Every year, mosquito bites cause up to 400 million dengue infections, which in turn lead to about 22,000 deaths. Until recently, health officials had no way to prevent or even treat the disease, but that’s about to change. In the last month, three countries — Brazil, the Philippines, and Mexico — have approved the world’s first dengue vaccine for human use, according to Scientific American.
The dengue vaccine isn’t ideal. It only reduces people’s chances of developing dengue by 60 percent, and it’s not approved for children below the age of nine. Still, the drug is 95.5 percent protective against the most severe form of the disease, dengue hemorrhagic fever. Right now, there are 500,000 cases of DHF worldwide each year. So the drug could help reduce the number of dengue-related hospitalizations in those three countries.