Zipline — Desk-Based Scoping of Drones to Increase Vaccination Coverage (December 2024)

Note: This page summarizes the rationale behind a GiveWell grant to Zipline. Zipline staff reviewed this page prior to publication.

Published: March 2025

Background

Zipline is a for-profit company that specializes in on-demand, drone-based delivery of goods, including (but not limited to) medical supplies such as medicines, labwork, and vaccines. They began delivering blood in Rwanda in 2016, and since then have expanded their healthcare and commercial drone delivery solutions to Ghana, Nigeria, Côte d’Ivoire, and Kenya, as well as the United States and Japan.2 As of December 2024, they have provided aerial logistics services to more than 4,500 hospitals and health facilities. Their drone delivery platform enables cold chain integration for the transportation of temperature-sensitive products.3 This grant is the first partnership between GiveWell and Zipline.

As discussed in this blog post, we think that interventions that make vaccination easier and more accessible are promising, and we’re now exploring how to expand our work in this space.
Currently, we are focused on:4

• Vaccines delivered to children under-2.
• Layering of high-value interventions that can be delivered alongside vaccines.
• Locations with low vaccine coverage rates and high child mortality rates.
• Interventions that can increase vaccination rates by making takeup much easier, namely by bringing vaccines closer to where parents and infants are, or offsetting the costs through incentives.

We expect to fund scoping, piloting, and evaluation before scale-up for most program types. For some GiveWell-funded interventions, there is a clear-cut intervention (e.g. a commodity given out in a door-to-door campaign) that can be scaled up in very similar ways in different locations. Vaccination programs are more integrated into countries' health systems than campaigns, and our working hypothesis is that whether an intervention is successful and cost-effective likely depends on highly contextual factors.

To that end, we are having discussions with several organizations that work with health systems in countries with high rates of vaccine-preventable disease about generating ideas for and testing approaches to increasing vaccination rates.

What we think this grant will do

This grant will support a small team5 of Zipline staff during a six-month scoping period to develop one or more proposals to investigate whether drones can cost-effectively increase vaccine uptake. Zipline typically uses drones to deliver vaccines and other health commodities to hospitals and health facilities. In this grant, Zipline is particularly interested in exploring new drone-based vaccine delivery strategies including:

1. Distribution to health posts and other lower-complexity health facilities
2. Direct delivery to community health workers
3. Establishment of new access points for vaccination
4. Bundling the delivery of vaccines with other essential health interventions

Zipline’s proposed activities6 during this grant are included below, taken directly from their proposal:

Why we made this grant

This is a small scoping grant to Zipline to develop some ideas for ways that drones can solve bottlenecks in vaccine delivery, especially in particularly hard-to-reach areas. See the Background section above for more details on how this engagement fits in with GiveWell’s work on vaccination more broadly.

We think this grant is worthwhile because:

• GiveWell is interested in raising vaccine coverage among the lowest dose children, some of whom live in remote areas that are difficult to reach through traditional routine immunization services delivered at primary healthcare facilities.
• Intuitively, we think that drones could be an effective strategy to physically bring vaccines closer to communities and circumvent barriers like poor infrastructure, difficult terrain, cold chain issues, rainy seasons, and insecurity.
• An evidence assessment of drones for health that GiveWell conducted internally in 2023 concluded that, to be cost-effective, drone-delivered care would need to operate in contexts with high prevalence of life-threatening conditions and low existing treatment coverage, where ‘last-mile’ delivery problems are a significant barrier to receiving care.7 This scoping grant to Zipline will test this hypothesis by targeting these specific areas to see if there’s potential for a cost-effective use of drones for vaccine delivery.
• Though this is our first engagement with Zipline, there are some early signals that we might be well-aligned as partners. Zipline’s proposal specifically calls out a few elements that are important to GiveWell: a) emphasis on cost-effectiveness8 , b) plans to establish an M&E framework early on for any potential pilots, and c) interest in evaluation and learning.9
• Sending vaccines via temperature-controlled drones could also improve adherence to cold chain requirements, plausibly leading to improvements in efficacy.

Our main reservations

Scoping grants are by nature very experimental, and at this point we have substantial uncertainty about whether we will be able to source any fundable opportunities at the end of this scoping phase for a few reasons:

• Compared to other organizations working in immunizations, Zipline has a relatively narrow focus within the vaccine supply chain and also a limited geographic reach. This will limit the possibilities for follow-on pilot and evaluation work coming out of this scoping period.
• Evidence on cost-effectiveness of drones for vaccine delivery is limited10 , and we have not modeled the cost-effectiveness of the types of programs that Zipline plans to consider, nor the value of information for this scoping grant. An internal review conducted in 2023 focused on drones for health was generally skeptical about there being many opportunities in this area that would meet GiveWell’s bar, although this scoping grant will focus on the most promising scenario (remote areas with high rates of vaccine-preventable diseases and low vaccination coverage rates).
• There is limited evidence11 on whether the use of aerial logistics actually leads to increased vaccination coverage rates. If this grant leads to additional follow-on work, we hope to help fill this evidence gap.

Plans for follow up

• Zipline and GiveWell will have one midpoint check-in and one check-in at the conclusion of the six-month period
• At the end of six months, Zipline will share a written proposal describing their top idea(s) for a potential pilot and evaluation

Internal forecasts

For this grant, we are recording the following forecasts:

Our process

• GiveWell and Zipline had several conversations about Zipline’s experience and GiveWell’s vaccines strategy
• Zipline sent us a proposal

Relationship disclosures

None

Sources

• 1A study from 2023 (conducted by Zipline staff) found that aerial logistics provided by Zipline contributed to higher vaccine coverage rates in Ghana. "Facilities served by aerial logistics reported significant reductions in the duration of vaccine stockouts (30 %, p-value < 0.05), as well as in the frequency of missed opportunities for vaccination (44 %, p-value < 0.05)... Significant differences in vaccination coverage were found for most vaccines, in a range between 13.1 and 37.5 percentage points in vaccination coverage for served districts." (p. 1)
  • However, the quasi-experimental portion of the study did not have a pure control group (instead compared high-intensity and low-intensity implementation areas), and selection between the high-intensity and low-intensity implementation groups does not appear to have been randomized. Data on vaccine coverage was from administrative data, which we generally put less weight on than survey results, due to concerns about completeness and accuracy. The study also lacked some detail on the difference-in-differences design and the measurement strategies for the key outcomes.

• 2

  Zipline, About

• 3

  Zipline, Solutions - Public Health

  • GiveWell has not conducted in-depth research into Zipline's cold chain capabilities

• 4

  The focus areas mentioned here are not completely aligned with the blog post about our vaccines strategy that was published in September 2024; rather this list reflects an updated set of priority areas for our vaccines team, with a focus on those most relevant to this grant.

• 5

  This team includes an Impact Lead, a Health Economist, Country Managers, and other support staff.

• 6

  The proposed budget of $54,620 will cover:

  • Staffing: $40,020
  • Travel for stakeholder engagement: $12,000
  • Fees for data and tool licensing, access to research articles: $2,600
  • $40,020 + $12,000 + $2,600 = $54,620

• 7

  This assessment was prepared internally as an initial review of the potential of drones for health as an intervention area for potential GiveWell grantmaking.

• 8

  Cost-effectiveness is something that Zipline pays close attention to and they recently completed their own modelling study of their last-mile delivery platform in the Western North Region of Ghana. "Our analysis confirms that at-scale aerial logistics for vaccine delivery is highly cost-effective, providing significant health benefits at a cost substantially lower than the WTP threshold from both governmental and societal perspectives." (p. 7)

  • We have reviewed this study at a shallow level and were unable to quickly assess how key parameters like program costs and the impact of the program on vaccination uptake and disease were being estimated. GiveWell would independently estimate cost-effectiveness to assess the promisingness of specific programs, but we have not done an in-depth modeling of cost-effectiveness for this grant or the potential follow-on work. For more on how GiveWell uses cost-effectiveness in our grantmaking see this page.

• 9

  To our knowledge, Zipline has funded two impact evaluations but has not done an RCT yet. Impact evaluation brief from IDinsight here; Impact assessment done internally and published in a peer-reviewed journal is here.

• 10

  An internal evidence assessment from 2023 on “drones for health” concluded that this intervention is not promising and unlikely to reach our cost-effectiveness bar. There are some important differences between this assessment and the work that Zipline will do as part of this grant, but some of these concerns/limitations remain.

• 11

  Impact assessment done internally by Zipline (here) shows that drone-based delivery contributed to increases in vaccine coverage in Ghana. "Facilities served by aerial logistics reported significant reductions in the duration of vaccine stockouts (30 %, p-value < 0.05), as well as in the frequency of missed opportunities for vaccination (44 %, p-value < 0.05)...Significant differences in vaccination coverage were found for most vaccines, in a range between 13.1 and 37.5 percentage points in vaccination coverage for served districts." (p. 1)

  • However, the quasi-experimental portion of the study did not have a pure control group (instead compared high-intensity and low-intensity implementation areas), and selection between the high-intensity and low-intensity implementation groups does not appear to have been randomized. Data on vaccine coverage was from administrative data, which we generally put less weight on than survey results, due to concerns about completeness and accuracy. The study also lacked some detail on the difference-in-differences design and the measurement strategies for the key outcomes.