Universal influenza vaccination has been proposed as one strategy to improve vaccination coverage and disease prevention. In October 2005, influenza and vaccination experts, public health practitioners, representatives from medical professional societies, influenza vaccine manufacturers, and managed care organizations met to assess whether current data were sufficient to support an expansion of universal influenza vaccination and to define information gaps and potential barriers to implementation. Presenters at the meeting documented the substantial burden of influenza disease among all age groups, the major role of children in transmission, and the effectiveness of vaccine, especially in healthy children and adults. Observational studies and a mathematical model suggested that indirect protection, or "herd immunity," resulting from vaccination of school-age children would substantially reduce the incidence of disease in other age groups. Economic analyses generally showed that vaccination of healthy children and adults is cost-effective and is sensitive to vaccine cost, population group, and season. Influenza vaccination received annually over several years is safe and effective, but data on long-term use are limited. Challenges to expanded recommendations include maintenance of the vaccine supply, implementation of a feasible and effective strategy for vaccine delivery, the burden on the public health infrastructure, public acceptability, and financing. Overall, meeting attendees favored incremental expansion of recommendations, potentially toward universal influenza vaccination. They preferred to expand recommendations among children first, because children have a higher risk of illness, compared with healthy adults; because there is greater feasibility of implementation of the recommendations among children; and because of the potential for herd immunity decreasing morbidity and mortality among adults.