NIH Wants to Develop a Zika Vaccine, Hopes Never to Use It

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By Jeannie Baumann

The Zika virus isn’t going away, and the southern hemisphere may even experience an uptick in cases early next year, the NIH’s infectious disease chief said Sept. 28.

That’s why the National Institutes of Health continues to test an experimental vaccine that could prevent the mosquito-borne virus linked to serious birth defects, Anthony S. Fauci said during a policy forum on examining modern medicine. Fauci is director of the National Institute of Allergy and Infectious Diseases, part of the NIH. He was one of the top public faces for the Health and Human Services Department during the height of the Zika virus outbreak last year.

In the U.S. there have been fewer than 2,000 Zika-related births, including 98 live-born infants with birth defects, and eight pregnancy losses with birth defects, from 2015 to mid-September 2017. But including U.S. territories, the numbers are much higher, with 3,338 completed pregnancies and 138 live-born infants with birth defects, according to data from the Centers for Disease Control and Prevention.

Summer in South America

The outbreak, which affected 84 countries, territories, or subnational areas, appears to have cooled off, as the World Health Organization said in a recent report. But Brazil, where the first reported cases originated, is now entering into its summer months, Fauci noted.

“So I wouldn’t be surprised if we see a little bit of an uptick or more of Zika as we get into January and February,” Fauci said at the Washington Ideas forum. “I can’t predict what’s going to happen with Zika, except that it’s not going to go away.”

Scientists in the NIH’s infectious disease institute are currently testing a vaccine candidate in the continental U.S., Puerto Rico, Brazil, Peru, Costa Rica, Panama, and Mexico in a phase II/IIb clinical trial to determine if it is safe and effective in preventing Zika infection.

“We’re developing a vaccine for Zika. We hope that we never have to use it,” he said. “We hope that Zika goes down and stays down.”

Fauci told Bloomberg BNA his institute hopes to finalize study enrollment by May or June of next year. Researchers potentially could complete the trial by the end of 2020.

“The two-year follow up depends on the number of infections there are,” he said in a Sept. 28 follow up interview. “You may get your answer sooner or later—or even no answer if there are no infections. But the set up of the trial is to hopefully finish the 2,400 accrual by maybe June 2018. And you always tack on an additional two years of follow up.”

Researchers originally aimed to complete enrollment by December. But one of the largest enrollment centers was in Puerto Rico, which is still reeling from the destruction caused by Hurricane Maria.

“The hurricane set us back a bit in the accrual time, but it didn’t substantially modify anything that we’re going to do,” Fauci said.

Lessons from West Nile

The federal government has learned about vaccine development from its experience with the West Nile virus, another mosquito borne infection that first emerged in the western hemisphere in 1999. NIH scientists developed a solid vaccine candidate that tested well in the preliminary human testing known as a phase I trial.

“It was safe and it induced a good response,” Fauci said during the Sept. 27 event. “But we couldn’t find a company to partner with us to develop it because it wasn’t a winner for them at all—in fact, they would lose money.”

Now he said government scientists work on the concept development and bring the experimental vaccine to a point where it’s safer for a pharmaceutical company to manufacture the drug. “It’s a risk for them but it isn’t a profound risk,” he said. “If they did it all themselves, they’d have to invest between $750 million and a billion dollars.”

Development of that West Nile vaccine now serves as the basis for the Zika vaccine currently in phase II testing, allowing the agency to come up with a potential solution to the outbreak much more rapidly. “The real key to responding effectively to an outbreak is to develop interchangeable platforms,” Fauci, said.

The Washington Ideas forum is a collaboration between The Atlantic and the nonpartisan think tank The Aspen Institute. Some of the nation’s largest biopharmaceutical companies, including Johnson & Johnson, GlaxoSmithKline, and Eli Lilly & Co., underwrote the health and science session with Fauci.

To contact the reporter on this story: Jeannie Baumann in Washington at

To contact the editor responsible for this story: Randy Kubetin at

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More information on the Washington Ideas forum is available at

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