Scientists battling the deadly Ebola virus are poised for a breakthrough in the new year after an experimental vaccine shot proved to be 100-percent effective during a trial in West Africa and received fast-track status from the Food and Drug Administration.
Among the 5,800-plus people who received the vaccine in 2015 in Guinea — one of three countries devastated by the epidemic that was only fully contained in 2016 — not one of them caught the disease 10 or more days after vaccination.
Yet there were 23 cases of Ebola among those who participated in the study but did not get vaccinated, according to newly published results in The Lancet, a prestigious medical journal.
“While these compelling results come too late for those who lost their lives during West Africa’s Ebola epidemic, they show that when the next Ebola outbreak hits, we will not be defenseless,” said Dr. Marie-Paule Kieny, assistant director-general for health systems and innovation for the World Health Organization.
Indeed the results, combined with emerging research on survivors and therapeutics for those who catch the disease, have scientists feeling like they’ve turned a corner against the deadly disease that’s largely fallen out of sight.
“I think the coming year will be positive for Ebola, even though there won’t be an outbreak of Ebola — we hope,” said Dr. Anthony Fauci, director of infectious diseases research at the National Institutes of Health.
Ebola killed more than 11,300 people in Guinea and neighboring Liberia and Sierra Leone from December 2013 to early 2016, making it by far the worst outbreak of the disease since scientists discovered the virus in 1976.
The epidemic attracted a massive — if belated — international response and induced global panic, with many countries banning or limiting travel from the hot zone.
It also set off a race for a vaccine, as global health officials strive to avoid a repeat.
Known in lab-speak as rVSV-ZEBOV, the vaccine used in Guinea was developed by the Public Health Agency of Canada and licensed to NewLink Genetics Corp., which collaborated with pharmaceutical giant Merck.
Merck expects to file for a license from the FDA by late 2017, after the vaccine was used on an emergency basis amid the West African outbreak. The FDA granted it “breakthrough therapy” status to open lines of communication with the company and expedite the vaccine’s development and review.
“Generally speaking, we are in the process of assembling the critical components required for licensure with national regulatory agencies and are looking to accelerate the process wherever we can/where possible,” Merck spokeswoman Pamela Eisele said in an email.
In the meantime, international aid groups are still helping West Africa recover from Ebola, which was finally stamped out of Liberia last summer after a series of flare-ups postponed the declaration of victory over the disease.
One challenge will be the possibility of the reignition of the outbreak via sexual transmission, after scientists determined the virus can remain in semen for several months. Health officials have been monitoring male survivors, and very few still test positive, so the risk in West Africa is “very close to zero by now,” WHO spokesman Tarik Jasarevic said.
Still, the long-term host of the disease — probably a bat — remains in the region, so the virus could spill into humans again, said Amesh Adalja, a senior associate at the University of Pittsburgh Center for Health Security.
The West African nations struck by the 2014-2016 epidemic are now part of a group of historically at-risk nations — Democratic Republic of Congo, Sudan, Gabon and Uganda — that have seen outbreaks of varying sizes over the past four decades.
“Nations that suffered during this outbreak are recovering and hopefully have some infrastructure in place to face Ebola or any other infectious disease emergency they may face,” Dr. Adalja said.
‘Bad part of history’
On the ground, Liberians sometimes talk about the outbreak the way they discuss the civil war that tore the country apart in the 1990s, according to Stephen Farshing, a program coordinator for Global Communities, a nonprofit that had been working on sanitation projects in Liberia when the Ebola epidemic broke out.
“Considering the last case was almost nine months ago and the previous was five months before that, people look at is as a bad part of history,” he said.
He said the government is still trying to establish an accountable, self-sustaining health system, though it made tremendous strides in improving its sanitation and burial practices to avoid environmental risks.
The outbreak also prodded international corporations to reexamine their policies. From hygiene habits to evacuation plans, companies need to be nimble enough to respond to sudden health threats, said Dr. Myles Druckman, senior vice president and regional medical director at International SOS, a company that advises clients on global medical and security issues.
“They need to be able to respond quickly, and in some places be more proactive than the government authorities,” he said.
American tax dollars are also at work, even if the outbreak, for all purposes, ended a long time ago in places far away.
The Department of Health and Human Services said it is still spending down $710 million of the $2.56 billion that Congress gave it in late 2014 as part of an emergency package to fight Ebola and other diseases at home and abroad.
The money has been used to support thousands of aid workers in Liberia and help countries as far away as Pakistan build up labs and identify harmful pathogens as part of a long-term plan, known as the Global Health Security Agenda, to prevent, detect and respond to emerging health threats.
“We’ve been able to make very good progress basically helping other countries find and stop outbreaks there so we don’t have to fight them here,” said Dr. Tom Frieden, director of the Centers for Disease Control and Prevention.
He said the CDC’s $1.8 billion portion of Ebola money is essentially spent, but that it forfeited more than $60 million — some it had hoped to spend over the next two years — to shore up the Zika fight, as Congress struggled to agree on how to fund the mosquito-borne disease that emerged as a threat in early 2016.
As a result, Dr. Frieden said the agency is struggling to support field teams that were sent to West Africa to help those countries shore up their health systems should Ebola reemerge.
Meanwhile, the National Institutes of Health’s infectious diseases branch said it spent $238 million on Ebola — more than half of it on developing vaccines, the rest on therapeutics and diagnostic testing — in the past two years, and is set to spend $40 million more in the fiscal year ending Oct. 1.
NIH has been supporting several vaccine candidates, including a promising one developed by GlaxoSmithKline that uses a chimpanzee cold virus and developed an immune response in early testing. It was also involved in early trials of the zVSV-ZEBOV trial vaccine in Liberia, though cases started to vanish before that trial could gather good data.
The focus shifted to Guinea, where the vaccine proved to be highly effective amid that country’s struggle to wipe out the disease.
Dr. Fauci said NIH recently submitted a paper on the Merck vaccine’s ability to produce an immune response, fortifying the results out of Guinea, where the WHO used a “ring” approach akin to the strategy used to stamp out smallpox.
Whenever a new Ebola patient emerged, researchers formed a ring by tracking down people who lived or visited with the person, other close contacts and then “contacts of contacts,” totaling an average of 80 people. In all the team vaccinated 117 rings.
At first the rings were sorted so that some received the shots immediately, while others received it after a three-week delay. Only adults were vaccinated. Early results were promising, however, so researchers offered the vaccine immediately to people aged 6 years or older in every ring.
Dr. Fauci said it is still unclear how durable the vaccine is — for instance, if the Guinea recipients would still be protected if the disease reemerged today — though he’s seeing momentum as the fruits of their Ebola research come in.
“Even though it’s off most people’s radar screen,” he said, “it’s not off our radar screen.”