Elsevier

Vaccine

Volume 34, Issue 34, 25 July 2016, Pages 4062-4067
Vaccine

The economic and operational value of using drones to transport vaccines

https://doi.org/10.1016/j.vaccine.2016.06.022Get rights and content

Highlights

  • Vaccine supply chains in low and middle income countries face numerous challenges.

  • Unmanned aerial vehicles (UAVs) are being developed for vaccine distribution.

  • HERMES-generated simulation modeling assessed UAV impact under various conditions.

  • UAVs raised vaccine availability and saved costs over traditional land transport.

  • With sufficient UAV utilization, cost savings were robust to sensitivity analyses.

Abstract

Background

Immunization programs in low and middle income countries (LMICs) face numerous challenges in getting life-saving vaccines to the people who need them. As unmanned aerial vehicle (UAV) technology has progressed in recent years, potential use cases for UAVs have proliferated due to their ability to traverse difficult terrains, reduce labor, and replace fleets of vehicles that require costly maintenance.

Methods

Using a HERMES-generated simulation model, we performed sensitivity analyses to assess the impact of using an unmanned aerial system (UAS) for routine vaccine distribution under a range of circumstances reflecting variations in geography, population, road conditions, and vaccine schedules. We also identified the UAV payload and UAS costs necessary for a UAS to be favorable over a traditional multi-tiered land transport system (TMLTS).

Results

Implementing the UAS in the baseline scenario improved vaccine availability (96% versus 94%) and produced logistics cost savings of $0.08 per dose administered as compared to the TMLTS. The UAS maintained cost savings in all sensitivity analyses, ranging from $0.05 to $0.21 per dose administered. The minimum UAV payloads necessary to achieve cost savings over the TMLTS, for the various vaccine schedules and UAS costs and lifetimes tested, were substantially smaller (up to 0.40 L) than the currently assumed UAV payload of 1.5 L. Similarly, the maximum UAS costs that could achieve savings over the TMLTS were greater than the currently assumed costs under realistic flight conditions.

Conclusion

Implementing a UAS could increase vaccine availability and decrease costs in a wide range of settings and circumstances if the drones are used frequently enough to overcome the capital costs of installing and maintaining the system. Our computational model showed that major drivers of costs savings from using UAS are road speed of traditional land vehicles, the number of people needing to be vaccinated, and the distance that needs to be traveled.

Introduction

Immunization programs in low and middle income countries (LMICs) face numerous challenges in getting life-saving vaccines to the people who need them. 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 [1]. Non-vaccine costs of routine immunization systems are expected to rise by 80% between 2010 and 2020, with more than one-third of these costs attributable to supply chain logistics [2]. Supply chain bottlenecks and inefficiencies can cause vaccines to spoil and valuable resources to be wasted before vaccines reach the people who need them, suggesting a need for innovative and lower cost methods for distribution. As non-military unmanned aerial vehicle (UAV) technology has advanced in recent years, interest in potential humanitarian and development use cases for UAVs have proliferated due to their ability to traverse difficult terrains, reduce labor, and replace fleets of vehicles. UAVs have already been successfully deployed for surveillance and aid delivery in humanitarian sectors and commercial systems are currently being developed to transport medical samples and supplies, including vaccines [3], [4], [5].

Despite this growing interest, limited evidence is available regarding the impact of UAVs for routine delivery of medical supplies. As with any new technology, the costs of purchasing, maintaining, and operating UAVs and their supporting launch/recovery and maintenance infrastructure – collectively called an unmanned aerial system (UAS) – may be prohibitive. The limited carrying capacity and required flight conditions of UAVs may also pose significant obstacles. Determining whether a UAS would be beneficial to an immunization program is difficult without a model to forecast supply chain performance and costs. We used simulation modeling to assess the impact of using a UAS for vaccine distribution under a range of circumstances and to identify the necessary conditions for a UAS to be favorable over traditional land-based transport.

Section snippets

HERMES models of Gaza province, Mozambique vaccine supply chain

Our team used our HERMES (Highly Extensible Resource for Modeling Event-driven Supply Chains) software platform, described in previous publications [6], [7], to develop a discrete-event simulation model of the World Health Organization (WHO) Expanded Program on Immunization (EPI) supply chain in Gaza, a province in southern Mozambique with a 2015 population of 1,416,810 [8]. This HERMES model includes virtual representations of each vaccine vial, facility, storage equipment, transport device,

Baseline scenario

In the baseline scenario, implementing the UAS improved vaccine availability (96% versus 94% for a 2% increase) and reduced costs ($0.33 (2015 USD) versus $0.41 per dose administered for cost savings of $0.08 per dose administered) as compared to the TMLTS. Vaccine availability improved due to the UAS relieving transport bottlenecks in several routes supplying health centers. These bottlenecks arose in the TMLTS where vaccine carriers lacked sufficient capacity to hold a one-month supply for

Discussion

In addition to improving supply chain performance, the UAS reduced the logistics cost per dose administered by approximately 20% in the baseline comparison. Savings in UAS transport, per diem, and labor costs offset the additional hub infrastructure costs, however, heterogeneity in cost savings among the individual hubs suggests a tailored approach is needed as hub infrastructure costs become prohibitive when insufficiently utilized. UAS cost savings remained robust to a set of sensitivity

Limitations

By definition, models are simplified representations and cannot incorporate all aspects of a system. The commercial UAS industry targeting the development sector is immature and limited data are available on operational costs at scale in environments like the one modeled. Our baseline scenario used currently publicly available UAS characteristics [4], [9], [10], [12]; however, to account for the range of possible UAS characteristics, we conducted extensive sensitivity analyses and aimed to find

Conclusion

Implementing a UAS could increase vaccine availability and decrease costs in a wide range of settings and circumstances if the drones are used frequently enough to overcome the capital costs of installing and maintaining the system. Our computational model showed that major drivers of cost savings from using the UAS are road speed of traditional land vehicles, the number of people needing to be vaccinated, and the distance that needs to be traveled. Modeling can help guide UAS development,

Acknowledgements

This work was supported by the Bill and Melinda Gates Foundation, the Agency for Healthcare Research and Quality (AHRQ) via grant R01HS023317, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Office of Behavioral and Social Sciences Research (OBSSR) and the Global Obesity Prevention Center (GOPC) via grant U54HD070725 and NICHD via U01HD086861. The funders had no role in the design and conduct of the study; collection, management, analysis, and

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