A helicopter races to deliver medical supplies, a team of doctors rushes to the nearest hotspot, a cargo plane airlifts laboratory equipment to a treatment center. These real-life scenarios from Operation Western Area Surge depict the level of speed, coordination, and planning that was ultimately required by the United Nations, its member states, and its partners to stop the Ebola outbreak of 2014-2016, which claimed 11,000 lives across the most-affected countries of Guinea, Sierra Leone, and Liberia.

The importance of quick reaction, operational flexibility, and an ability to work together across disciplines to tackle complex emergencies is a key message of our new International Peace Institute report, The Mission to Stop Ebola: Lessons for UN Crisis Response, in which we evaluate the UN Mission for Ebola Emergency Response (UNMEER). As the UN’s first-ever emergency health mission, UNMEER represented a groundbreaking experiment in international cooperation. Although this Ebola crisis is past, UNMEER’s experience continues to offer relevant insights for how the UN system can better respond to rapidly developing, multidimensional crises.

Given the intense scrutiny directed at the World Health Organization (WHO) post-crisis, some observers have overlooked UNMEER’s participation in the broader response. UN Secretary-General Ban Ki-Moon established UNMEER on September 19, 2014, with a mandate to lead and coordinate the activities of UN agencies working on the ground in order to stop the outbreak. By then the outbreak had outpaced the capacity of frontline responders to contain it, and there were reports of food shortages, school and hospital closings, and restrictive quarantines across the affected countries. WHO, in particular, lacked the resources and operational capacity to coordinate a large-scale response. A broader coordination effort was needed. On August 29, 2014, the presidents of the most-affected countries jointly called on the UN to take the lead.

However, no blueprint existed for how to address a multidimensional health emergency. There was no precedent to go on. What was needed, and ultimately adopted in UNMEER, was an integrated, whole-of-system response that could scale up and focus the efforts of WHO and other UN agencies behind a unified strategy.

As a result, the mission saw a number of key innovations. Unlike peacekeeping missions, which are based in-country, UNMEER adopted a regional office with headquarters in Ghana. This decision was made primarily due to safety concerns given projected estimates of the virus’s spread, as well as the imposition of travel bans to the affected countries. Since contagions do not respect borders, this regional perspective improved cross-border coordination, information sharing, and monitoring of viral transmission, but it did come with a cost. Many felt the mission was too far removed from the theater of operation in the affected countries. It’s possible that, given the right conditions, such a regional model could be beneficial if applied to other contexts.

Most importantly, UNMEER’s integrated approach is a case study in the UN’s potential to work toward greater integration and to deliver across its institutional divisions, or silos. Implementation saw both progress and pitfalls. Our research suggests that the most effective counter-measures drew upon the full range of UN tools and implementing partners based on the principle of comparative advantage.

For instance, under UNMEER’s direction and leadership, WHO provided technical expertise (e.g., training of healthcare workers), the World Food Programme provided logistics support (e.g., building Ebola treatment units), and other UN agencies filled vital roles based on their respective mandates and expertise. In another example of innovation, the mission contained embedded medical capacity, with WHO leading on health issues such as case finding, contact tracing, and laboratory services.

However, integration did not come seamlessly. The mission failed early on to adjust for differences in organizational culture, especially between peacekeepers and humanitarians. The mission’s centralized command structure in its start-up phase—modeled loosely on a peacekeeping framework and designed to facilitate its rapid rollout and delivery of vehicles, supplies, and personnel to the region—was viewed as inimical to many in the humanitarian community accustomed to a more horizontal management style. This was a source of friction when attempting to coordinate diverse response partners, and it also led to the exclusion of many stakeholders from initial consultations.

A key lesson in this regard is that providing UN missions with the ability to adapt their leadership, management style, and operations to fast-changing circumstances will be a critical component of successful emergency responses. This flexibility was on display in the process of decentralization that occurred within the mission once it reached full operating capacity in December 2014, which remedied some of the earlier challenges associated with its overly top-down launch.

This new posture also helped it to keep up with sudden shifts in transmission of the virus, which occurred around this time. In all, UNMEER underwent three distinct stages as part of a sequenced approach until its closing in July 2015—nimble by UN standards.

The fact that UNMEER achieved most of its targets—such as over 70% isolation and treatment of Ebola victims by December 1, 2014—may be viewed as one measure of its success, although it’s difficult to isolate its particular impact from those of myriad other actors on the ground, such as international NGOs and foreign military deployments. Among its most important contributions was that its high-profile launch at the UN Security Council and UN General Assembly helped to catalyze global political support and precipitate an influx of donor contributions. The mission received $5.1 billion in donations for the Ebola response by January 2015, compared to $155 million by September 2014.

Some have criticized UNMEER as an unnecessary stopgap that bypassed both WHO and pre-existing humanitarian crisis response structures. Nevertheless, UNMEER provides an example of how, during a rapidly developing and complex crisis, the UN, with member state support, can provide a whole-of-system response through coordination, partnerships, and the creative use of existing tools.

This will certainly not be the last time the entire UN system is called upon to mount a response to a fast-evolving emergency. Learning the lessons from UNMEER’s experience, including the importance of speed, coordination, flexibility, and partnerships, could save thousands of lives when the inevitable next crisis erupts.