses) between 1986 and 2004 as a three-dose primary series (days 0, 7, and 28) followed by booster doses as needed for declining titers. An initial positive serological response (PRNT80 > or = 1:40) to the primary series was observed in 90% of subjects. Estimate of the PRNT80 response half-life in initial responders to the primary series by Kaplan-Meier plot was 315 days after the primary series dose 3. Differences in a serological response were observed at 2 weeks after dose 3 of the primary series between vaccine lots and for gender (women> men); a trend was observed for age (<40 years). When response to the primary series was measured by PRNT50 titer > or = 1:40, nearly all subjects (99.1%) responded. In individuals not initially responding to the primary series (PRNT80 < 1:40), a response was observed in most subjects after receiving only one booster dose. Immune response (all subjects) to subsequent booster doses for a declining titer (PRNT80 < 1:40) was 98.4%. The vaccine was well-tolerated; vaccine-related adverse reactions were generally mild and self-limited. Differences in adverse events were observed with vaccine lot and sex. The data support the safety and immunogenicity of the inactivated RVF vaccine, and may serve as a standard of comparison for immunogenicity and safety for future RVF vaccines.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 26, 2011
- Accession Number
- ADA541035
Entities
People
- Denise P. Clizbe
- Ellen Boudreau
- Janice M. Rusnak
- Paul Gibbs
- Phillip Pittman
Organizations
- United States Army Medical Research Institute of Infectious Diseases