Safety and immunogenicity of SC599, an oral live attenuated Shigella dysenteriae type-1 vaccine in healthy volunteers: results of a Phase 2, randomized, double-blind placebo-controlled trial
- PubMed: 16213632
We conducted a Phase 1b study to evaluate the immunogenicity and safety of two live attenuated tetravalent dengue vaccines in healthy adult volunteers. After one injection, all subjects reported systemic reactions consistent with a mild dengue-like syndrome. Seven volunteers developed dengue 3 viraemia after vaccination. All subjects developed a neutralizing antibody response against serotype 3 with partial response against other serotypes. The trial was stopped early (after 10 subjects enrolled) due to formulation issues, which were related to the dengue 3 vaccine component. Managing viral interference and balancing attenuation to produce acceptable tetravalent immunogenicity with minimal reactogenicity may be a recurring problem for future multivalent live vaccines.