KAMPALA – Ugandan officials are preparing to deploy a trial vaccine as part of efforts to stem an outbreak of Ebola in the capital, Kampala, a top health official said Sunday.

A range of scientists are developing research protocols relating to the planned deployment of more than 2,000 doses of a candidate vaccine against the Sudan strain of Ebola, said Pontiano Kaleebu, executive director of Uganda Virus Research Institute.

“Protocol is being accelerated” to get all the necessary regulatory approvals, he said. “This vaccine is not yet licensed.”

The World Health Organization said in a statement that its support to Uganda’s response to the outbreak includes access to 2,160 doses of trial vaccine.

“Research teams have been deployed to the field to work along with the surveillance teams as approvals are awaited,” the WHO statement said.

The candidate vaccine as well as candidate treatments are being made available through clinical trial protocols to further test for efficacy and safety, it said.

The vaccine maker wasn’t immediately known. There are no approved vaccines for the Sudan strain of Ebola that killed a nurse employed at Kampala’s main referral hospital. The man died on Wednesday and authorities declared an outbreak the next day. Officials are still investigating the source of the outbreak, and there has been no other confirmed case.

Uganda has had access to candidate vaccine doses since the end of an Ebola outbreak in September 2022 that killed at least 55 people. Ugandan officials ran out of time to begin a vaccine study when that outbreak, in central Uganda, was declared over about four months later, Kaleebu said.

A trial vaccine known as rVSV-ZEBOV, used to vaccinate 3,000 people at risk of infection during an outbreak of the Zaire strain of Ebola in eastern Congo between 2018 and 2020, proved effective in containing the spread of the disease there.

Uganda has had multiple Ebola outbreaks, including one in 2000 that killed hundreds. The 2014-16 Ebola outbreak in West Africa killed more than 11,000 people, the disease’s largest death toll.

Tracing contacts is also key to stemming the spread of Ebola, which manifests as a viral hemorrhagic fever.

At least 44 contacts of the victim in the current outbreak have been identified, including 30 health workers and patients, according to Uganda’s Ministry of Health.

Confirmation of Ebola in Uganda is the latest in a series of outbreaks of viral hemorrhagic fevers in the east African region. Tanzania declared an outbreak of the Ebola-like Marburg disease earlier this month, while in December Rwanda announced that its own outbreak of Marburg was over. The ongoing Marburg outbreak in northern Tanzania’s Kagera region has killed at least two people, according to local health authorities.

Kampala’s outbreak could prove difficult to respond to, because the city has a highly mobile population of about 4 million. The nurse who died had sought treatment at a hospital just outside Kampala and later traveled to Mbale, in the country’s east, where he was admitted to a public hospital. Health authorities said the man also sought the services of a traditional healer.

Ebola is spread by contact with bodily fluids of an infected person or contaminated materials. Symptoms include fever, vomiting, diarrhea, muscle pain and at times internal and external bleeding.

Scientists don’t know the natural reservoir of Ebola, but they suspect the first person infected in an outbreak acquired the virus through contact with an infected animal or eating its raw meat.

Ebola was discovered in 1976 in two simultaneous outbreaks in South Sudan and Congo, where it occurred in a village near the Ebola River, after which the disease is named.