Human Trials Begin for Vaccine Against Zika-Carrying Aedes Aegypti Mosquito

Solutions to Miami's slow-simmering Zika virus crisis have included the following: fumigating the city with possibly dangerous pesticides; releasing bats into the sky, Hunter S. Thompson-style; desperately avoiding Zika "hot zones"; and genetically modifying the Zika-carrying Aedes aegypti mosquito so they all die.

But those Hail Mary-esque decisions ignore an obvious fix: Why not just prevent any diseases from transmitting through that mosquito's bite? The idea is apparently so simple that human trials began last Tuesday for a vaccine that would trigger an immune response to the saliva from the Aedes aegypti.

According to the National Institutes of Health (NIH), a vaccine to make humans taste gross to mosquitoes might honestly be humanity's quickest answer to the host of tropical diseases buzzing across South America, the Caribbean, and the Southern United States. Only one genus — the Aedes mosquito — carries dengue fever, Chikungunya, and Zika and has spread those diseases all over the Western Hemisphere.

"A single vaccine capable of protecting against the scourge of mosquito-borne diseases is a novel concept that, if proven successful, would be a monumental public health advance," said Dr. Anthony S. Fauci, who runs the NIH's National Institute of Allergy and Infectious Diseases.

Last year, Dr. Tom Frieden, the director of the U.S. Centers for Disease Control and Prevention, warned in an interview with the Atlantic's editor in chief, Jeffrey Goldberg, that Zika would become "endemic" in the United States — fated to return during mosquito season every summer — unless a vaccine for humans can be invented. (Floridians contracted 1,072 cases of Zika while traveling in 2016 and 274 cases from American mosquitoes.) Any sort of legal vaccine is still years away: Most Zika-specific vaccines are still just being tested on monkeys, and even human trials can stretch over multiple years.

But the London pharmaceutical company SEEK says it might have found a way to fix many of the world's tropical-disease problems through a single shot. According to a news release the NIH published Tuesday, SEEK's vaccine, called AGS-v, works by teaching the human body to reject mosquito saliva.

"Unlike other vaccines targeting specific mosquito-borne diseases, the AGS-v candidate is designed to trigger an immune response to mosquito saliva rather than to a specific virus or parasite carried by mosquitoes," the NIH says. "The test vaccine contains four synthetic proteins from mosquito salivary glands. The proteins are designed to induce antibodies in a vaccinated individual and to cause a modified allergic response that can prevent infection when a person is bitten by a disease-carrying mosquito."

The Phase 1 clinical trial — which will be conducted in Bethesda, Maryland, right outside Washington, D.C. — is expected to enroll 60 people aged 18 to 50. One group will receive two doses of the vaccine, 21 days apart, while another group will receive the vaccine and an "adjuvant," which is a booster that helps promote a vaccine's efficacy.

Then the participants will be exposed to biting female mosquitoes, thought the bugs won't carry any diseases.

"Each participant also will return to the Clinical Center approximately 21 days after completing the vaccination schedule to undergo a controlled exposure to biting mosquitoes," the NIH says. "The mosquitoes will not be carrying viruses or parasites, so the participants are not at risk of becoming infected with a mosquito-borne disease. Five to 10 female Aedes aegypti mosquitoes from the insectary in NIAID’s Laboratory of Malaria and Vector Research will be put in a feeding device that will be placed on each participant’s arm for 20 minutes. The mosquitoes will bite the participants' arms through the netting on the feeding devices."

Doctors will then test to see if the participants' immune responses react to the mosquito saliva.

Though the news is quite heartening, especially for pregnant South Floridians or folks with a financial stake in Miami's tourism economy, it'll likely be a long time before any real Aedes vaccine comes to market: This first study isn't expected to end until next year.

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