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.

The price of the vaccine and the timing of the first innoculations haven't yet been announced; the three countries are still negotiation with the pharmaceutical company behind the drug, Sanofi, Scientific American reports. But it's seems likely that the drug will start being administered in those countries in the coming year. In addition, the World Health Organization plans to examine the drug in April 2016; they will release recommendations for its use soon thereafter. It's unclear if or when the drug might be approved in the US. In Hawaii, health officials have recorded over 100 cases of dengue since September — 29 of those cases occurred in children under the age of 18.