Science Policy For All

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Science Policy Around the Web – November 15, 2016

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By: Sarah Hawes, PhD

Source: PHIL

Zika

Florida voters weigh in on GM mosquito releases: What are the issues?

Concern over mosquito-borne Zika virus arriving in the United States this year spurred rapid allocation of resources toward identifying solutions. Clinical trials are just beginning for a traditional, attenuated vaccine while parallel efforts include research into injecting small DNA segments to effectively vaccinate by engaging a patient’s own cells to produce harmless, Zika-like proteins. However the risk of severe birth defects in infants born to Zika infected mothers is a powerful incentive for expediency. One answer exists in the use of genetically modified (GM) mosquitos to reduce vector number by breeding them in the wild. In August, the Food and Drug Administration (FDA) agreed for the first time to release of GM mosquitoes in the U.S.

The GM mosquitos in question are almost exclusively non-biting males of the Zika vector species Aedes aegypti, modified by British biotech company Oxitec, to carry a gene that prevents their offspring from reaching sexual maturity. Oxitec has used similar techniques successfully since 2009 in the Cayman Islands, Malaysia, Brazil, and Panama. A document prepared by the FDA Center for Veterinary Medicine examines myriad concerns, and determines program risks to be negligible. It includes ecosystem reports showing lack of predators reliant on the invasive Aedes aegypti, and explains that no recognized method exists for the genome-integrated transgene to impact or spread among other species. However a small percentage of GM mosquitos survive to adulthood and could transfer modified genes (or transgene resistance) to next-generation Aedes aegypti. In addition, some fear that population reduction among one disease-carrying mosquito species will make way for another, such as Aedes albopictus, which is also capable of carrying Zika, Dengue, and Chikungunya.

On Election Day, the final word on whether or not to release Oxitec GM mosquitos was given to voters living in the proposed release-site in the small peninsula neighborhood of Key Haven, Florida, and in surrounding Monroe County. Countywide, 58 percent of voters favored release. Within Key Haven, 65 percent opposed it. Following this divide, the decision now rests with Florida Keys Mosquito Control Board. (Kelly Servick, Science Insider)

HIV Vaccine

Controversial HIV vaccine strategy gets a second chance

The first participants in a $130 million HIV vaccine study, funded primarily by the National Institute of Allergy and Infectious Diseases (NIAID) and the Bill & Melinda Gates Foundation, received injections last week in South Africa. The study is a modified repetition of a study conducted in Thailand seven years ago that used nearly three times the number of participants and reported a modest 31.2% risk reduction through vaccination. In a nation with 6 million HIV positive persons, this would still be valuable if reproduced, but there is concern that alterations in the vaccine intended to boost efficacy could have the opposite effect.

No mechanism has been found for the vaccine’s efficacy in Thailand, making it hard to improve on. In hopes of extending the duration of protection, twice the amount of an HIV surface protein will be given. A canary-pox virus carrying pieces of HIV virus common in Thailand seven years ago (targets on which to hone the body’s immunity) has instead been loaded with strains common in South Africa. Finally, a stronger immune stimulant, or “adjuvant,” is included in the injection. However, in May, a study by National Cancer Institute vaccine researcher Genoveffa Franchini found that monkeys were protected from HIV by the old but not by the new adjuvant. Franchini suggests that the new adjuvant may even leave vaccinated persons more susceptible to infection. The South Africa study leader Glenda Gray says that Franchini makes a “compelling” argument for adding a group to repeat use of the old adjuvant, if more money can be found.

The enormity of South Africa’s AIDS epidemic (18% of global cases) compels empathy for the perspective held by Gray, who said, “Someone has to put their stake in the ground and have the courage to move forward, knowing we might fail.” At the same time one would hope that the use of $130 million in HIV research funds is being fueled more by quality medical science than by desperation and action-bias. (Jon Cohen, Science Magazine)

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Written by sciencepolicyforall

November 15, 2016 at 9:45 am

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