Merck’s Ebola vaccine rVSV-ZEBOV has been utilized in several outbreaks, including an ongoing one in the Democratic Republic of Congo, and its value has gone beyond stopping the disease to transforming people’s attitudes toward Ebola as well.
In the current outbreak, over 96% of people who were offered the vaccine had taken it, Mike Ryan, the World Health Organization’s assistant director-general for emergencies said during a live Facebook interview last Thursday. In what Ryan described as “high community demand," about 4,625 doses had been given as of last Wednesday.
As Ryan sees it, the vaccine is “transforming” people’s attitude on community level. Previously when healthcare workers came, villagers would be in terror, with no idea what fate would befall them, said Ryan. “Now we bring the vaccine, we’re bringing hope.”
“If we can get to a point where we have an effective vaccine, if we can get to the point where we have effective therapeutics, then I think the terror that’s been associated with viral hemorrhagic fevers, and particularly with Ebola, hopefully will begin to decrease, and we’ll able to contain these outbreaks in the future much more effectively,” said Ryan.
Merck’s vaccine is currently used under an emergency protocol, as it hasn’t gained official licensure. The company told FierceVaccines in early August that it's preparing critical components of required documents and is expecting to file for approval with the FDA and the European Medicines Agency in 2019, a further delay after it pushed the projected filing date to this year.
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The latest outbreak in DRC was declared on Aug. 1, just days after health officials declared the end of the previous one. As of Sunday, there were 121 confirmed or probable cases and 81 deaths.
Once the virus was confirmed to be the Zaire strain, which rVSV-ZEBOV targets, the WHO and local health ministry quickly deployed the vaccine in a “ring” fashion. It works by immunizing all contacts around the cases and contacts to contacts to break the transmission chain.
Credit was given to the Merck shot in stopping previous outbreaks, including the most recent one, where it was given to about 3,500 people in DRC and helped suppress the eruption within four months. Prior to that, in a ring study in Guinea, the vaccine protected all people who got it immediately after exposure.
In addition to the vaccine, Ryan said five experimental therapeutics to treat infected patients are being used under compassionate use programs, including antivirals and antibodies. As of Wednesday, 19 people had been treated by some of the drugs.
Deployment of the vaccine and the new drugs could be tricky this time around, as the affected regions might include “red zones” where armed groups are present. Ryan said that the United Nations peace corps is helping ensure security for health workers.