Vaccine trials involve 31,000

My Paper caught up with Dr Joselito del Mundo Sta. Ana, senior director and regional head for dengue vaccines at Sanofi Pasteur in Asia-Pacific and Japan, on his firm's new vaccine, which could protect against all four types of the dengue virus.

Any updates on the dengue vaccine?

Large-scale phase-three clinical studies with 31,000 children and adolescents are ongoing in Mexico, Colombia, Honduras, Puerto Rico and Brazil; and in the Philippines, Vietnam, Malaysia, Indonesia and Thailand.

These studies follow the highest standards from the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use.

The studies are designed to assess the efficacy of the candidate vaccine.

When might the vaccine be ready for use?

It is expected that, by next year or 2015, the phase-three clinical studies will be completed, and we will be able to submit the outcome to regulators in each country for registration.

Sanofi Pasteur's objective with its dengue vaccine is to have a significant impact on public health in endemic countries. But the decision to use the vaccine will be made by the countries themselves, and not by Sanofi Pasteur.

Their decision will depend on many factors, including the disease burden, the time taken to license the vaccine and their ability to implement large vaccination campaigns.

Are there any other dengue vaccines?

Several groups are in pre-clinical or early development of potential dengue vaccines.

Sanofi Pasteur's candidate vaccine is the world's first tetravalent dengue vaccine to reach the final stage of clinical development.

Why is it so difficult to make a dengue vaccine effective against all four types of dengue virus?

There are four dengue (virus types) and a vaccine has to be effective against all four types.

There is (also) no animal model (that can be used to study) a dengue vaccine. Hence, there are no shortcuts in terms of development, and there is a need for large-scale human effectiveness and efficacy studies, which are both expensive and time-consuming.

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