PARIS — Sanofi’s experimental vaccine against dengue protected children with all four types of the mosquito-borne illness in a clinical test, a stronger result than shown in a smaller study this year.
In a trial of almost 21,000 children in Latin America and the Caribbean, the shot reduced the risk of infection by 60.8 percent, the Paris-based company said in a statement Wednesday. The vaccine also led to an 80.3 percent drop in the risk of hospitalizations.
The results are validation of Sanofi’s two-decade effort to develop a vaccine for the debilitating infection, which is a growing problem in developing as well as developed countries. An outbreak in Tokyo has led to 34 cases, the Health Ministry said this week.
“For the first time ever, after 20 years of research and industrial commitment, dengue is set to become a vaccine-preventable disease,” said Olivier Charmeil, president of the French drugmaker’s Sanofi Pasteur vaccine unit.
About half the world’s population lives in countries threatened by dengue, the World Health Organization estimates. Of 390 million infections a year, about 96 million people are sickened to some degree, according to research published last year.
In a trial involving more than 10,000 children in Southeast Asia, the vaccine reduced the risk of infection by 56.5 percent, according to results published in July, though the inoculation was less effective among the youngest children who are most at risk, and failed to protect against one of four viruses that cause it.
There’s no approved treatment for dengue, which causes flu-like illness that can develop into potentially fatal complications including bleeding gums, vomiting, rapid breathing and severe abdominal pain.
Sanofi plans to publish full results from the Latin American trial in a scientific journal, and will present them at the American Society of Tropical Medicine and Hygiene conference in November. The Latin American and Southeast Asian studies are part of the third and final phase of clinical trials generally needed for regulatory approval.
Sanofi didn’t say when it will submit the shot for approval. The trial results will be submitted to authorities in countries where dengue is a public-health priority, the company said.
The vaccine may have peak sales of $1.2 billion by 2025, Peter Verdult, an analyst at Citigroup, said in a report Wednesday.
Takeda Pharmaceutical of Osaka, Japan, is also developing a dengue vaccine, as are Merck & Co. and the U.S. National Institutes of Health.