New Ebola vaccine brings hope to DR Congo | Science| In-depth reporting on science and technology | DW | 13.10.2019
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Infectious diseases

New Ebola vaccine brings hope to DR Congo

Many in the Democratic Republic of Congo have been waiting for this moment: A new vaccine to battle the Ebola outbreak is about to be released. It could reach broader parts of the population than earlier attempts.

The second-deadliest Ebola epidemic in the world has been raging in the Democratic Republic of Congo for over a year. More than 3,200 people have been infected with the virus and, up to this week, at least 2,144 people have died from the illness.

But now there are signs of progress in the battle to stop the outbreak. The World Health Organization (WHO) reports that the number of reported new infections is declining. Only 14 people were confirmed in the first week of October — making it the lowest number in a year. At the peak of the Ebola epidemic, in April, the number of new infections was 126 per week.

In addition, all recently reported cases are concentrated in a relatively limited area, close to the Ugandan border. It is a geographical triangle between the towns of Mambasa, Mandima and Komanda in Ituri province and Oicha in North Kivu province.

However, the region has been gripped by armed conflict for decades. The ongoing violence hinders medical efforts and also makes local communities wary of outsiders, further limiting the effectiveness of medical interventions.

Read more: Ebola: What is the best vaccination strategy?

Portrait of infectious disease expert Marylyn Addo

Addo hopes the new Ebola vaccine will help overcome the epidemic

Vaccination for many in risk areas

The cities of Beni and Goma in North Kivu province have also received positive news. From November, physicians will use a new vaccine from Johnson & Johnson that is better suited for broad-based prophylaxis than Merck's existing VSV-EBOV vaccine.

"The vaccines are very different in strategy," says Dr. Marylyn Addo. "The vaccine that is currently being used, takes effect after only one shot — very quickly. The new vaccine, however, consists of two components that need to be administered at eight-week intervals." 

Read more: Tanzania 'not sharing' data on suspected Ebola cases: WHO

Addo, an infectious disease expert researching emerging infections for the Bernhard Nocht Institute for Tropical Medicine, says: "The new vaccine is not really suitable to immunize contact-persons in the case of acute suspected or confirmed Ebola cases. It is more likely to be used in areas that are at risk. There, the whole population could be vaccinated prophylactically."

Although the new vaccine does not work so quickly, it has other advantages. "It is easier to produce and does not need to be cooled as much," she says. 

 While Merck's current fast-acting vaccine has to be cooled to minus 60 to 70 degrees Celsius, the new vaccine only needs to be cooled to minus 20 degrees Celsius. "These are all advantages. In this respect, we hope that doctors can reach more people with the new vaccine," she says. 

Read more: World unprepared for pandemic, panel warns

More vaccine doses available

Because it is easier to produce, the new vaccine will probably help vaccinate many more people. So far, around 235,000 people have been immunized with the first vaccine. Approximately the same number of vaccine doses are currently available.

About 1.5 million doses of the new vaccine are already available even though the vaccine is still in Phase III of approval, a stage that requires the medicine to show its effectiveness. "This is, of course, one way to find out whether the vaccine is really effective in Phase III. It has shown very good tolerability and a very good immune response. Therefore, we assume that it will also protect against the virus, but that has not been proven yet," says Addo.

That is precisely why the people living in the four cities affected, as well as in Beni and Goma, should be vaccinated. Residents here would otherwise have no chance of accessing vaccination because they do not belong to the circle of those who have had — or still have — direct or indirect contact with Ebola patients. "If you want to prepare a city for an emergency or vaccinate health workers now, this new vaccination is a good choice," says Addo. 

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Complete immunity to virus remains unrealistic

If and when the Ebola outbreak is overcome, the immediate question arises: how will authorities vaccinate against Ebola in the future in order to be prepared for new outbreaks.

The problem is that Ebola is transmitted by wild animals. Since 1967, cases have occurred in a vast area of sub-Saharan Africa, from Uganda in the east to Guinea and Sierra Leone in the very far west of the continent. Almost 5,000 kilometers lie between those countries and hundreds of millions of people live in these potential Ebola risk areas. It is therefore unrealistic to expect, that the health authorities will ever be able to vaccinate every single person prophylactically. They will only be able to react to acute outbreaks.

With the two vaccines, they now have a better arsenal of weapons to target the virus. In addition, there are better medicines for patients who are already infected with the illness. With two antibody therapies, doctors have succeeded in reducing the Ebola mortality rate from 67% to 35%.

"Considering that we have only known Ebola since 1967, we have made a major step forward. And we have to build on this," says Addo confidently.

With all the fear of Ebola, says Addo, it is important to not forget about the more common infectious diseases, which cost many more lives. "We have many challenges when it comes to vaccinating. Congo is currently experiencing the world's largest measles outbreak and also a very large cholera outbreak," she says. 

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