The results of two, as yet unpublished, investigations of laboratory-induced genetic changes in avian influenza A(H5N1) viruses have been reported to have found that a surprisingly few number of changes make the viruses transmissible between ferrets, the most commonly used model for the way influenza behaves in humans. The possibility that this could have resulted in the development in laboratories of A(H5N1) influenza viruses transmissible between humans has caused concern for public safety and generated unusually high levels of debate in the scientific community. This report summarises and explains the complex public health and scientific issues around these developments including the positive and negative aspects of some of the responses that have been proposed internationally.

Following the emergence of swine influenza A(H3N2) variant (v) viruses with sporadic human infections in North America, the Community Network of Reference Laboratories (CNRL) and the Animal Health and Veterinary Laboratories Agency completed an exercise to assess the CNRL’s capability to detect novel reassortant and circulating triple reassortant swine viruses (TRA) in humans.

Following the emergence of swine influenza A(H3N2) variant (v) viruses with sporadic human infections in North America, ECDC and the Community Network of Reference Laboratories (CNRL) disseminated a questionnaire to explore the RT-PCR capability of influenza reference laboratories in EU/EEA countries to detect A(H3N2)v viruses in their day-to-day diagnostics and to subtype them as swine-origin variant viruses.