A version of this editorial appears in the February 2013 issue of Nature Medicine.
Last January, scientists voluntarily imposed a pause on research that could lead to the generation of highly pathogenic avian influenza viruses with increased transmissibility to mammals. Now, new restrictions currently under debate further risk stalling progress in avian flu research.
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In late 2011, a firestorm erupted around two papers under peer review on highly pathogenic avian influenza (HPAI) H5N1 viruses. Both identified mutations that would permit airborne transmission of the viruses to ferrets. Although the viruses were not highly pathogenic in the ferrets, the papers sparked concerns that the mutant H5N1 viruses might have pandemic potential.
The concerns are not unwarranted given the history of H5N1 infections. The case fatality rate due to H5N1 in humans exceeds 50%, yet only 610 infections have been recorded since 2003, in part because of its low capacity for human-to-human transmission. However, there is fear that avian influenza could acquire the mutations necessary to rapidly transmit among humans, similar to seasonal influenza. Therefore, a better understanding of the mutations necessary to facilitate transmission of H5N1 in mammals and their effects on the fitness of the virus is considered by many to be crucial in developing countermeasures in the event of an avian flu pandemic.