A new vaccine for the dengue virus is taking a potentially risky road to prevent the mosquito-borne disease that infects nearly 400 million people each year.

Takeda Pharmaceutical Co. plans to seek approval for the experimental vaccine first in countries where the virus is endemic, rather than starting with the United States or Europe, whose rigorous reviews are often used as a benchmark worldwide, company executives said.

The strategy mirrors one used by Sanofi SA, which licensed the world's first dengue vaccine, Dengvaxia, in endemic markets in 2015 before attempting to get approval from Western regulators, and forecast up to $1 billion in annual sales.