But the tenth and current outbreak is different. While the previous ones took place in the Congo’s northern and western regions, this one had the grave misfortune to spark up in the eastern provinces of North Kivu and Ituri. These regions abut Rwanda and Uganda, and are active war zones full of displaced refugees.

To control Ebola, health workers need to find infected people, track whomever they had contact with, deploy vaccines, and convince people to forgo deeply held burial practices that put them in touch with the virus-ridden bodily fluids of their dead loved ones. All of that becomes infinitely harder in regions plagued by armed conflict, where people are distrustful of health workers.

Those workers have come under attack themselves. Hospitals, treatment centers, and operational facilities have been pelted with stones, set on fire, and stormed by armed assailants. Volunteers have been attacked while trying to bury Ebola victims. Two Ebola workers were murdered in their homes. Small wonder that the outbreak has proved unusually hard to contain.

Read: The next plague is coming. Is America ready?

The WHO hopes that the PHEIC declaration will act as a rallying cry. “I urge the international community to step up and put its full support behind the Ebola response,” said Matshidiso Moeti, the WHO regional director for Africa, on Twitter. The PHEIC declaration is “an opportunity to ensure the international community does not turn its gaze, but rallies to support DRC and Africa in the fight to end the Ebola outbreak.”

But for many parties involved in the outbreak response, the PHEIC decision came bafflingly late. “Finally after 1600 deaths?” Marc Yambayamba from the Kinshasa School of Public Health said on Twitter. “Almost all international legal and policy experts agree that the conditions for declaring a public health emergency of international concern were met long ago,” added Rebecca Katz, who directs Georgetown University’s Center for Global Health Science and Security, in a statement.

The PHEIC label was created in 2009, as part of international regulations to which the WHO’s member states must adhere. It’s an alarm bell, to be rung when the world must collectively mobilize against “an extraordinary event” that involves “the international spread of disease” and “may require immediate international action.” Until now, only four events have met that criteria: the swine-flu pandemic of 2009, the resurgence of polio in 2014, the West African Ebola outbreak, and the Zika epidemic of 2016.

The WHO had previously convened three emergency meetings to discuss whether the current Congolese outbreak also warranted PHEIC status. Thrice, the committee said that it didn’t, arguing that a declaration would do little to improve matters. For example, a PHEIC allows the WHO to compel the affected countries to disclose information that would be relevant to responders—but the Congo has been very transparent. A declaration also carries risks, as other countries might react by imposing trade and travel bans that would paradoxically stanch the flow of support and make the outbreak even harder to stop.