A top researcher with the National Institutes of Health said Monday that a vaccine for the Zika virus should be available in a year or two.
Mark Challberg, the flavivirus program officer for the National Institute of Allergy and Infectious Diseases, said government research has led to promising clinical trials on shots to protect people from the mosquito-transmitted virus known for causing severe birth defects.
Challberg described it as a redemptive effort following the Ebola virus outbreak in West Africa that killed more than 11,000 people.
“I think the U.S. government was somewhat embarrassed by our response to the Ebola outbreak,” Challberg said. “There was a real lack of coordination in what was happening between the various U.S. government agencies during that time, at least at the outset. So when the Zika virus came on board, there was a concerted effort to try to have a coordinated U.S. government response.”
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Challberg spoke Monday morning at a Kansas City Life Sciences Institute symposium on “Preventing the Next Pandemic.”
He said there are at least 20 Zika vaccines in various stages of development worldwide, but two of the most advanced are coming out of direct investment and research by the U.S. government.
One was a joint effort between the U.S. Department of Defense and U.S. Department of Health and Human Services. The other was developed by NIH’s Vaccine Research Center.
“The government really has done pretty much everything,” Challberg said of the early-stage research.
Now the government agencies are starting to turn their work over to pharmaceutical companies to continue with more advanced trials and possibly scale up production.
The U.S. Army announced late last year it intended to grant an exclusive patent license for the defense department vaccine to French-based Sanofi Pasteur. The company would pay the military a royalty fee if the shot successfully goes to market. The deal has raised concerns that Sanofi might try to jack up the price of the vaccine, but other options are also in the pipeline.
In March, Challberg’s agency started Phase II trials with its vaccine, enrolling thousands of participants in Houston, Miami and Puerto Rico and several countries south of the United States.
Challberg said the various Zika vaccines in development reflect different strategies for provoking an immune response: some use a whole, inactivated virus; some use a live, attenuated virus in which the virulence of the pathogen has been reduced and some use genetically engineered DNA.
The approaches have different advantages and disadvantages when it comes to safety and effectiveness. Challberg said he could envision a future with different Zika vaccines for different populations: some geared to stop an acute outbreak, some geared at travelers to regions where mosquitoes are spreading the illness and some geared at residents of those regions.
The mosquitoes that can carry the Zika virus have been found in eastern Kansas, but so far the cases in Kansas and Missouri have all been travel-related. The only documented instances of mosquito-borne Zika in the continental U.S. were in Florida and Texas.
A study of almost 1,500 pregnant women with Zika in the continental United States found that it caused birth defects in about 5 percent of cases. Challberg said higher rates have been observed in other countries and scientists are still learning more about other possible effects of the virus, which can be spread through sexual contact.
Recent studies have shown it also can damage the testes of infected mice.
“It’s not yet clear whether this is a problem in humans,” Challberg said.