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U.S. Government Starts Test of Zika Vaccine in Humans

Scientists are close behind an outbreak of a mosquito-spread disease in the U.S. with a possible fix.

The U.S. government on Tuesday for the first time tested its experimental vaccine against the Zika virus on an American volunteer.

The start of the vaccine trial, at the National Institutes of Health in Maryland, comes as officials were racing to contain an outbreak of the Zika virus in Miami, where it has already infected at least 14 people.

A vaccine could roll back the epidemic from U.S. borders, but it won’t be known for months if the government’s vaccine is safe, and it could take years longer to prove it’s effective.

The study involves a novel type of vaccination called a DNA vaccine, in which genes from the virus are shot under high pressure into a person’s arm. While easy to design, no DNA vaccine has ever reached commercialization.

A spokesperson for Anthony Fauci, director of the National Institute for Allergy and Infectious Disease, declined to comment on the trial ahead of an announcement planned for tomorrow, but another person familiar with the trial confirmed it commenced today.

According to a listing for the trial, the vaccine will be tested on upto 120 volunteers between 18 and 35. Volunteers at three sites, in Maryland, Baltimore, and Atlanta, will be drawn from the public and paid $2,000 or more for their trouble but will have to undergo a score of blood tests and office visits.

A pair of private companies, Inovio Pharmaceuticals and GeneOne Life Science, said last week they had begun tests of a different DNA vaccine against Zika, and were testing it on volunteers in Miami. “DNA vaccines are relatively new entities but they look like they’ll be effective,” says Joel Maslow, chief medical officer of GeneOne.

The continental U.S. has registered more than a thousand Zika cases already, but until last week all involved overseas travelers or their partners. Over the weekend, however, officials confirmed four cases in Miami had been acquired locally, meaning the virus has gained a foothold among mosquitoes in the city.

The outbreak was possibly set off by visitors returning from Latin America, where an epidemic has been raging since last year. If an infected person is bitten, a mosquito can then spread the disease to others.

To attempt to contain the outbreak, Florida has ramped up spraying, and the U.S. Centers for Disease Control and Prevention today issued what’s being called a historic travel advisory, advising pregnant women and their partners to avoid a square-mile zone of downtown Miami where the virus is believed to be spreading.

Containing the virus completely could be difficult. Fauci told Texas Public Radio that other areas in the southern U.S. could see outbreaks next. "I would not be surprised if we did see isolated local transmission in the southern part of Texas, particularly along the Gulf Coast," Fauci said. "I hope people take it seriously enough, especially if you’re a pregnant woman.” 

The Zika virus usually causes a mild infection, with 80 percent of cases showing no real symptoms at all. What makes the disease frightening is its link to severe birth defects, including children born with shrunken brains. That can happen if a pregnant woman gets Zika from a mosquito bite or through sex, as the virus also spreads between people that way.

“This is a very unique situation. This is the first mosquito-borne infection that actually results in congenital abnormalities if a woman gets infected when pregnant. And it’s also the first that’s sexually transmitted. So it’s got a double whammy there of very unique aspects to it," Fauci said.

With their vaccine, however, federal scientists are a demonstrating the power of biotechnology to whip up countermeasures to new threats. The vaccine they developed is a small stretch of genetic material from the virus,  which is fired into a person’s upper arm through a device that acts like a high-pressure squirt gun.

The added genes then cause the person’s body to manufacture certain harmless parts of the Zika virus, including its protein shell. That should train a person’s immune system to recognize the virus and fight it off.

However, it is still unclear if this type of vaccine can be mass-produced, a necessity if it is to protect hundreds of millions of people in the southern U.S. and throughout Latin America. Most familiar vaccines, like the one for the flu, are made of actual viruses, but inactivated or altered to make them safe.

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