Second Ebola vaccine set to be used soon in Democratic Republic of the Congo

The Democratic Republic of the Congo will begin using a second Ebola vaccine as early as next week, the company developing the experimental product, Johnson & Johnson, said Thursday. J&J announced it is donating enough of the product to vaccinate up to 500,000 people.

The vaccine will be used as part of a clinical trial, but the aim is as much to help extinguish the long-running outbreak in the country’s northeast as it is to gather data on the effectiveness of the vaccine, which does not yet have a brand name.

“We are very excited to be able to contribute,” Dr. Johan van Hoof, global head of Janssen Infectious Diseases and Vaccines, J&J’s vaccines division, told STAT. “We see this as a significant milestone having worked so long on this that this is now going to be used.”

In recent weeks the outbreak has appeared to be waning, with fewer cases in October than any month since September 2018. Should the outbreak end in the next couple of months, it’s not clear whether the trial will be able to determine if the vaccine is as protective as earlier studies would suggest. The company has tested the vaccine in primates — a good model for human infection — and has monitored both how high antibody levels rose and how long they remained elevated in people who were vaccinated in Phase 2 trials.

“It’s very difficult to predict either way whether this will allow us to assess effectiveness for this particular outbreak,” van Hoof acknowledged, though he noted the outbreak is unpredictable and it’s far too soon to conclude it may soon end.

“At the end of the day it’s only in this type of setting that we will able to assess effectiveness one day,” he said. “And hopefully we can do it now. But that’s not sure.”

The Ebola outbreak, in the provinces of North Kivu and Ituri, was officially declared underway at the beginning of August 2018. It is the second-largest outbreak on record, with at least 3,269 infections and nearly 2,200 deaths.

Another experimental vaccine, made by Merck, has been used virtually since the start of the outbreak. As of Wednesday more than 245,000 people have been vaccinated.

The Merck vaccine, which is given in one dose and which mounts a rapid immune response, has been used in a ring vaccination strategy. People who have been in contact with infected people — and the contacts of those contacts — are offered a chance to be vaccinated, as are health care workers and other frontline workers.

The J&J vaccine is given in two doses, administered 56 days apart. While it is thought the initial dose will offer some protection, full protection from the vaccine will take more than two months to develop after the first vaccination. People will be vaccinated en masse.

The plan is to use the vaccine in places near the outbreak, but not where transmission is currently occurring. Van Hoof said the government of DRC has decided to begin vaccinating in Goma, a large city to the south of the outbreak zone. There have twice been cases in or near Goma, but on both occasions transmission was stopped.

It has long been feared that Goma — which is a transportation hub and a gateway to other countries in Eastern Africa — could become engulfed in the outbreak. The goal of vaccinating people there is to create a wall of immunity to prevent the virus from taking hold. Health workers in Goma, as well as traders who cross daily from Goma into Rwanda, will be among the first people offered the vaccine.

While J&J has indicated it is willing to donate enough vaccine to protect 500,000 people, it’s not certain that many people will be vaccinated.

The trial is being conducted by researchers from DRC’s National Institute for Biomedical Research and its Ministry of Health, along with scientists from the London School of Hygiene and Tropical Medicine and Doctors Without Borders. It is being funded by the Coalition for Epidemic Preparedness Innovations — known as CEPI — the European Union, Britain’s Department for International Development, the Wellcome Trust, and the Paul G. Allen Family Foundation.

Van Hoof said J&J will file a licensure application with European regulatory authorities before the end of this year. It is also filing, on a rolling basis, with the Food and Drug Administration; he said discussions with the FDA are still underway on how much more data would be required.