Uganda’s Ebola Success Forces Revamp of Vaccines Trial

Uganda on Thursday received two more potential vaccines for a trial against the Sudan strain of the deadly Ebola virus. Uganda has recorded 142 confirmed cases and 55 deaths since the September outbreak but has had no new cases since late November. While having no active cases is welcomed, it also means the trial will have to be revamped to test the vaccines’ effectiveness.

The World Health Organization handed Ugandan officials more than 4,000 doses of Ebola trial vaccines on Thursday — 2,000 of the Indian Serum Institute’s Oxford vaccine and just over 2,000 from U.S. manufacturer Merck.

It brings the total number of Ebola vaccine doses available in Uganda to more than 5,000 after an initial 1,000 from the U.S.’s Sabin Vaccine Institute were received last week.

The vaccines were sent for use in a trial against an outbreak of the Sudan strain of the virus that since September killed 55 people.  

But Uganda has not recorded any new Ebola infections since November 27.

While that success in halting the outbreak has been welcomed, Uganda’s Health Minister Jane Ruth Aceng said it also means plans will have to be changed to test the vaccines on people who had contact with those infected.

“There are no more cases and no more contacts,” she said. “So, the scientists are evaluating alternative research designs to assess the usefulness of these vaccines in protecting people against Ebola infection.”

The principal investigator of the Ebola vaccine trial, Dr. Bruce Kirenga, said his team is engaging communities but will have to wait for a global expert meeting on January 12 to finalize and approve the trial revamp.

“The trial that we have is designed to answer three questions, abbreviated as I-S-E. Immunogenicity, Efficacy, and Safety,” he said. “These vaccines, can they induce immunity in people if they are administered? Are they safe? Can that immunity prevent disease?”

Yonas Tegegn Woldemariam, the WHO country representative for Uganda, said the country’s success in stemming the outbreak means it has gained the capacity, knowledge, and skills to carry out an Ebola Sudan strain vaccine trial.  

He said the trial is still worth doing, even if Uganda doesn’t register another Ebola infection.  

“Uganda would contribute from this trial, another tool for us to manage Ebola Sudan if it ever happens in a major population,” he said.

Since Uganda announced the Ebola outbreak 100 days ago, aside from confirmed cases and deaths, the country recorded 87 discharges.

Despite having no new cases since November, Uganda will have to wait until January 10 to declare the country Ebola-free.   


There is currently no effective vaccine available for the Sudan strain of Ebola.


The WHO says Uganda’s last Ebola outbreak in 2019 was triggered by the more common Zaire strain.  


Uganda last reported an outbreak of the relatively rare Sudan strain in 2012.

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