Influenza A (H1N1 09): public health lessons and questions.
Influenza A (H1N1 09) has been in Australia for 2 months and, in a world that had been preparing for a potentially dramatic outbreak due to H5 avian influenza, it has challenged global and national planning assumptions, definitions of pandemic influenza and our public health interventions. It has also highlighted how much we have yet to learn about both pandemic and seasonal influenza.