At New Tafo Hospital, health care workers watch the sky, listening for a distinct buzzing noise they have grown used to in the past month. In seconds, a small drone comes into view and quickly drops a package before it returns to its base.

Ghana's drone service, launched in April, makes on-demand emergency deliveries of 148 different vaccines, blood products and lifesaving medications to health facilities in the country, 24 hours a day.

New Tafo, a government hospital about two hours north of the Ghanaian capital, Accra, was the first hospital to use the service, brought to Ghana by Silicon Valley company Zipline. Medical superintendent Kobena Wriedu said the hospital had received at least 25 drone deliveries in the past month, with a handful coming in emergency situations. The service is much faster than deliveries made by road, especially in Ghana, were road networks are poor.

Critical supply source

"There was this child who was on my ward who was virtually O Rh negative," a blood type that's difficult to get, Wriedu said. "We had to fall on Zipline. They were able to deliver it. … Sometimes, we need fresh frozen plasma for bleeding cases that we encounter, and the delivery is done in a very short time to save lives. So, many lives have been saved within the period of the one month that the medical drone service was launched in Ghana."

The products come from the country's first Zipline drone center at Omenako, which is about 40 minutes by pothole-riddled road to the hospital — or 12 minutes by drone. By the end of the year, an additional three centers are set to be opened across Ghana. Combined, they will provide deliveries to 2,000 health facilities serving 12 million people, making up to 600 delivery flights a day on behalf of the Ghanaian government, under a contract worth $12.5 million over four years.

Taking orders, preparing flights

The center in Omenako where the drones come from has a cold storage facility for the blood and medicines to be stored. Workers watch the screens as orders come through and quickly fill the orders and assemble and launch the drones. They get the orders from health care workers like George Appiah Boadu at the New Tafo Hospital, who places them by text message. For him, access to blood products has been particularly useful.

"We have pregnant women who also come in," Boadu said. "For instance, if we have an ectopic case and for this patient the only option for us is to get to the [operating] theater … if you don't have blood available, you risk losing her life." So the drone technology has been a lifesaver, he said.