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What's Keeping Scientists From Vanquishing Ebola?

This story appears in the May 2019 issue of National Geographic magazine.

In the 25 years since my book The Hot Zone traced the emergence of extremely lethal viruses, one of them has proved to be the most destructive: Ebola. At this writing, Ebola has killed hundreds in the Democratic Republic of the Congo, in the second largest outbreak since the virus was identified in 1976. The largest—from 2014 to 2016 in three West African nations—resulted in almost 30,000 cases, nearly half of them fatal. Fierce international efforts helped quell Ebola that time, but there are no assurances that the virus (above) has ended its assaults on the human species. Ebola is hard to arrest for many complicated reasons (below). But scientists keep trying—and what they learn will equip us to face this virus, and possibly worse, in the future.

1. The vaccine's requirements Ebola vaccine has to be kept cold. But in tropical areas where little refrigeration is available, the vaccine can quickly become useless. And we don't yet have a dried or otherwise nonperishable form of the vaccine.

2. Constraints and costs of new drugs There are experimental, genetically engineered drugs for Ebola, but it's not yet clear if they'll be broadly effective, and affordable enough that they'll be feasible for mass treatment of Ebola victims.

3. The failure of a technique that stopped past viruses In 1966, during a large outbreak of smallpox virus, vaccinators tried a technique called ring vaccination with great success: They vaccinated people in a ring around the infected person. This trapped the virus inside a wall of immune people and stopped it from spreading. But attempts to use the technique with Ebola have run into problems. Ring vaccination requires a stable government or other authority maintaining civil order. The areas with Ebola outbreaks in the Democratic Republic of the Congo are controlled by violent militias that won't let vaccinators do their work.

4. Gaps in scientists' understanding of how Ebola kills Ebola remains mysterious. It is unbelievably aggressive in the human body, but scientists still don't understand all the virus's mechanisms. The great military strategist Sun Tzu said, "Know the enemy." We're still getting to know Ebola. When we finally do, we'll know the paths to defeat it.

Watch the trailer for The Hot Zone

In 1989, Ebola landed on U.S. Soil. After appearing in a research lab in D.C., a heroic U.S. Army scientist put her life on the line to prevent an outbreak. Inspired by true events and starring Julianna Margulies, watch The Hot Zone on National Geographic.

Ebola: How A Killer Disease Was Stopped In Its Tracks

By Dr Josie GoldingWellcome Trust

A health worker monitors the temperature of a traveller from the DR Congo

One of the world's deadliest viruses, Ebola kills up to half of those it infects. But despite appearing to have all the hallmarks of a potential epidemic, the latest outbreak developed in a very different way.

It was the ninth Ebola outbreak to hit the Democratic Republic of Congo in a decade, killing 29 people and leaving at least 60 children orphaned.

While one death is too many, the West Africa epidemic of 2014-16 claimed more than 11,000 lives and it is hoped that later this week the most recent outbreak will be declared officially over by the World Health Organization.

The relatively small number of deaths follows the use of an experimental vaccine, which may have saved hundreds, or even thousands of lives.

Fragile health system

Although the outbreak began in a remote area, there was a real danger that large numbers could be infected.

It appeared close to neighbouring Central African Republic and the Republic of Congo - a vast area with a great ebb and flow of people and a fragile health system. It is also an area linked by river and road to the capital Kinshasa - home to 10 million people.

The vaccine used, known as rVSV-ZEBOV was already in development during the 2014-16 epidemic. But by the time its effectiveness had been proven, the outbreak was already waning.

When the virus returned in 2018, it could be quickly deployed, once the DRC government had approved its experimental use. This vaccine is designed for use against the Zaire strain of Ebola, which caused both this outbreak and the previous one.

Scientists and health workers set to work tracking all potential transmissions since the first case had been reported.

Front-line health workers, people in contact with confirmed Ebola cases, and their contacts all needed to be given the vaccine.

However, keeping the vaccine safe and making sure it reached the right people was not a straightforward task.

The vaccine must be kept extremely cold, at minus 70C.

This is difficult and expensive to do in a remote environment with unreliable electricity. Alongside the vaccine, fridges and generators had to be flown into the region by helicopter.

Isolation and treatment facilities had to be built, mobile laboratories set up and local laboratory technicians trained to test samples and confirm cases of Ebola.

Gaining consent

For the vaccine to be effective, it had to be given to the right people.

Health workers spoke to patients, their families and the wider community to dispel rumours, build trust and avoid panic.

This, they explained to community leaders, was not a mass campaign.

Vaccinations were given to the Ebola patient, plus a "ring" of friends, family and contacts - as well as healthcare workers and people involved in burials. All had to give their consent.

Identifying and finding all the people suspected Ebola patients had been in contact with was a major challenge because of the location.

Health workers had to travel by motorbike to places where there are no paved roads.

Despite these challenges, there has been high uptake rate and an estimated 98% of those eligible were vaccinated.

What is Ebola?

Ebola is a viral illness that kills between 30%-50% of the people it infects

Initial symptoms include sudden fever, intense weakness, muscle pain and a sore throat

Subsequent stages are vomiting, diarrhoea and - in some cases - internal and external bleeding

Ebola infects humans through close contact with infected animals, including chimpanzees, fruit bats and forest antelope

People are infectious as long as their blood and secretions contain the virus, which can be for up to seven weeks after they recover

Co-ordinated attempt Health visitors travelling by motorbike through a remote area of DRC for a follow-up meeting with a contact

While the vaccination may have helped to save lives, better public health measures also played a crucial role in containing the outbreak.

Treatment centres and isolation zones were set up to reduce the spread of the virus and face-masks, gowns and gloves were used.

Safe burial practices also helped to limit transmission of the virus, as did screening of passengers at international and domestic ports and airports.

There has also been work to reintegrate survivors with their community because in former outbreaks survivors were sometimes ostracised by their families and neighbours.

Ebola's Exponential Growth

Monday, October 13th 2014 - 00:26 UTC

The U.S. Government's Centers for Disease Control warned recently that we could have 1.4 million cases of Ebola by January.

By Gwynne Dyer - Here are two good things about the Ebola virus. It is unlikely to mutate into a version that can spread through the air, as some other viruses have done. And people who have been infected by Ebola cannot pass it on to others during the incubation period (between two and 21 days). Only when they develop detectable symptoms, notably fever, do they become infectious to others, and only by the transfer of bodily fluids.

Here are three bad things about Ebola.

The "bodily fluids" that can transmit it include even the tiniest droplet of sweat: just the slightest touch can pass the virus on. The death rate for those who become infected is 70%. And the U.S. Government's Centers for Disease Control warned recently that we could have 1.4 million cases of Ebola by January.

Since the number of known cases so far is only around 7,500, that suggests that the number of new cases is doubling approximately every two weeks. This is called exponential growth: not 1, 2, 3, 4, 5, 6... But 1, 2, 4, 8, 16, 32.... If you put one grain of wheat on the first square of a chess-board, two on the second, and keep doubling the grains every square, there are not enough grains of wheat in the world to get you to the 64th square.

Exponential growth always slows down eventually, but the question is when? A vaccine would slow it down, and the British pharmaceutical giant GlaxoSmithKline already has one under development, but it is still in an early stage of testing. Human volunteers are now being given the vaccine to check for unforeseen side effects.

If no serious side-effects are found, the vaccine will then be given to health workers in West Africa. A process that normally takes years is being compressed into mere months, and 10,000 doses of the vaccine are already being produced (for the health workers).

But it will be the end of the year before we know if it actually gives a useful degree of protection from the virus.

If it does, then millions of doses would have to be produced and injected into the people of Liberia, Sierra Leone, and Guinea, where Ebola is already an epidemic— or tens of millions of doses if the disease has spread by then to more populous countries like Ivory Coast, Ghana or, worst of all, Nigeria, which has 175 million people.

Until and unless a vaccine becomes available in very large quantities, the only way to stop the exponential spread of Ebola in the affected countries is to isolate the victims, a task that is very difficult in mostly rural countries with minimal medical facilities. Liberia with 4.2 million people, had only 51 doctors and 978 nurses and midwives at the start of the crisis, and some of those have already died or fled.

You don't need to find and isolate everybody who gets the disease to break the exponential pattern. Just isolating 75% of them as soon as they become infectious would drastically slow the spread. But at the moment, in the three most affected countries, only an estimated 18% of the victims are being taken to treatment centers (where, of course, most of them will die).

This is why the most important intervention so far has been the dispatch of 3,000 U.S. Troops to Liberia, with the primary job of creating 17 large tent hospitals and training 500 nurses to work in them. Britain is providing 200 new hospital beds in its former colony of Sierra Leone, with 500 more in the next few months. Cuba has sent 165 health workers, China has sent 60, and France has sent various teams to help its former colony, Guinea.

But with the exception of the American aid to Liberia, it is all woefully inadequate. Nine months after the first case of Ebola was confirmed in Guinea, we are still playing catch-up, and playing it badly. Why is that? Aren't the developed countries also at risk if the virus continues to spread?

Well, no, or at least their governments don't think so. Even without a vaccine, they are confident that their health services can find and isolate any infected people quickly and prevent Ebola from becoming an epidemic in their countries. They are probably right, and so they see the limited help they are sending to West Africa as charity rather than a vital self-interest. But they may be wrong.

As Professor Peter Piot, who first identified the Ebola virus in 1976, said in a recent interview with Der Spiegel, "I am more worried about the many people from India who work in trade or industry in West Africa. It would only take one of them to become infected, travel to India during the virus's incubation period to visit relatives, and then, once he becomes sick, go to a public hospital.

"Doctors and nurses in India often don't wear protective gloves. They would immediately become infected and spread the virus." Then you would have Ebola on the loose in a country of more than a billion people, millions of whom travel abroad each year. All hope of confining the disease to Africa and driving it back down to almost nothing, as was done in previous outbreaks, would be gone.

Ebola Virus Disease