Ebola is highly contagious and lethal. It spreads across borders, as seen in the May 2026 outbreaks in the Democratic Republic of the Congo and Uganda. However, that does not automatically classify it as a pandemic.
On May 17, 2026, the World Health Organization declared a public health emergency of international concern after reports of an Ebola outbreak caused by the Bundibugyo virus surfaced in the Democratic Republic of the Congo and Uganda.
But the WHO stated that the outbreak did "not meet the criteria of a pandemic emergency."
This development follows the hantavirus outbreak on the MV Hondius and β perhaps notably β as the WHO convenes for its 79th General Assembly (May 18-23, 2026).
Key facts about Ebola:
Ebola damages blood vessels and leads to severe internal bleeding
It spreads from animals to humans and between humans through close contact with blood, organs, secretions, and other bodily fluids
Some strains of Ebola can be prevented with vaccines and treated with medications
First identified in 1976, the largest known outbreak from 2014 to 2016 spread across Central Africa, resulting in 10,000 deaths
Ebola continues to pose a persistent challenge for people and authorities in affected areas. Vaccine development may help reduce the burden.
Ebola: What to know after WHO declares health emergency
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Most Ebola outbreaks have been caused by the Zaire strain of the Ebola virus (Zaire ebolavirus) and the Sudan strain (Sudan ebolavirus).
During recent outbreaks with high numbers of infections, researchers have used these real-world situations to test vaccines under development.
What have been the most severe Ebola outbreaks?
The largest Ebola outbreak occurred four decades after the disease was first identified.
Between 2014 and 2016, Ebola spread from the Democratic Republic of the Congo (DRC) in Central Africa to Liberia, Guinea, and Sierra Leone in West Africa. There were over 28,600 infections and 10,000 deaths.
From 2018 to 2020, Ebola again spread from the DRC to Uganda. Additional outbreaks have occurred in Gabon, South Africa, Ivory Coast, Nigeria, Mali, and Senegal, killing at least 2,000 people.
What is the difference between the Ebola virus and Sudan virus?
Ebola was discovered near the Ebola River during two simultaneous outbreaks in 1976 β in Zaire, now the DRC, and South Sudan.
Ebola virus disease (EVD), named after the river, is the deadliest form of the virus. It has a survival rate of 10% of cases.
Sudan virus disease (SVD) causes death in about 50% of cases.
The third most common variant in Africa is the Bundibugyo virus, discovered in 2007.
Symptoms are similar: fever, nausea, weakness, loss of appetite, and unexplained bleeding. Chest pain can occur with SVD, but is less common with EVD.
How is Ebola virus treated?
If caught early, hospital treatment with oral and intravenous fluids and medications can help reduce the risk of death.
One such medication is Ebanga, an antibody-based drug that prevents the virus from entering cells, thereby slowing its spread through the body.
A second drug is Inmazeb, a combination of three antibodies.
In both cases, patients should avoid using live virus vaccines at the same time.
The World Health Organization (WHO) advises against treating people at home, especially without professional healthcare assistance. The virus is highly contagious, and other household members are likely to become ill.
Other treatments include blood transfusions, medications to manage symptoms β such as pain, nausea, vomiting, and diarrhea β or co-existing illnesses like malaria.
Are there vaccines against Ebola?
Ervebo has been approved for use in the US and European Union.
It can be used to protect adults and children against EVD. However, regulations vary β Ervebo is approved for use in Europe from age 1, while the US has only approved it for people aged 18 and older.
Drug and vaccine approvals by the leading US and European agencies (FDA and EMA, respectively) are considered the global standard, so Ervebo may also be used in Africa.
It is also necessary for people traveling to Ebola-affected regions to get vaccinated before their trip.
What is Ervebo?
Ervebo is a live-attenuated vaccine.
This means it contains a weakened protein from EVD, which is not strong enough to cause a full infection but is sufficient to trigger an immune response.
Then, if the vaccinated person later encounters the actual virus, the body knows how to respond and defend itself against the viral attack.
In February 2025, the International AIDS Vaccine Initiative, Uganda's Health Ministry, Makerere University in Kampala, and the WHO launched a trial for a candidate vaccine against SVD.
It was the first trial conducted during an active outbreak β Uganda's sixth outbreak of the Sudan strain of the virus.
The Sudan vaccine is designed similarly to Ervebo. It is considered one of the most promising vaccine types against Ebola and other so-called filoviruses, including Marburg.
Edited by: Matthew Ward Agius
This article was originally published on February 6, 2025, and was updated to include a new outbreak in the Democratic Republic of the Congo and Uganda on May 18, 2026.