By some measures, the world has at last reached a tipping point in the decades-long fight against Ebola, one of the most treacherous infectious diseases known to mankind. An experimental vaccine is believed to be effective, and this week came word that that one and perhaps even two drugs appear to significantly reduce the fatality rate among treated patients.
But to declare victory against the virus would be to overlook fundamental truths about outbreaks. In some circumstances at least — and the current long-running outbreak is one — Ebola will not be vanquished by vaccines and drugs alone.
“I think the news today is fantastic. It gives us a tool in our toolbox against Ebola. But it doesn’t in itself stop Ebola,” Dr. Mike Ryan, who runs the World Health Organization’s health emergencies program, told reporters earlier this week, sounding somewhat subdued, as health officials announced that for the first time a clinical trial had shown an Ebola treatment was helping people survive the virus.
He added: “What will stop Ebola is … good surveillance, good infection prevention and control, good community engagement, excellent vaccination and the use of these therapeutics in the most effective way possible, in safe and humane Ebola treatment units. It’s not one answer. It’s many things.”
Time and again over the more than 40 years since the first observed Ebola outbreak, basic principles of infectious disease control have stopped spread of the virus.
Find the people who are infected and care for them in isolation so they cannot infect others. Identify others who might have been infected and monitor their health. Rapidly isolate any of those contacts if they get sick. Ensure that those who die are buried safely, without funeral rites that might bring people into contact with corpses that are teeming with viruses.
And hope for the occasional measure of good fortune. A number of Ebola outbreaks have taken place in remote setting where there simply were not lots of people for the virus to infect.
There’s no such good luck in the current outbreak in Democratic Republic of the Congo. Not only are there plenty of people — the region is home to more than 8 million clustered in cities of tens, even hundreds of thousands of people — there is also conflict and armed gangs and whole villages where health workers cannot safely travel. And the inability to travel freely makes it difficult to deploy the fundamental tools of infectious disease response.
To date, nearly 2,850 people have been infected with the virus in this outbreak. Nearly 1,900 have died.
The challenging conditions on the ground have meant the outbreak response has never had a complete picture, in real time, of where the virus is spreading. Even as health officials have sought to compile lists of contacts of Ebola cases, they have routinely come across people who were infected who never appeared on those lists. As a result, those patients were never offered the chance to be vaccinated.
People in the region, distrustful of their government and of outsiders, haven’t always cooperated with the response; at times some actively work against it. Seven people working for the response have been killed, burial teams have been attacked, and treatment centers and roadside health checkpoints have been destroyed.
People in the region have also hidden their sick, caring for them in the community. It’s been estimated at least a third of cases have died at home, which helps the virus spread. Even those who agree to go to one of the specialized Ebola facilities that have been set up, the ones that offer the new drugs and the best chances for survival, often come too late to be saved.
Jeremy Konyndyk, who in late April led a three-person mission to DRC at the behest of the WHO to assess the outbreak response, explained that Ebola is fundamentally a behavioral disease. Its transmission is fueled by instincts that are hardwired into people, such as caring for loved ones who are sick. Stopping Ebola requires people to change those behaviors, to ignore those impulses.
“This is one of the really pernicious things about Ebola, is it is a disease that preys on very basic human instincts and human emotions,” said Konyndyk, a senior policy fellow at the Center for Global Development who also worked on the response to the 2014-2016 West African Ebola crisis while at the U.S. Agency for International Development. “Stopping the spread is not just a matter of curing the people who already have it. It’s a matter of preventing those who have it from spreading it to others through those risky behaviors.”
That means unless behaviors change, drugs and vaccines can only do so much, he said. “What’s clear is we should not be overconfident about the impact that medical countermeasures can have on their own,” Konyndyk said.
The experience with the experimental Ebola vaccine has made that clear. The WHO has said repeatedly that about 90% of people offered a chance to be vaccinated take it. But that means 10% do not. And many people who should be vaccinated never hit the radar of the vaccination teams; others who have been identified as contacts of cases flee before vaccine teams can find them.
The upshot: The vaccine, which has been shown to be highly effective, isn’t getting to enough of the people who have been in the virus’ path.
Similarly the existence of drugs to treat Ebola patients — this is only the second outbreak in which they have been available — hasn’t yet proved a strong enough lure for many who are sick. In this outbreak, like many before it, Ebola treatment centers have come to be seen as places from which only coffins emerge.
Dr. Jean-Jacques Muyembe, who now leads DRC’s response, is using every chance he has to try to turn that narrative around. “Ebola is not synonymous with death,” he said Tuesday as a mother and her young daughter were discharged from a treatment center at Goma after successful treatment. “Rather, Ebola is curable.”
Outbreak leaders hope this message will take root and people will come for care soon after they notice symptoms, when the drugs are most effective. If they do, that should help the response teams get a better grasp on where the virus is spreading, said Gary Kobinger, a Canadian scientist who led the team that developed ZMapp, another experimental Ebola drug. (That therapy, which had been the source of great hope during the West African Ebola epidemic, is not one of the two deemed to be most effective in the clinical trial wound up this week and will no longer be used in this outbreak.)
Kobinger, who has worked on many Ebola responses and was part of Konyndyk’s mission in April, was cautious about concluding, however, that the success of the clinical trial will have the effect Muyembe and others hope it will.
“If you don’t have the fundamental case finding and surveillance system, it may also be that there’s no impact of this and this outbreak keeps spiraling out of control,” said Kobinger, director of the Infectious Disease Research Center at Laval University in Quebec.
Dr. Heinz Feldmann, another old hand in Ebola responses, is hopeful the drugs will boost the effectiveness of the traditional response measures.
“We are in a wonderful situation now to finally offer a sick person — an Ebola sick person — something. I think this is really great,” said Feldmann, who led
the work to develop the Ebola vaccine currently in use and who heads the National Institute of Allergy and Infectious Diseases’ virology laboratory in Hamilton, Mont.
“This all is a package. If we now believe we can just drop our efforts that have been successful before in outbreak management, I think that would be a big mistake. We still need that part. … I think the vaccines, the treatments, and the normal outbreak response have to work together. And we’re going to have a real chance.”