Oxitec makes no claim that their GMO mosquitoes can fight Zika. Doing so might put the product under human drug laws which require actual testing along with lots of other disclosure they don’t want to get into. The real product description of the GMO mosquito is this: “OX513A males mate with local wild-type, non-GE female Aedes aegypti in a population so that the resulting progeny carry a copy of the #OX513 rDNA construct and produce at least a 2-fold increase in mortality of these #OX513 rDNA construct-bearing progeny relative to local non-GE progeny before they reach functional adulthood.”
The only product claim is that their mosquitoes have twice the chance of dying before adulthood as unmodified mosquitoes in the wild. Now that may sound very dramatic, but they don’t reveal how many would die before adulthood in the wild. If only 1% would die on their own, then a “2-fold increase in mortality” means only 2% would die.
Oxitec cannot claim any effectiveness against Dengue, Zika, or any other human disease because this would take the product out of the Center for Veterinary Medicine and into the human drug division of the FDA. Oxitec has skirted a whole slew of disclosures, tests, and regulations by portraying their product as a “drug for animals.”