Children in the remote South Pacific island nation of Vanuatu have received the first vaccines delivered commercially by drone. The drone delivery covered almost 25 miles of rainforests and rugged mountainous terrain.

The delivery brought potentially life-saving vaccines to 13 children and five pregnant women in Cook's Bay, a small, scattered community on the island that does not have a health center or electricity and is only accessible by foot or small local boats.

Currently 1 in 5 of Vanuatu's children do not receive their recommended shots, U.N. health officials said. UNICEF says drone technology could be a game-changer for health in remote corners of the world.

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"Today's small flight by drone is a big leap for global health," said Henrietta H. Fore, UNICEF's executive director. "With the world still struggling to immunize the hardest to reach children, drone technologies can be a game changer for bridging that last mile to reach every child."

Long-term, Vanuatu's government is interested in integrating drone delivery of vaccines into their national immunization program and using drones more widely to distribute health supplies. Data from this test program will also be used to inform other countries how drones can be used commercially in similar settings around the world.

"Today's first-of-a-kind vaccine delivery has enormous potential not only for Vanuatu, but also for the thousands of children who are missing out on vaccines across the world," Fore said. "This is innovation at its best, and shows how we can unlock the potential of the private sector for the greater good of the world's children."