The World Health Organization last week drew global attention to a nearly year-old outbreak of Ebola in the Democratic Republic of the Congo (DRC), calling it a “public health emergency of international concern.” The designation signals a public health risk to other countries and indicates that a coordinated international response might be needed. The agency based its decision in part on the first confirmed case of Ebola in Goma, a DRC city of nearly two million people on the country’s eastern border with Rwanda. That shift raises the risk that the disease could spread internationally.

This Ebola outbreak is the second worst on record, with roughly 2,500 documented cases of people with Ebola virus disease and about 1,700 deaths so far. The situation has been compounded by deadly violence against health care workers and mistrust of outside medical authorities. In recommending the emergency declaration, a WHO committee emphasized “disappointment about delays in funding,” as well as the need to protect people’s livelihoods by “keeping transport routes and borders open.” A coordinated response to the outbreak is under way, including distribution of a new vaccine, but the committee says more work is needed to help people and communities affected by Ebola.

Chandy John, president of the American Society of Tropical Medicine and Hygiene, is an infectious disease expert who has not studied Ebola specifically, but has studied outbreaks of other infectious diseases, including malaria. Scientific American spoke with him about what the emergency declaration aims to accomplish, as well as the biggest challenges in turning the tide against the current outbreak.

[An edited excerpt of the conversation follows.]

What is the WHO hoping to achieve with this emergency declaration about the outbreak?

There has been a coordinated international response, mostly organized by the WHO, but they’ve noticed that despite numerous recommendations for increased resources, the global community hasn’t contributed what they feel is necessary for this outbreak. An announcement like this puts it front and center that there is a need for a coordinated international response. And it’s a crisis, so both the coordination and the balance of resources that are needed are higher than for usual public health problems. And hopefully, that means that more resources will then be devoted to it.

When you say resources, are we talking about money, staff, vaccines or all of the above?

Money, for sure, but their real problem is with security and with health workers being killed. So, we need countries contributing to a United Nations presence there that could provide security to health workers that are at risk, as well as the ability to deploy more vaccine, the ability to make more vaccine, and funds for local health workers. So yes, it’s all of the above.

Do you think this type of declaration by the WHO will have an impact on the outbreak in terms of those measures?

Yeah, I think that everybody believes it will. There have been calls for this from a number of groups prior to this. This designation has not been used very often. But a lot of groups felt that we really needed to move ahead to this, partially because people feel that once the outbreak is declared as a PHEIC [Public Health Emergency of International Concern], countries are more likely to step up on contributing resources. So I hope that happens.

Can you talk about what we might do to stem the violence against health care workers and whether this declaration could help?

The groups or forces on the ground—it doesn’t necessarily need to be armed forces—can provide security to health workers so they don’t feel that their lives are at risk when they go into these communities. That’s one thing. But another is getting groups to talk about what’s happening there and understanding the social science of the situation: what the fears are, why people are doing this.

Is there mistrust of both the public health response and of the vaccine being administered?

There’s suspicion of health workers, and in some areas, there is suspicion of vaccines. But by and large, as the vaccine has been given out, it has mostly been accepted. So now, it’s more a question of supply than fear of vaccination. Merck, which makes the vaccine, is committed to doubling the supply by 2020. But it still may not be enough for all who need it. There is also a second vaccine by Johnson & Johnson that they would like to study, but so far that hasn’t been approved for study in the DRC. It’s new, and it doesn’t have the same track record as the other one, so they would be studying the vaccine and its efficacy. But in the long term, if we could use it and see that if it was efficacious, that might be part of the solution. The amount of the current vaccine that can be supplied is in the hundreds of thousands of doses. And that will work for certain vaccination strategies, but for broader vaccination strategies, you might need more than that. Because the supply has been relatively constrained, they’ve been using an adjusted smaller dose that seems to still give an adequate response. So, that’s one of the ways in which they’ve been kind of extending the vaccine.

Can you say more about the tipping point that prompted the emergency declaration?

There’s one particular area which is the epicenter of the outbreak—46 percent of cases in the last three weeks have been reported from there and it seems to be continuing there. The fact that they haven’t been able to get it under control in that area was a factor. But I think the person who traveled to Goma, and then was in Goma and ill, is kind of front and center of the WHO’s report on the emergency declaration. That would seem to be the biggest thing that may have pushed towards this.

How concerned should we be about Ebola outbreaks spreading internationally?

During the previous outbreak, cases were transmitted internationally and caused a panic. In the U.S., it cost in the billions of dollars for a very small number of cases in 2014. It’s potentially a plane ride away. And I don’t mean that in a scaremongering way, but just to say that diseases now know no borders. What’s happening in the DRC matters to the U.S. for the health of our citizenry. And that’s a reason why we really need to dedicate U.S. dollars to this effort.

Are there other steps that should be taken to stem the outbreak?

I think a lot of it is extension of what’s being done already and doing it in additional areas. Part of it is investigating what’s happening in the communities, how people understand the disease, how people understand the role of health care workers, the screening at cross-border areas. I also think that there are things on-site that need to be investigated, such as how to prevent infections that are transmitted in hospitals, because people go to the hospital and perceive that they just die there. That’s part of why people are suspicious of health care workers—they’re typically from outside, they’re coming in and working at these places where people go to die. Also, are there ways that the extremely restricting protective gear can be altered, and yet leave health care workers safe? Because it’s basically like being in a spacesuit in extremely hot weather on land—it’s very difficult to stay in that protective gear for a long period of time.