The soonest a Zika virus vaccine could be ready would be the end of 2017, but that is only if the outbreak is still raging, a leading research official said Wednesday.
“You could have it by the end of 2017, which is rocket speed for a vaccine,” said Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, during a House hearing Wednesday. “If [the outbreak] dies down, then it winds up taking years to approve because it takes much longer to show efficacy when there are not a lot of cases.”
Zika has spread to nearly 30 countries — primarily in central and South America — and is responsible for about 50 cases in the U.S. While the virus normaly causes a mild illness, officials strongly suspect it is linked to a birth defect called microcephaly that results in babies born with smaller heads.
Tom Frieden, the head of the Centers for Disease Control and Prevention, told the House Foreign Affairs Committee that recent studies of the tissue in two babies who died of microcephaly had the Zika virus, more evidence of a link between the two.
Zika also may be linked to a condition called Guillain-Barre, a rare neurological disorder that can paralyze people.
Fauci told the committee that he is optimistic that a vaccine could be developed quickly because of the type of disease Zika resembles. Zika is like other mosquito-borne diseases such as yellow fever and dengue, which already has an approved vaccine.
The National Institutes of Health is developing a vaccine for the virus and hopes to start human testing this summer.
Normally it takes about three clinical trials to get a drug approved by the Food and Drug Administration.
After the phase I trial, which could run until the end of 2016, it could move on to Phase II, which studies the safety and effectiveness of a vaccine. Fauci said after the hearing that the trial population could balloon from hundreds of patients in phase I to thousands in Phase IIb, which explicitly studies whether the vaccine is effective.
Technically, the vaccine could be approved after Phase IIb, which could take up to eight months, skipping Phase III entirely.
The FDA could approve it for emergency purposes, Fauci said. The agency would require any manufacturer to do postmarket studies to further prove the vaccine’s safety.
Once phase I testing ends at the end of 2016, the vaccine could take four years to be approved or one year, “depending on the extent of the outbreak,” Fauci said.
Such a situation happened with the Ebola vaccine. Once human testing started, the outbreak in West Africa started to wane and there weren’t enough cases to determine the effectiveness of the vaccine.
Another problem with a Zika vaccine may be finding a manufacturer, as NIH had trouble getting a manufacturer for a West Nile vaccine due to concerns about profitability.
“I feel confident that from the indications we are currently getting from pharmaceutical companies that we won’t have these problems with Zika,” Fauci told the panel.
