The release of preliminary results from a second large phase III efficacy trial of the Sanofi Pasteur candidate dengue vaccine last Tuesday, brought dengue endemic countries one step closer to having a safe, functional vaccine to help them control the disease, which is the most important mosquito-borne virus disease in humans. The results of the trial, which involved more than 20,000 children aged 9-16 in 5 tropical American countries, followed a publication 2 months earlier by Capeding et al in the Lancet of a similar trial involving 5 Asian countries. The results of both trials were consistent with each other, suggesting that this candidate vaccine may have public health utility in helping control dengue in endemic countries.
According to the press release, results of this newest trial showed a slightly higher overall efficacy of 60.8% in preventing virologically confirmed symptomatic dengue infection after three doses. Efficacy against the four serotypes was quite similar to the Asian trial, and ranged from 42.3% for DENV-2 to 77.7% for DENV-4. As in previous trials, Sanofi Pasteur reports a very good safety profile. More important, and consistent with the previous efficacy study in Asia, there was high vaccine efficacy in preventing severe dengue disease, and a higher vaccine efficacy in those individuals who had previous dengue infection. Finally, there was a 80.3% reduction in hospitalization. The full results of the American trial will be published in the coming months.
The results of these two phase III efficacy trials of the Sanofi Pasteur vaccine are encouraging, and represent a milestone in efforts to develop an effective, safe dengue vaccine that could be used in dengue endemic countries to help prevent the disease.
It must be emphasized, however, that vaccines alone will not likely do the job. Rather, they should be used in combination with mosquito control, antiviral drugs and other new tools as part of integrated programs to effectively control dengue. In this context, PDC will continue working with its partners to promote the integration of innovative approaches for dengue prevention and control.