New Ebola vaccine faces key test

May 18, 2018

The experimental Ebola vaccine dubbed rVSV-ZEBOV has shown promising signs that it can contain the spread of the prolific killer virus.

With a new Ebola outbreak in the Democratic Republic of Congo triggering fears of a regional threat, the vaccine is about to face its toughest test.

The single-dose injection—developed by pharma company Merck and funded by the World Health Organization (WHO) and Canada's public health agency—has been approved for use by the Kinshasa government.

Roughly 7,500 doses have been sent to Equateur province in the northwest of the DRC. Here is what we know about the vaccine.

What is rVSV-ZEBOV?

It uses a modified version of the (VSV), which causes illness in rodents, cattle, pigs and horses, but is not dangerous to humans.

The vaccine prompts the human body to develop antibodies against the invader so that when Ebola attacks, the antibodies are quick to identify it and fight back.

Clinical trials involving 16,000 volunteers in Africa, Europe and the United States have indicated it may be 100 percent effective.

The vaccine does not contain any live Ebola virus.

It can trigger side effects like cold or flu-like symptoms and swelling at the point of injection.

Can it stop an epidemic?

The "vaccine is an additional tool," WHO spokesman Tarik Jasarevic told reporters in Geneva on Friday. "It does not replace all the other elements of the response."

Because rVSV-ZEBOV remains experimental and has not been tested in the height of the epidemic, it is premature to assume that it alone can contain Ebola's spread.

The epicentre of the outbreak is also an extremely remote, rural part of DR Congo, making access difficult. WHO has therefore conceded that "getting the vaccination teams to the affected area will be challenging".

The vaccine also has to be stored at temperatures as low as minus 80 degrees Celsius (-112 degrees Fahrenheit), so keeping it stable in an area with poor infrastructure creates additional complications.

Are there enough doses ready?

In addition to the doses that WHO has sent to DRC and a small reserve stock in Geneva, Merck has said it has 300,000 doses ready for the UN's use free of charge, according to Jasarevic.

WHO estimates that for every confirmed Ebola case, 100 to 150 of that patient's contacts should be vaccinated.

That number could go up for urban cases, given the increased frequency of close human contact in cities.

As of Friday, there were 31 suspected or probable cases in the current outbreak, plus 14 that have been laboratory confirmed.

Health workers and other responders—like those tasked with burying Ebola victims—should also be vaccinated, WHO said.

A WHO spokesman told reporters it was a "targeted vaccination" and therefore not for the "general population".

Gavi, the alliance, has given $1 million towards the operational costs in the DRC campaign, in addition to other support donated to WHO.

Jasarevic said the UN health agency was aiming to start vaccinations in Equateur as soon as possible.

Explore further: Congo's health ministry says doses of Ebola vaccine arrive

Related Stories

Congo's health ministry says doses of Ebola vaccine arrive

May 16, 2018
Thousands of doses of the experimental Ebola vaccine have arrived in Congo's capital amid the latest outbreak of the deadly disease, the health ministry said Wednesday.

Congo approves use of experimental Ebola vaccine, WHO says

May 14, 2018
Congo has agreed to allow the World Health Organization to use an experimental Ebola vaccine to combat an outbreak announced last week, the WHO director-general said Monday.

Ebola reaches an urban area in Congo. What now?

May 17, 2018
The global health community gulped Thursday with the announcement that a case of Ebola had been confirmed in a city of more than 1 million in Congo, bringing the latest outbreak of the often deadly hemorrhagic fever out of ...

Congo's Ebola outbreak reports first confirmed urban case

May 17, 2018
Congo's latest Ebola outbreak has spread to a city of more than 1 million people, a worrying shift as the deadly virus risks traveling more easily in densely populated areas.

WHO reports new Ebola case in DR Congo, vaccine this week

May 14, 2018
The head of the World Health Organization said Sunday there has been another reported case of Ebola in the Democratic Republic of Congo and that an experimental vaccine to fight the disease is expected to become available ...

'Major, major game-changer': Ebola spreads to big Congo city

May 17, 2018
Congo's Ebola outbreak has spread to a crossroads city of more than 1 million people in a troubling turn that marks the first time the vast, impoverished country has encountered the lethal virus in an urban area.

Recommended for you

Deadly Rift Valley fever: New insight, and hope for the future

July 19, 2018
Health control measures alone could be ineffective in the long term fight against the deadly Rift Valley fever which affects both humans and animals, a new study in the journal PNAS reports.

New guidelines to diagnose, manage rare endocrine disorders

July 19, 2018
International guidelines have been published for the first time to help doctors around the globe diagnose and manage patients with a very rare set of endocrine diseases known as pseudohypoparathyroidism and its related disorders, ...

Overuse of antibiotics not what the doctor ordered

July 19, 2018
With increased use of antibiotics worldwide linked to growing antibiotic resistance, a world-first study co-authored by a QUT researcher has highlighted the growing impact of non-prescription supply of antibiotics in community ...

Alcohol-related cirrhosis deaths skyrocket in young adults

July 18, 2018
Deaths from cirrhosis rose in all but one state between 1999-2016, with increases seen most often among young adults, a new study shows.

Hidden blood in feces may signal deadly conditions

July 17, 2018
(HealthDay)—Even if it's not visible to the naked eye, blood in the stool can be serious—a sign of a potentially fatal disease other than colon cancer, new research suggests.

Childhood abuse linked to greater risk of endometriosis, study finds

July 17, 2018
Endometriosis, a painful condition that affects one in 10 reproductive-age women in the U.S., has been linked to childhood physical and sexual abuse, according to findings published today in the journal Human Reproduction.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.