Drugmakers have speculated about delivering temperature-sensitive vaccines and drugs to remote locations using drones. Now, Merck & Co. is testing the method. 

Merck initiated the idea, and a collection of players coordinated by humanitarian aid organization Direct Relief have now moved to proof-of-concept missions. They developed and flew a drone with a temperature-controlled payload over the waters around the Bahamas. 

"This successful pilot demonstrates the potential of innovative unmanned aerial vehicles technology to aid in delivery of temperature-dependent medicines and vaccines to people who critically need them," Craig Kennedy, Merck's senior vice president of supply chain, said in a statement. 

Drone maker Volans-i built and operated the all-electric drones, while packaging expert Softbox developed the temperature-controlled payload box. Merck provided supply chain consulting.  

The unmanned aerial vehicle flew over open water between the islands of the Bahamas and out of sight of the operator. The cold-chain delivery technology on the drone permitted precise temperature control to minus 70 degrees Celsius, a temperature required for storing and transporting some vaccines and drugs. Cloud-based technology from AT&T allowed continuous temperature tracking and real-time data collection and analysis during the flight.

Vaccine makers have long been working on how to get heat-sensitive vaccines to remote areas before they spoil. Progress has been made into making some of them so they can be moved at ambient temperatures, but that cannot always be achieved. 

Merck has a lot of experience with this. Its experimental Ebola vaccine, for example, is currently being used in an Ebola outbreak that started in remote locations in the Democratic Republic of Congo. 

The Bahamas flight was the fourth pilot effort, and testing will next be taken to Africa and Latin America. The group acknowledged that while the technology is promising, its viability in the real-world will depend on many factors, not the least of which are "evolving regulatory challenges." 

Still, the partners consider it an important step forward, particularly for the most vulnerable people and parts of the world.  

"Experience and research consistently show that those most at risk of health crisis in disasters live in communities which are likely to be cut off from essential health care due to disruption of transportation and communications," said Andrew Schroeder, analytics guru for Direct Relief. "Drone delivery is one of the most promising answers to this problem."