Olympic health update: Zika vaccines, GMO mosquitoes, and snake oils

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With the 31st Olympic Games going on in Rio de Janeiro, the only topic trending close behind Rio 2016, Michael Phelps, Simone Biles, Aly Raisman, Katie Ledecky and the medal counts is the Zika virus that’s spreading through Brazil and popping up in other countries, including the United States.

“My concern is that Zika could already be here on the Gulf Coast,” explained Peter Hotez, Baylor College of Medicine’s dean of the National School of Tropical Medicine, in an article for JAMA Pediatrics. “It is just that nobody is looking, because none of the country and local health departments have funding to conduct active surveillance.”

Transmitted by the Aedes aegypti mosquito, Zika is notorious because it produces serious birth defects, among other complications.

“I think people don’t often appreciate how devastating Zika virus is,” said Hotez.


The gravity of the situation is fueling acceleration of research toward a Zika vaccine, which will go through early clinical testing in 80 people over the next year. Unfortunately, fear of the virus is also fueling scams, fake anti-Zika products.

Vaccine development

The National Institute of Allergy and Infectious Diseases (NIAID) has begun administering an experimental Zika DNA vaccine for a few volunteers. This is the beginning of a Phase 1 clinical trial–the category of trial that focusses first on proving safety, then on showing some efficacy–that will encompass 80 volunteers in the 18-35 year age group in the months to come. If the vaccine does stimulate the immune system in these early volunteers and proves safe, this will lead to a Phase 2 trial, a march larger investigation, and that will begin early next year. Generally, such larger studies take longer, but NIAID will attempt to accelerate the work.

“If we get a good immune response [from the vaccine] and there are no safety red flags…we should know if it’s OK to move on to Phase 2,” said Dr. Anthony Fauci, the NIAID director in a news conference on August 3.


But don’t think this means there will be a vaccine a year, or even two. According to Fauci, it could be several years before a vaccine is ready, and enough is produced, to protect entire populations. Initially, vaccine administration would target women of reproductive age. They’d be immunized prior to becoming pregnant.

The reason for targeting young women is that, thus far, the most dire complication of Zika infection is a birth defect–microcephally. Fauci noted, however that some countries may decide to vaccinate all children early on, similar to what was as was done following release of an approved vaccine against rubella. As with Zika, the main concerns surrounding rubella involve infection of pregnant women, since rubella also causes birth defects in pregnancy.

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High-tech mosquitoes

Another solution in the works is to go after mosquito populations with genetically modified male A. aegypti mosquitoes. A field trial of this strategy was approved recently. Only females bite, and so modified males can serve as literal biological weapons. They can deliver genetic payload into the population and large numbers can be released without risk that they will bite people. The GM mosquitoes compete with wild type males as mates for wild females, but the offspring of the GM mosquitoes die before they mature. Since the generational time for these insects is very short, in just one season, the size of the population can be reduced significantly.


A little further on the horizon is the possibility of an A. aegilti gene drive. This can be achieved using CRISPR genome editing systems, resulting in male mosquitoes whose altered trait not only transmits to offspring, but in the offspring copies itself from form the paternally received chromosome to the homologous chromosome received from the mother. This results in permanent penetration of the new trait through the population, and the rather than causing offspring to die, the trait can be something like immune resistance to the Zika virus. A similar system is already in development for another kind of mosquito, Anopheles, the genus that carries the malaria parasite.

Snake oil

As vaccine work proceeds carefully and following scientific protocol, the peddlers of pseudoscience have not hesitated to capitalize on growing public fear of the virus and its insect vectors. The following products were selling well, mostly in online settings–until recently when New York State Attorney General Eric Schneiderman named their marketers  for prosecution on counts of fraud:

  • Ultrasonic Wildheart Outdoors Natural Mosquito Repellent Bracelet
  • The Kenza High Quality Zika Mosquito Repellent
  • Smiley Patch
  • The STAR Ultrasonic Pest Repeller.

In addition to giving unsuspecting consumers a false sense of security, some of the products have the potential for direct harm. Ultrasonic devices, for instance, have been demonstrated, not to repel mosquitoes, but possibly to attract them., Schneiderman noted in an interview. He also said that some of the worse devices were targeted for use in children.


Schneiderman advised the public to use only insect repellants that are registered with the United States Environmental Protection Agency. Short of that, and until a vaccine is approved and available, common sense measures constitute the best strategy. And the number one common sense measure could be caution when confronted with online marketing.

David Warmflash is an astrobiologist, physician and science writer. Follow @CosmicEvolution to read what he is saying on Twitter.

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