The experiments that started the whole controversy around Gain of Function research involved passing H5N1 through ferrets, in order to “gain the function” of being transmissible between mammals. Unfortunately, intensive agriculture practices mean that we may not even need to do GoF research in order to force a virus through many animal hosts with weakened immune systems that are in close proximity to humans.
Highly pathogenic avian influenza A(H5N1) virus infection in farmed minks, Spain, October 2022
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The experiments that started the whole controversy around Gain of Function research involved passing H5N1 through ferrets, in order to “gain the function” of being transmissible between mammals. Unfortunately, intensive agriculture practices mean that we may not even need to do GoF research in order to force a virus through many animal hosts with weakened immune systems that are in close proximity to humans.