Researchers in Uganda have launched the largest-ever trial of the experimental Ebola vaccine that is expected to be deployed in neighbouring Congo, where a deadly outbreak has killed over 1,800 people.


The trial of the Janssen Pharmaceuticals vaccine involves up to 800 people in the western district of Mbarara and is supported by Doctors without Borders and the London School of Hygiene and Tropical Medicine. Pontiano Kaleebu, a Ugandan researcher who leads the trial, said 2nd August that he regrets that the Janssen vaccine has not yet been deployed in Congo. The health minister there who stepped down last month had argued against its deployment, saying a second vaccine could create confusion on the ground.

Already more than 180,000 people in Congo's yearlong outbreak have received an experimental but effective Merck vaccine, but health experts worry about the availability of doses as the virus now spreads in a major city, Goma, along the Rwanda border. The wife and 1-year-old daughter of the man who died this week of Ebola in Goma now have the disease. Both the wife and child were doing well in treatment, Congo's new Ebola response coordinator, Jean-Jacques Muyembe, told reporters on 2nd August.

But he warned that about half of the cases in this outbreak are going undetected and at that rate "this epidemic could last two or three years. " The current goal is to strengthen surveillance and bring the detection rate to 80 percent," he said.

Health experts have watched with dismay as the promise of the Merck vaccine in this outbreak has been largely overshadowed by severe challenges to virus containment efforts including rebel attacks and community resistance in a part of Congo that had never experienced Ebola before. The Janssen vaccine has already been tested in about 6,000 people, most of them Africans, Kaleebu said. "We are excited about this (trial) because this is one of the promising vaccines," he said. 

"It's one of those vaccines that have shown a lot of promise in animal studies but also in other trials that have been conducted."  Ugandan researchers said the new trial is expected to last two years and will test how long any protection from Ebola would last. Juliet Mwanga, a co-investigator on the trial, said there is the need "to study many vaccines" in light of Congo's epidemic.

Uganda has had multiple Ebola outbreaks in the past. While it is currently free of the virus, three people died in June after crossing into the country's Kasese district on an unguarded footpath. Their family members were taken back to Congo for treatment. The Ebola virus can spread quickly and be fatal in up to 90 percent of cases. Symptoms include fever, vomiting, diarrhea, muscle pain and at times internal and external bleeding. 

The virus is most often spread by close contact with bodily fluids of people exhibiting symptoms and with contaminated objects such as sheets. Health care workers are often at risk.