A baby on a small Pacific island has become the first person given a vaccine delivered by a commercial drone.
Unicef arranged for the drone to be flown some 40km (25 miles) across rugged mountains in Vanuatu that otherwise take hours to cross.
About 20% of children in Vanuatu don't receive important vaccinations because the supply is too difficult.
The UN children's organisation hopes that drone delivery will in future be of vital importance in remote areas.
"Today's small flight by drone is a big leap for global health," Unicef executive director Henrietta Fore said.
"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."
While drones have been used before to deliver medicine, Unicef says this was the first time globally that a country had contracted a commercial drone company to get vaccines to remote areas.
Two companies competed for the project on Vanuatu, and it was Australia's Swoop Aero that won the bid after successful trials earlier this month.
Its drone carried the vaccines in a styrofoam box with ice packs and a temperature logger to a remote village on the island of Erromango, from Dillon's Bay on the west of the island to Cook's Bay on the east.
The medicine was then used by local nurse Miriam Nampil to vaccinate 13 children and five pregnant women.
Without the drone, Cook's Bay is only accessible on foot or by boat - both those options take hours compared to the 25 minutes it took for the drone to reach the village.
Medical supplies also have to be kept at a cold temperature.
"It's extremely hard to carry ice boxes to keep the vaccines cool while walking across rivers, mountains, through the rain, across rocky ledges," Ms Nampil said.
"As the journey is often long and difficult, I can only go there once a month to vaccinate children. But now, with these drones, we can hope to reach many more children in the remotest areas of the island."