Using drones to deliver vaccines in low- and middle-income countries may save money and improve vaccination rates, according to new research from the Johns Hopkins Bloomberg School of Public Health and the Pittsburgh Supercomputing Center.

The cost savings would come from drones being able to deliver vaccines more quickly and cheaply than land-based methods limited by road conditions and the need for costly fuel and maintenance, the researchers note in their study, published in the journal Vaccine.

“You make all these vaccines but they’re of no value if we don’t get them to the people who need them,” said senior author Bruce Y. Lee, MD, MBA, an associate professor at the Bloomberg School. “So there is an urgent need to find new, cost-effective ways to do this.”

In low- and middle-income countries, there are many challenges faced by immunization programs, which provide childhood vaccines such as hepatitis B, tetanus, measles, and rotavirus, and will be utilized in the future as vaccines for dengue, malaria, and Zika are developed and brought to market. After entering a country, vaccine vials typically travel by road through two to four storage locations before arriving at clinics where health workers administer doses to patients. Most vaccines need to remain refrigerated until they are used or they will spoil. Non-vaccine costs of routine immunizations are expected to rise by 80 percent between 2010 and 2020, with more than one-third of costs attributable to supply chain logistics. Supply chain inefficiencies can mean that many vaccines don’t even reach the people who need them.

Meanwhile, unmanned drones have proliferated in recent years because they can traverse difficult terrain, reduce labor costs and replace fleets of vehicles. They have been used for surveillance and in humanitarian aid delivery and are now being developed to transport medical samples and supplies, though previously little has been known whether this is a cost-effective use of the new technology.

For their study, Lee and his colleagues created a HERMES computer model to simulate a traditional land-based transportation system—a combination of trucks, motorbikes, and public transit—and compared it with an unmanned drone system for delivering vaccines as part of an immunization program. They varied characteristics such as geography, population, road conditions and vaccine schedule in order to assess which conditions would most contribute to drones offering the biggest cost savings.

They found that using drones to get vaccines to vaccination locations could slightly improve vaccine availability while producing significant savings: eight cents for every dose administered, a 20 percent savings. The researchers noted that many countries currently cover fewer than 60 percent of the population using land-based approaches.

“In many locations, vehicles that transport vaccines aren’t always available or reliable,” Lee said. “Assuming that drones are reliable, are capable of making the necessary trips, and have properly trained operators, they could be a less expensive means of transporting vaccines, especially in remote areas.”

Real-world testing must still be done to make certain that drones are a viable way to transport vaccines. And many obstacles may exist. Regulatory issues could limit their ability, maintaining and operating the equipment would require specialized tools and skills, and greater coordination would be needed between those shipping and those receiving the vaccines.

Drones are currently being tested for medical supply deliveries in rural Virginia, Bhutan and Papua New Guinea. UNICEF is testing the feasibility of using them to transport lab samples in Malawi. In Tanzania, there are efforts afoot to transport blood and essential medications.