Safety and immunogenicity of dry powder measles vaccine administered by inhalation: a randomized controlled Phase I clinical trial.

BACKGROUND: Measles is a highly infectious respiratory disease which causes 122,000 deaths annually. Although measles vaccine is extremely safe and effective, vaccine coverage could be improved by a vaccine that is more easily administered and transported. We developed an inhalable dry powder measles vaccine (MVDP) and two delivery devices, and demonstrated safety, immunogenicity, and efficacy of the vaccine in preclinical studies. Here we report the first clinical trial of MVDP delivered by inhalation. METHODOLOGY: Sixty adult males aged 18 to 45 years, seropositive for measles antibody, were enrolled in this controlled Phase I clinical study. Subjects were randomly assigned in 1:1:1 ratio to receive either MVDP by Puffhaler(®) or by Solovent™ devices or the licensed subcutaneous measles vaccine. Adverse events (AEs) were recorded with diary cards until day 28 post-vaccination and subjects were followed for 180 days post-vaccination to assess potential serious long term adverse events. Measles antibody was measured 7 days before vaccination and at days 21 and 77 after vaccination by ELISA and a plaque reduction neutralization test. RESULTS: All subjects completed the study according to protocol. Most subjects had high levels of baseline measles antibody. No adverse events were reported. MVDP produced serologic responses similar to subcutaneous vaccination. CONCLUSIONS: MVDP was well tolerated in all subjects. Most subjects had high baseline measles antibody titer which limited ability to measure the serologic responses, and may have limited the adverse events following vaccination. Additional studies in subjects without pre-existing measles antibody are needed to further elucidate the safety and immunogenicity of MVDP.