ment, virulence, and transmissibility. H5N1 variants provide an opportunity to study all of these phenomena. Breakthroughs in these areas of scientific understanding could rapidly lead to more effective and more easily produced countermeasures to an influenza pandemic.
As knowledge of the molecular pathology of influenza expands, it should become possible to predict the threat posed by a particular strain by analyzing key sequences in its genome. While there has been one probable case of human-to-human transmission (ProMED-mail, 2004e) to date, the fact that H5N1 has not yet accomplished infectious human-to-human transmission begs the question, “why not?” Risk assessment tools based on influenza viral genomics may one day provide an answer—and perhaps prevent the unnecessary culling of poultry or livestock following outbreaks of avian influenza.
Limited supplies of vaccine could go further if their antigen content could be adjusted to provide the lowest effective dose to each recipient, and if they could be safely made more effective with an adjuvant. Several participants suggested the need for the United States and Europe to view this problem as a joint effort and work together to assure that the entire set of needs for improving influenza vaccines is addressed and shared.
An atmosphere of 11th-hour urgency surrounded many of the workshop presentations and participant discussions. The potential for catastrophe is immense, but that potential has been evident, and largely ignored, since 1918. The power of vaccines to prevent influenza is well proven, but the capacity to produce them—as recent events confirm—is limited so as to put them out of reach of the vast majority of the global population. If the initial cases of an emerging human influenza strain are detected, and if antiviral drugs were quickly administered to the close contacts of index cases, transmission could be stifled—but those are big “ifs” in a world where early reporting of influenza carries dire economic consequences and where nations are expected to nationalize stockpiles and production of antiviral drugs and vaccines in response to a threatened pandemic. What should be done to prevent the loss of millions of lives, and the evidence for doing it, is quite clear. What is missing—as evidenced by the clarion calls of