An experimental Ebola vaccine from Johnson & Johnson, boosted by a second immunization shot from biotechnology company Bavarian Nordic, generated a powerful immune response among volunteers in its first tests in humans.
The novel approach may provide durable protection against the deadly virus that swept across the West African nations of Liberia, Sierra Leone and Guinea in 2014, sickening almost 29,000 people and killing more than 11,000. The study, published in the Journal of the American Medical Association, found that 100 percent of people getting the one-two combination were still producing antibodies against the virus eight months later, a promising result for researchers looking for a vaccine against the infection that’s still generating clusters of disease. The World Health Organization declared an end to the public health emergency last month.
The companies have rushed to produce about 2 million doses, according to J&J. They face a challenge, however, in trying to study the vaccine’s real-world effectiveness since Ebola isn’t currently circulating in large numbers. They are instead working to confirm its safety and further test the immune system’s response in preparation for another outbreak or emergency, should one appear, said Paul Stoffels, J&J’s chief scientific officer.
“If there is a large epidemic, we should be able to use it to study the efficacy,” Stoffels said. “Hopefully we will never need it, but if it is a problem, we’ll be ready to step in.”
The initial results don’t look significantly different from studies of potential rivals, including Merck & Co.’s experimental Ebola vaccine, said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which helped discover J&J’s vaccine, called AdVac. The difference with the new approach is the first shot is used to prime the immune system and the second boosts the response, perhaps creating a longer benefit, he said.
“This has the potential for greater durability, though we don’t know that yet,” Fauci said. The immune responses from the different approaches will likely be compared once more patients have receive the prime-boost vaccine, he said. “If it is comparable or better, that would be a good reason for this one to proceed in development. There is always room for more than one vaccine.”
The study involved 87 volunteers, who received either J&J’s AdVac or Bavarian Nordic’s MVA-BN booster, followed by the other, or a placebo. The J&J immunization, followed by the Bavarian Nordic shot, proved the most potent. Eight months after the vaccine, all the patients who received it were still producing antibodies against Ebola, and the majority were making immune system T-cells that could kill ebola-infected cells to prevent them from replicating. Injection site pain was the most common side effect, with fever occurring in about 5 percent of volunteers.
The research was funded in part by the U.S. National Institutes of Health and grants from a European consortium that includes the London School of Hygiene & Tropical Medicine, the University of Oxford and the French National Institute of Health and Medical Research.
Stoffels said the vaccine’s development was a test of the pharmaceutical industry, and one he was proud to take on. The company has already spent in excess of $100 million on its Ebola efforts, and is testing the vaccine in more than 1,400 people.
“More than one vaccine option was necessary because the outbreak was so big and getting out of hand,” he said. “When we stepped into this, it wasn’t to get a return on investment. There was a crisis and we had the technology.”