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Home / Health / The Ebola outbreak in the Democratic Republic of Congo faces a serious weapon: a vaccine

The Ebola outbreak in the Democratic Republic of Congo faces a serious weapon: a vaccine



Four thousand doses of a Ebola vaccine have just arrived in the Democratic Republic of the Congo where an outbreak of the deadly virus is still ongoing.

Merck's rVSV-ZEBOV is the first highly efficacious Ebola vaccine and is expected to be a very useful tool for the DRC outbreak, involving 41 reported cases and 19 deaths to date.

"This is the first time it has been used in a new outbreak," said John-Arne Røttingen, Director-General of the Norwegian Research Council, which was working on the Ebola vaccine trial. "[Health officials] will vaccinate early and hopefully before the epidemic begins."

This is a rare public health success story involving a neglected disease and worth celebrating.

The world community devotes more money to fighting baldness and erectile dysfunction than developing treatments or "neglected tropical diseases" vaccines, such as Ebola, which infect more than a billion of the world's poorest people. And when these flagella attract funding, they mostly come from defense budgets (remember, Ebola is considered a potential bioterror weapon) or charities.

So it is not surprising that, despite the more than 40 years since the discovery of Ebola in 1976, a vaccine that prevented the spread of the virus was not available until recently.

The West Africa-Ebola epidemic from 2013 to 2016 caused more than 11,000 deaths – but also triggered a financial boost to prevent the disease. The tragedy has led the public and private sectors to push one of the [19609010] half-developed Ebola vaccine candidates through the clinical trial process.

Already this week, the world could begin to see the impact of these efforts. Every previous outbreak of Ebola has been eradicated by a proven and true strategy called "contact tracking": isolating the sick people before they had the chance to infect anyone and thus disrupt the human transmission chain.

This time, health officials have a vaccine ready to use early in an outbreak. (So ​​far, the clinical trials of the rVSV-ZEBOV vaccine have included only people who have been experiencing simmering outbreaks for some time now.)

If the experimental vaccine contributes to the spread of Ebola in the DRC, it could lead to major outbreaks Variety – like the ones we saw in West Africa a few years ago – will be a thing of the past.

The Ebola vaccine was 100 percent effective in clinical trials – but it was on the shelf for more than a decade before it was tested

There are five types of Ebola, four of which have caused the disease in humans: Zaire , Sudan, Taï Forest and Bundibugyo. (The fifth, Reston, was discovered in Virginia and has only infected monkeys.) The rVSV-ZEBOV was designed to protect against Zaire, the type of Ebola that most commonly affects humans.

But it does not actually contain any deadly Ebola virus – it replaces a gene from a harmless livestock virus, vesicular stomatitis, with a gene that codes for an Ebola virus surface protein to deceive the body's immune system.

The vaccine developed by the Public Health Agency of Canada in 2003 proved to be 100 percent effective in monkeys. However, due to the lack of interest of pharmaceutical companies before the West Africa outbreak, it literally sat on the shelf until it was licensed to Merck in 2014.

During the West Africa outbreak, researchers – from the World Health Organization, Guinea's Ministry of Agriculture and Pharmaceuticals Health, Public Health England and other international partners have been working together to help establish a clinical trial to test the vaccine. In 2015, they released impressive preliminary results in the Lancet which showed that anyone who got the shot immediately after contact with an Ebola victim did not get the virus.

One year later, they unveiled their final results, also in Lancet, and they were just as amazing. The vaccine has been tested in Guinea and Sierra Leone in nearly 12,000 people. Among the 5,837 people who received the vaccine, no Ebola cases were registered. In comparison, there were 23 cases in the control group who did not receive the vaccine.

"This study, which confirms the 100% efficacy of the rVSV-Ebola vaccine, is an amazing achievement," Jeremy Farrar, director of the Wellcome Trust, said at the time the results came out. "We have shown that by working across international borders and across sectors, we can quickly develop and test vaccines and use them to end epidemics."

The surge of interest in Ebola has prompted the development of a new organization called CEPI, the Coalition for Epidemic Preparedness Innovations. The company is funded by the UK's Wellcome Trust, the Bill & Melinda Gates Foundation and the governments of Germany, Japan and Norway with nearly half a billion dollars and focuses on providing vaccines for the next pandemic.

CEPI has worked with Merck to bring the Ebola vaccine through clinical trials, although it is still not commercially available. In 2016, the public-private vaccines partnership paid GAVI Merck to store doses of the vaccine and also helped Merck's regulatory efforts to collect more data on the vaccine and have it approved.

So far, health officials have not been able to deliver the vaccine fast enough at the onset of an outbreak. Only last year, an outbreak of Ebola in the DRC ended before the vaccine had to be administered.

The use of the vaccine could make this outbreak historic

This year is different. At the request of the DRC government, the vaccine is being field-tested for the first time at the epicenter of the outbreak in Bikoro, in the northwestern province of Ecuador.

Bikoro is located in a very remote area of ​​a country with poor road infrastructure, but it is located on a lake that connects the busy Congo and Ubangi rivers. People infected with Ebola travel to big cities like the capital Kinshasa or near Brazzaville – a potential public health nightmare that officials are trying to prevent quickly.

Last year, the DRC government approved a clinical trial protocol for the vaccine, according to Science Co's Jon Cohen. Since the vaccine is still considered experimental, it will be distributed to volunteers for "compassionate use."

Médecins Sans Frontières, WHO and the DRC Ministry of Health will work together to administer the vaccines. (And also keep the vaccines stored at cold temperatures – minus 76 to minus 112 Fahrenheit – which protect their effectiveness.)

"This is not a simple logistical effort," said Peter Salama, WHO's Health Emergencies Program a news conference last week. "It's not like we're having a polio campaign with oral polio vaccines where we're going to put it into action right now, a highly complex, sophisticated operation in one of the world's toughest areas."

One of the most intriguing Properties of the vaccine – aside from its apparent safety and efficacy – is the way it is used. Health officials will use a so-called "ring vaccine", a public health method used to eradicate smallpox in the 1970s. It involves immunizing the immediate contacts – friends, family, roommates, neighbors – a person who suffers from a virus to create a protective ring around them to stop the transmission.

Once a new Ebola case is diagnosed, health workers will track the person's contacts and then vaccinate them to prevent anyone else from getting sick. They are monitored for 84 days, the WHO says, to see if Ebola or any side effects develop. So, this new technology will be used alongside the public health of the old school

Even if the outbreak of the DRC remains small – and hopefully does – it could be historical.


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