Scientists say they’re making serious headway on an Ebola vaccine, but after tens of millions of dollars and years of effort, major gaps must be closed before they can crown an antidote.
Dr. Anthony Fauci, who leads infectious disease research for the National Institutes of Health, said scientists are testing two particularly promising candidates, as back-to-back outbreaks this year in the Democratic Republic of Congo have underscored the lingering threat of the deadly virus.
The World Health Organization is vaccinating contacts of infected people in the country with an experimental shot that proved effective in Guinea three years ago.
A global research coalition is testing the vaccine, known as VSV-ZEBOV, against another promising candidate and a placebo in a 5,000-person trial in West Africa, where a young boy’s contact with infected bats sparked a massive outbreak five years ago.
The study is continuing, and participants will be tracked over time. But results of the controlled analysis, combined with studies on animals and use of vaccine candidates in live outbreaks, should provide enough data to satisfy regulatory authorities before another five years breezes by, Dr. Fauci told The Washington Times.
“I think we’re on the pathway to licensure of a Ebola vaccine,” he said, although he declined to predict when, exactly, scientists will declare victory.
NIH started its pursuit of an Ebola vaccine about a decade ago, when the government feared the virus and other bio-agents could be used for terrorism by rogue actors, Dr. Fauci said.
The Ebola outbreak that killed more than 11,000 in West Africa accelerated those efforts — NIH spent more than $35 million on Ebola vaccines in both 2016 and 2017 — yet researchers are still trying to understand how the trial vaccines affect children, pregnant women and people with weak immune systems, U.S. scientists and fellow researchers say in a new progress report for the Lancet, a medical journal.
Global responders shied away from giving trial vaccines to young children or other vulnerable populations during the massive West African outbreak of 2013-2016, even though one in five people infected were under 16.
The vaccines were still rather new, so scientists didn’t want to introduce harm into otherwise healthy people.
“It’s the interesting reality of vaccine trials. When you’re giving the vaccine to people who are normal people you’re trying to protect — as opposed to someone who is sick and you’re giving a drug to — safety is very important,” Dr. Fauci said.
The vaccine campaigns in the Congo should shed some light on how the shots affect children. Responders weighed the risks versus benefits and decided to give the VSV-ZEBOV vaccine, which is suppled by Merck and stockpiled by the WHO, to children as young as 1 year old.
The consortium in West Africa, known as PREVAC, also is giving trial vaccines to children 1 and older in its controlled study, as the global community gets more comfortable with the shots.
Besides vaccines’ impact on vulnerable populations, scientists are still trying to pinpoint which ones offer long-lasting protection.
“Durability is critical,” Dr. Fauci said. “If you want to get out of the emergency mode and say, ’For sure, sooner or later there’s going to be an other outbreak in the DRC,’ you would want to vaccinate the health workers who will be in the trenches.”
The second candidate being tested in West Africa, known in lab-speak as a Ad26.ZEBOV with an MVA-BN-Filo boost, shows promise.
Developed by Janssen Vaccines & Prevention and Bavarian Nordic, the two-pronged treatment has been shown to produce an immunity response for at least 360 days.
• Tom Howell Jr. can be reached at thowell@washingtontimes.com.
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