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WHO seeking to bring Merck Ebola vaccine to latest outbreak area

ebola_may_19_2017.jpg

By Nuala Moran
Staff Writer

 

LONDON – The World Health Organization (WHO) is laying the groundwork for Merck & Co. Inc.'s unlicensed VSV-ZEBOV Ebola vaccine to be used to combat the new outbreak of the virus that started last month in the Democratic Republic of Congo (DRC).

If all the pieces fall into place, a vaccination campaign could start "in about a week," according to Peter Salama, WHO executive director, Health Emergencies Programme.

However, there are significant hurdles to be navigated first. The outbreak is in an extremely remote, strife-torn part of DRC where there are only 20 kilometers of paved roads, no telecommunications network and limited health facilities.

The difficulties posed by the lack of infrastructure are further compounded by the fact that the vaccine needs to be kept at minus 80 degrees centigrade. "In an area without roads and communications that is going to be an enormous challenge," Salama said.

Before any VSV-ZEBOV can be moved from the stockpile in the U.S., the government of DRC will have to make a formal request to allow compassionate use of the unlicensed product. There will also have to be a detailed, ethically approved study protocol, subjects must give informed consent and the systems must be in place to track adverse events. That calls for skilled people to be on the ground and WHO is working with partners, including Médecins Sans Frontières and the Red Cross to pull teams together.

Salama said the government of DRC has been made aware VSV-ZEBOV is available. "They are in the process of considering it. The health minister [Oly Ilunga Kalenga] has asked regulators to look at the protocol," he said. WHO is committed to working with Merck and others to implement a vaccination program if the government gives the go-ahead.

As of Wednesday, there have been 20 cases of Ebola, of which two have been confirmed by laboratory tests and 18 are suspected. The index case was a man who died on April 22. Since then, his carer and a motorcycle driver who took him to seek medical assistance have died, too.

WHO was first alerted to a cluster of unexplained hemorrhagic illness and deaths on May 9 and the first case was confirmed as Ebola virus infection on May 11.

The emergency management team at WHO was then activated and other partners mobilized.

On Wednesday, Kalenga and Allarangar Yokouidé, WHO's representative in the DRC, carried out a first visit to assess the outbreak in Nambwa, epicenter of the disease, in the Likati health district, Bas-Uélé Province, which is located more than 1,400 kilometers from the country's capital, Kinshasa.

On that visit, the health officials were accompanied by 12 experts, including epidemiologists, logisticians, psychologists and data managers, who conducted a rapid assessment of outbreak.

Salama said the immediate focus is on surveillance, community engagement and following the 400-plus contacts of the 20 identified cases. The first Ebola treatment center has been established, a mobile laboratory is being deployed and protective clothing and equipment is being shipped in.

This is the eighth outbreak of Ebola in DRC since the first-ever case of the infection was identified there in 1976. During the 2013 - 2016 epidemic there were 66 cases in the country.

"We believe the government has strong experience of dealing with Ebola outbreaks," Salama said. "But you can't underestimate the logistical challenges – as of now we don't know the extent of the outbreak."

ring vaccination trial

The proposed VSV-ZEBOV program will not involve the whole population, but will be a ring vaccination, in which immediate contacts of patients infected with Ebola are immunized.

That was the approach used in the phase III study of VSV-ZEBOV, which took place in Guinea during the 2013 – 2016 Ebola epidemic. That trial, published in December 2016, showed the vaccine to be 100 percent effective, with no one who received VSV-ZEBOV contracting the virus. (See BioWorld Today, Dec. 27, 2016.)

Salama said the work on contact chasing and epidemiology will form an important pillar in deploying VSV-ZEBOV. "This detective work is critical for implementing a ring vaccination program," he said.

In the Guinea trial, 10,000 people were vaccinated. GAVI, the vaccine alliance, gave Merck $5 million to manufacture a stockpile of 300,000 doses on the understanding that VSV-ZEBOV would be submitted to the FDA and EMA for approval by the end of 2017. The vaccine has FDA breakthrough therapy and EMA Prime (priority medicine) designations.

Merck also submitted VSV-ZEBOV to WHO's emergency use and assessment listing procedure. The application was considered by WHO's strategic advisory group of experts (SAGE), meeting in Geneva from April 25 to 27.

The group recommended that in the case of outbreaks the vaccine be promptly deployed under the expanded access framework, using ring vaccination. That should include contacts and contacts of contacts; local and international health care and front line workers in the affected areas.

An expanded access study protocol should be implemented and the study should be used as an opportunity to accumulate additional information on VSV-ZEBOV's safety, efficacy and effectiveness, SAGE said.

VSV-ZEBOV, a recombinant, replication competent vesicular stomatitis virus expressing a surface glycoprotein of Zaire Ebola virus, was initially engineered by scientists at Canada's Public Health Agency. It was subsequently licensed to Newlink Genetics Corp., of Ames, Iowa, which did a deal with Merck in late 2014. (See BioWorld Today, Nov. 25, 2014.)

The phase III Guinea ring trial was funded by WHO, the Wellcome Trust, the U.K. Department for International Development, the Norwegian Ministry of Foreign Affairs, the Norwegian Institute of Public Health, the Public Health Agency of Canada and Médecins Sans Frontières.