On Dec. 9, 2022, the World Health Organization (WHO) announced that the first doses of one of the three candidate vaccines against Sudan ebolavirus had arrived in Uganda one day earlier. These were evaluated in a clinical trial called the Solidarity Against Ebola or Tokomeza Ebola.

The arrival of the 1200 doses of candidate vaccines just 79 days after the outbreak was declared on September 20 marks a historical milestone in the global capacity to respond to outbreaks. To start Phase 3 trials in Guinea during the West Africa Ebola outbreak in 2015, it was 7 months from declaration to arrival of vaccines. This was a great achievement and set historical records at the time.

That trial evaluated the safety and efficacy of vaccines against the Zaire ebolavirus—the one responsible for the West Africa outbreak and more recently, outbreaks in the Democratic Republic of the Congo. To date, there were no licensed vaccines against the Sudan ebolavirus species responsible for the current outbreak in Uganda, thus the need for the current trial.