Consortium readies for launch of 2nd Ebola vaccine in DRC

Ebola vaccine campaign
Ebola vaccine campaign

© Dominic Chavez, World Bank / Flickr cc

A global consortium that includes the Democratic Republic of the Congo (DRC) ministry of health, Doctors without Borders, the Wellcome Trust, and CEPI (the Coalition for Epidemic Preparedness Innovations), among other groups, is preparing for the introduction of a second Ebola vaccine to be used in the DRC in the coming days.

And in disease transmission developments, the World Health Organization (WHO) is warning about a woman who apparently survived the disease but contracted it again, as DRC officials note three new cases today.

Half million vaccine doses donated

Janssen Pharmaceutical Companies of Johnson & Johnson, the developers of the Ad26.ZEBOV, MVA-BN-Filo vaccine, will donate 500,000 doses of the vaccine to the consortium, which will distribute and study the tool as part of a large-scale clinical trial in the DRC sponsored by the London School of Hygiene & Tropical Medicine.

Although Janssen's two-dose vaccine has proved to be safe and capable of eliciting an immune response in more than 6,500 humans, there are no human data on its efficacy in preventing Ebola virus infection in an outbreak setting.

Richard Hatchett, MD, CEO of CEPI, said in a press release, "In the midst of this devastating outbreak we welcome the announcement by the Government of DRC to introduce a second experimental Ebola vaccine as part of a clinical trial protocol…. In terms of future global health security, having more than one licensed Ebola vaccine is crucial. It will help improve future supply and enable different vaccines to be used in different outbreak settings and populations, as needed."

The vaccine targets Ebola Zaire, the strain of the virus that's behind the current outbreak in eastern DRC, the world's second largest. Though the outbreak has slowed in recent weeks, it's moving into its 15th month. In May 2019, the WHO's Strategic Advisory Group of Experts (SAGE) on Immunization recommended introducing the Janssen vaccine into the DRC outbreak.

Earlier this year researchers in Uganda launched a 2-year clinical trial of the vaccine among healthcare and frontline workers. CEPI also said the vaccine is being studied alongside the Merck vaccine as part of a large phase 2 randomized, placebo-controlled trial in West Africa, called PREVAC, that began in 2017.

In the DRC, the vaccine will be given to adults and children over 1 year in two doses (one dose of Ad26.ZEBOV, and the second of MVA-BN-Filo), spaced 2 months apart. According to Bavarian Nordic, which partnered with Janssen in 2014 to develop the vaccine regimen, the first dose primes the immune system, and the second aims to enhance the duration of the immune response.

"No single entity can solve this outbreak which has continued for more than a year," said Paul Stoffels, MD, the Chief Scientific Officer of Johnson & Johnson, in the CEPI release. "The global health community has come together in support of this initiative using Janssen's investigational Ebola vaccine regimen to help prevent its further spread."

In an update today, the DRC's Ebola technical committee (CMRE) said immunization efforts with the second vaccine will start in Karisimbi health zone in Goma and will progress from there. Goma is in North Kivu province.

To date 245,085 in the current outbreak have been vaccinated with Merck's VSV-ZEBOV vaccine. Early clinical data on that vaccine shows it prevents Ebola infection in more than 90% of recipients.

Survivor possibly re-infected

Today Reuters reported that WHO and DRC officials are changing rules about who provides care to Ebola patients after the death of a woman who may have contracted the virus a second time. The case challenges the accepted medical theory that Ebola survivors are immune to reinfection.

The WHO said the woman worked as a caregiver in the high-risk "red zone" of a treatment center in Beni. She was assigned to work with Ebola patients because of her assumed immunity to the virus, officials said. She tested positive for Ebola in July and died before she could be readmitted for treatment. She was pregnant at the time of her death.

Reuters said the WHO and DRC officials have crafted new guidelines that warn of the possibility of "incomplete immunity" among survivors who had mild cases of Ebola, low viral loads, or have compromised immune systems because of pregnancy or other illnesses. They also suggest the woman could have tested as a false-positive the first time she was diagnosed as having the virus.

Ebola survivors have been a vital part of the response effort in the DRC, Reuters said, often spending time and providing extended care to children. Their protective gear is less restrictive than other health workers'.

If confirmed, this would be the first case of reinfection with Ebola since the disease was discovered in 1976.

Three new cases

Finally, the WHO's Ebola dashboard shows three new cases today, raising the outbreak total to 3,272, including 2,183 deaths. Five hundred suspected cases are still under investigation.

The WHO also noted a newly confirmed fatality, bringing the death total to 2,183.

In an update published today, the DRC CMRE revealed a location for yesterday's single case: Mambasa.

See also:

Oct 31 CEPI press release

May 7 WHO SAGE recommendation

Oct 31 Bavarian Nordic press release

Oct 31 Reuters story

WHO Ebola dashboard

Oct 30 CMRE report

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