The Serum Institute of India plans to manufacture 20,000 to 30,000 doses of an experimental Ebola vaccine by the end of November for use in trials against an outbreak in Uganda, its developers and a company source said.

The response to Uganda's outbreak has been blunted by the absence of a proven vaccine against the Sudan strain of the virus.

There have been 54 confirmed cases and 19 deaths since last month and the first case in the capital, Kampala, was recorded last week. But health authorities believe the actual numbers could be higher.

Vaccines against the more common Zaire strain of Ebola have proven highly effective during recent outbreaks in neighbouring Democratic Republic of Congo.

Oxford University, which developed a COVID-19 vaccine with AstraZeneca, has an Ebola vaccine that has been shown to induce an immune response to both the Sudan and Zaire strains in Phase 1 trials.

Its developers said they were working with the Serum Institute to manufacture doses that could be deployed in Uganda as part of a clinical trial once the authorities there gave regulatory approval.

"We are hoping to have a large number of doses, approximately 20,000 to 30,000 or more by mid-to-end of November," Teresa Lambe, the chief scientific investigator on Oxford's Ebola vaccine, told Reuters.

A source at the Serum Institute, the world's biggest vaccine maker and part of a conglomerate run by Indian billionaire Cyrus Poonawalla, confirmed this information. The source said the Ebola vaccine doses would be supplied free of cost.

'PLAYING CATCH UP'

Uganda's Information Minister Chris Baryomunsi said he did not have any information on a vaccine rollout.

World Health Organization (WHO) chief Tedros Adhanom Ghebreyesus said last week that clinical trials of two vaccines could begin in the coming weeks pending Ugandan government approvals, without naming the vaccines.

There are at least six vaccines in development for the Sudan strain, including three with Phase 1 data, according to WHO.

One of those was developed by the Sabin Vaccine Institute in Washington, D.C. A Sabin spokesperson said the institute believed its vaccine was "farthest along in the pipeline" and that it was working with WHO and other organisations about how it can help respond to the outbreak.

The Oxford researchers voiced frustration that their vaccine was not ready to be rolled out when the outbreak hit, saying governments around the world had not made investing in vaccines enough of a priority in the wake of the COVID-19 pandemic.

The vaccine has been in development for several years but its progress through clinical trials has been slowed by funding shortfalls, they said.

"With better investment the world could easily have ready-made vaccines sitting in vials for this and a number of other diseases," said Sandy Douglas, an associate professor at Oxford.

"We're spending a couple of months now playing catch up on work that could have been done ahead of time."

(Additional reporting by Elias Biryabarema in Kampala; Editing by Andrew Cawthorne)