“We know from previous outbreaks that the D.R.C. is ready to act, but they need global support to ensure this outbreak is contained effectively,” said Dr. Jeremy Farrar, director of the Wellcome Trust.
This outbreak will be the first time a new Ebola vaccine, known as rVSV-ZEBOV, has been rolled out since it was found to be 100 percent effective in field tests in Guinea in 2016, said Dr. Seth F. Berkeley, chief executive of Gavi, the Vaccine Alliance.
Gavi has an emergency stockpile of 300,000 doses. At the moment, he said, they are stored at minus 80 degrees by the manufacturer, Merck, Sharpe & Dohme.
Because the vaccine is still unlicensed, the W.H.O. will have to approve releasing it for emergency use or the Congolese government will have to officially declare its use as part of a clinical trial, probably run by Doctors Without Borders, Dr. Berkeley explained.
“The country is requesting it, and the response is underway,” he said Friday.
The vaccine must be kept cold, but it is packed in liquid-nitrogen-cooled containers meant to withstand days of transit over rough roads in hot weather, he said.
There was another Ebola outbreak in the D.R.C. last year, also in a remote area, the province of Bas-Uélé. But before the vaccine could be rolled out, the virus was stopped by methods used in earlier outbreaks — health workers in protective gear isolating the sick and burying the dead.
Ultimately only eight infections were confirmed, and four of the victims died.
The rVSV-ZEBOV vaccine was in development for many years before the 2014 outbreak, but no one paid for clinical trials to prove it worked. The trial that proved it effective was organized only in that epidemic’s waning days, when there were just a few cases.
Several other vaccines are also in development, including candidates from Johnson & Johnson, GSK, Russia and China.