First Ebola vaccine prequalified by WHO for use in high-risk countries

By Sally Robertson, B.Sc.Nov 14 2019

The world's first Ebola vaccine has been prequalified by the World Health Organization (WHO), a key step in speeding up its licensing, access, and use in countries most at risk of Ebola outbreaks.

Image Credit: Leonie Broekstra / Shutterstock.com

This is the fastest vaccine approval process ever to have been conducted by the WHO.

Prequalification of the vaccine means it meets the WHO’s quality, safety, and efficacy standards. The WHO prequalified the vaccine just two days after the European Commission granted conditional marketing authorization for the vaccine. This prequalification means United Nations agencies can now obtain and roll-out the vaccine in high-risk countries.

A "historic step" in the fight against Ebola

WHO Director-General, Tedros Adhanom Ghebreyesus called the development a “historic step” towards making sure the life-saving vaccine is made available to the people who most need it:

Five years ago, we had no vaccine and no therapeutics for Ebola. With a prequalified vaccine and experimental therapeutics, Ebola is now preventable and treatable. The development, study, and rapid prequalification of this vaccine show what the global community can do when we prioritize the health needs of vulnerable people.”

Tedros Adhanom Ghebreyesus, Director-General of World Health Organisation

The second largest and second deadliest outbreak on record

Ebola, which is spread through contact with infected blood or other bodily fluids, is often fatal. According to the WHO, the virus kills between 25% and 90% of people who contract it.

The new injectable vaccine, called Ervebo, is manufactured by the US pharmaceutical and life sciences company Merck. It has proved effective at protecting against the Ebola Zaire virus and is currently already being administered in a “compassionate use” capacity in the Democratic Republic of Congo (DRC).

The DRC has recently seen the second largest and second deadliest outbreak of Ebola on record. Congolese health officials reported that more than 3,000 people in the DRC have tested positive for Ebola since August 2018 and that more than 2,100 people have died as a result.

A second vaccine is also expected to be deployed

A second experimental vaccine manufactured by Johnson & Johnson (J&J) is also expected to be deployed in the city of Goma as part of a clinical trial, according to Congolese officials. That vaccine, which requires two doses given 56 days apart, is going to be offered to around 50,000 people living in the city, which has a population of two million.

It's vital that we intensify our efforts. That's why we're working with international partners to provide our response teams with another tool to fight and ultimately stop the spread of this terrible disease."

Dr Eteni Longondo, DRC Minister of Public Health

The J&J vaccine will be offered to adults and children aged over one year who reside in two areas of Goma.

Jeremy Farrar, director of the Wellcome Trust, has called the trial a critical step forward: "Previous trials have shown that the J&J vaccine produces an immune response, a good indication it will be protective against the Ebola virus."

There is "no contest" between the two vaccines

Daniel Bausch, director of the UK Public Health Rapid Support Team and one of the researchers leading the trial, has said there is “no contest” between the two vaccines, with each of them having their advantages and disadvantages.

The Ervebo vaccine, which is given to individuals who come into contact with patients infected with Ebola, could be useful during an outbreak, while the J&J vaccine could protect people who have not yet been exposed to the virus.

"The J&J vaccine is not ideally suited to an outbreak setting, primarily because it requires two doses to provide the optimal immunity," explains Bausch. However, it "may provide longer-term immunity, and may be associated with fewer side-effects than a live virus vaccine, like the Merck one."

Skeptical communities will present a major challenge

One major challenge immunization teams will face in trying to deploy the vaccine is the skepticism among some communities, which has been fuelled by misinformation and rumor. Since the outbreak began in August 2018, about 200 health centers have been attacked, so introducing the vaccine into such communities will require a major effort.

The vaccine is going to be administered by immunization teams from the medical charity Médecins Sans Frontières (MSF).

Using two different vaccines in nearby areas might result in misconceptions, which means that community engagement will be crucial before and during the deployment of the second investigational vaccine."

John Johnson, MSF's project leader on Ebola vaccination

EU Ebola Coordinator, Christos Stylianides, says: “The EU is supporting international efforts to combat Ebola on all fronts, from vaccine development to delivering humanitarian aid on the ground. We will continue assisting the fight to tackle [the] epidemic for as long as it takes.”