CHICAGO/LONDON: When French drugmaker Sanofi published the results of clinical trials of children given its dengue vaccine two years ago, the overall findings were that it protected against the world’s biggest and fastest growing mosquito-borne disease.
But the trial also showed that in the third year after receiving the Dengvaxia inoculation, younger children were more likely to end up in hospital with a severe case of dengue than those who didn’t get the vaccine.
The study’s authors cited two main possibilities: the children had immature immune systems that made the vaccine less protective, or the vaccine itself made them more susceptible to severe disease if they had never had dengue and later became infected.
More than two years later, it turns out the latter was the primary factor – a revelation at the end of last month that has triggered alarm among hundreds of thousands of anxious parents in the Philippines, where the vaccine has been given to over 830,000 children.
It has also torpedoed initial expectations by analysts and the company that Dengvaxia, the first dengue vaccine to be developed, might become a $1 billion-a-year blockbuster product. Sanofi says it will take a charge of around 100 million euros ($118 million) for the fourth quarter.
But the trial also showed that in the third year after receiving the Dengvaxia inoculation, younger children were more likely to end up in hospital with a severe case of dengue than those who didn’t get the vaccine.
More than two years later, it turns out the latter was the primary factor – a revelation at the end of last month that has triggered alarm among hundreds of thousands of anxious parents in the Philippines, where the vaccine has been given to over 830,000 children.
It has also torpedoed initial expectations by analysts and the company that Dengvaxia, the first dengue vaccine to be developed, might become a $1 billion-a-year blockbuster product. Sanofi says it will take a charge of around 100 million euros ($118 million) for the fourth quarter.
