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Mixed results reported on dengue vaccine
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A prevalent type of dengue in Thailand eluded a vaccine designed to prevent against it, but results of the vaccine against other serotypes show that vaccination against dengue is possible, according to study results published online.
Researchers from Sanofi-Pasteur reported results of a study that was conducted in 4,002 children aged 4 to 11 years, in partnership with the Mahidol University under the patronage of the Thai Ministry of Public Health. Sanofi-Pasteur’s dengue vaccine candidate is a live-attenuated vaccine. The vaccination schedule is three doses given 6 months apart, at 0, 6 and 12 months.
The full analysis of vaccine efficacy against each serotype, in an intent-to-treat analysis, showed vaccine efficacy to be 61.2% against dengue virus type 1, 81.9% against type 3 and 90% against type 4. Serotype 2 eluded the vaccine, researchers said. Analyses are ongoing to understand the lack of protection for serotype 2 in the particular epidemiological context of Thailand.
“While there is still much work to be done, these clinical trials mark a decisive step forward in the development of a safe and effective vaccine,” said Luiz da Silva, director of the Dengue Vaccine Initiative, said in a press release. “We support the progress made by Sanofi-Pasteur, as well as efforts by other organizations, to deliver a vaccine to populations in endemic countries.”
A feature of dengue epidemiology is that the relative prevalence of virus types in a given area is evolving with time. Phase 3 clinical studies of Sanofi-Pasteur’s dengue vaccine candidate are under way, with 31,000 children and adolescents in 10 countries in Asia and Latin America. These studies will generate important additional data in a broader population and in a variety of epidemiological settings to define the best conditions to set up vaccination programs to protect people at risk for dengue.
The FDA has granted fast-track designation to Sanofi’s investigational dengue vaccine. The FDA fast-track designation recognizes that a dengue vaccine would address an important unmet medical need for serious disease.
Disclosure: The study was funded by Sanofi-Pasteur.