Sudan Ebolavirus Outbreak Continues Without Approved Vaccines

West Africa continues to bear the scars of the Ebola outbreak that occurred a decade ago. From 2014 to 2016, Sierra Leone, Guinea, and Liberia faced the largest Ebola outbreak since the virus was first discovered in 1976.

This Ebola outbreak resulted in over 28,000 cases and 11,000 related fatalities.

As of April 2025, more than 30 Ebolavirus disease outbreaks have been reported.

The good news is that vaccines against Ebolavirus, the pathogen responsible for those outbreaks, have since been licensed, and stockpiles have been developed.

"All Ebola outbreaks that have occurred since we had a stockpile were quickly stopped – thanks to the vaccines and rapid other response measures," says Allyson Russell, an epidemiologist and senior programme manager in Gavi's High Impact Outbreaks team, in a GAVI news article published on April 15, 2025.

However, these Ebola vaccines aren't effective against the other three orthoebolaviruses that cause severe disease, including the Sudan virus outbreak in the Republic of Uganda.

Uganda's Ministry of Health declared its eighth Sudan Ebolavirus outbreak in January 2025. Since then, about 14 cases, including four related fatalities, have been reported.

To alert the international community, the U.S. government recently updated a Level 2 Travel Health Advisory.

On March 12, 2025, the Centers for Disease Control and Prevention confirmed a Sudan virus outbreak in the districts of Kampala, Wakiso, Jinja, Mbale, Kyegegwa, Kabarole, and Ntoroko.

Still, the unpredictability and rapid progression of Ebola outbreaks make testing vaccine efficacy challenging.

As of April 19, 2025, no vaccines have been approved to protect people against the Sudan Ebola virus. However, candidate vaccines are being tested in the Solidarity Against Ebola human clinical studies in Africa.