Rushing for a Zika Vaccine

Even genetically altered 'killer mosquitoes' may be part of the race

by Pat Barone | Updated 18 Aug 2016 at 9:17 AM

It has all the hallmarks of a futuristic movie. But this is real life, complete with a scientific chase and “killer mosquitoes.”

As local cases of transmission continue to emerge in the U.S. — and as the Olympics draws thousands of visitors to Brazil, where the first outbreak occurred — the chase for a Zika vaccine has intensified.

If there is a danger in pushing human testing of the vaccine, it comes in beginning its use, but not knowing if it works yet.

The National Institutes of Health shortened the approval process for a vaccine, while the Food and Drug Administration endorsed the release of genetically altered male Aedes aegypti mosquitoes in Florida, the prime Zika outbreak area in the United States.

The aim of the so-called “killer mosquitoes” is to pass on a fatal gene to any offspring, thereby reducing population of the insect that might carry the virus. The project still needs approval of the Florida Keys Mosquito Control before implementation, and has been tested in Brazil, Panama, and the Cayman Islands. The environmental impact is being questioned by the communities targeted for testing.

The NIH, meanwhile, has boosted the vaccine search by changing its approach, according to Dr. Meghan A. May, associate professor of microbiology and infectious diseases at the University of New England College of Osteopathic Medicine.

"The NIH has, for the first time in its history, introduced a grant submission program with a rolling deadline — meaning that a scientist can submit a proposal as soon as they can write it," May told LifeZette. "It still must be critically reviewed and competitively awarded, however."

Related: Zika's Very Real Threat to the U.S.

The usual path is to find proof-of-concept in animals (usually mice) before advancing to human testing, which can take years. In the case of Zika, a Phase I clinical trial has begun on 80 human volunteers at three sites in the U.S. by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). No proof-of-concept was used in this case. Not yet.

The rolling submission process has never been implemented before. Zika is the only topic for which the NIH will accept rolling submissions.

Timing appears key and the NIH has stepped in to shorten the wait, but results of the human testing may not be available until 2017.

The investigation centers on a vaccine developed from DNA. Testing seeks to establish the safety of the vaccine, as well as its ability to generate an immune system response.

In the rush, May does not believe safety has been compromised. "The purpose of this type of trial is simply to establish safety, and the approach being used has been demonstrated to be very safe," she said.

The virus was first identified in 1947, in the Zika forest in Uganda. It may have emerged in outbreaks through the years and gone unnoticed, due to the mild nature of the symptoms (rash, conjunctivitis, headache, and fever).

Its re-emergence was first documented in Brazil in 2015, and a recent outbreak occurred in Miami, Florida. Over 6,400 cases have been reported worldwide in 50 countries — and a child died the other day in Texas of Zika.

Severe birth defects like microcephaly and other congenital abnormalities can result when a mother is infected during pregnancy. The World Health Organization has issued warnings that Zika can also cause Guillain-Barre, a neurological condition causing temporary paralysis in adults.

If there is a danger in pushing human testing of the vaccine, it comes in establishing the vaccine's safety, and beginning its use, but not knowing if it works yet.

"My concern is that having an available vaccine whose efficacy hasn't been demonstrated may lead to a false sense of security," May said. "If a pregnant woman is immunized, decides against using insect repellent because she has been vaccinated, then becomes infected with Zika, we would have done her a disservice."

Outbreaks of viruses are not uncommon and seem to occur with regularity: swine flu in 1976; SARS in 2003; H1N1 ("bird flu") in 2009; MERS in 2012; yellow fever in 2013; Ebola in 2014.

Safe or not, the rush to test a vaccine isn’t any guarantee of a solution. Other virus outbreaks have seen similar urgency among scientists, according to Dr. Amesh A. Adalja, who teaches in the division of infectious diseases at the University of Pittsburgh School of Medicine.

Related: Zika Vaccine Trial: Too Little, Too Late? 

SARS, for example, motivated similar urgency. Part of the coronavirus family of viruses, SARS had no antiviral or vaccine precedent and killed 774 people worldwide. "Despite priority being placed on developing a SARS vaccine," Adalja told LifeZette, "we still do not have one — 13 years later."

He believes the prognosis for Zika is much better.

"Zika is a virus that has been known since the 1940s," he said. "Several other flaviviruses, the viral family to which Zika belongs, have been amenable to vaccines. Yellow Fever, Japanese Encephalitis, and dengue all have commercially available vaccines and others, such as West Nile, are in late stages of development."

Timing appears key and the NIH has stepped in to shorten the wait. Results of the human testing may not be available until 2017, however, so safety is encouraged — especially when traveling to areas where the virus is active. Increased mosquito protection as well as sexual protection for anyone interacting with someone who has traveled to an infected area is imperative.

Pat Barone, CPCC, BCC, MCC is a professional credentialed coach and author of the Own Every Bite! bodycentric re-education program for mindful and intuitive eating, who helps clients heal food addictions. 

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