Among persons who have been exposed to infl uenza virus, the likelihood of contracting disease may be modifi ed by underlying host factors and medical conditions, such as age, smoking status, nutritional status, stress levels, and cardiopulmonary disease. The infl uence that most host factors will have on the development of infl uenza during a future pandemic is uncertain; some evidence suggests that the factors affecting disease severity and death may differ from those typically observed during annual infl uenza epidemics (19) . However, given overwhelming evidence that low-income persons are generally more susceptible to infectious diseases, it is reasonable to plan on the basis of well-documented annual epidemic patterns, in which infl uenza disease development is infl uenced by factors that are differentially distributed across socioeconomic and racial/ ethnic groups. These patterns, as well as patterns of many other diseases, indicate that socially disadvantaged groups are likely to be at higher risk for infl uenza disease, particularly severe disease. The inability to predict which infl uenza virus will cause a future pandemic, together with the very limited national and global capacity to produce infl uenza vaccine in massive quantities in a short time, almost ensures that an effective vaccine will be unavailable to most or all of the population during the early stages of a pandemic and in very short supply thereafter. Even so, current plans assume that local and state public health agencies will have a primary role for distributing pandemic infl uenza vaccine. In general, however, these plans do not adequately address preventing or minimizing socioeconomic or racial/ethnic disparities in vaccine distribution and acceptance, despite evidence that such disparities have been the rule for the annual infl uenza vaccine, even among persons >65 years of age (20) . In the United States, routine use of annual infl uenza vaccine in preschool children has only recently been introduced; information focusing on school-age children is limited (21) . Nevertheless, African American/black children and children from lower income families, who are at higher risk of contracting infl uenza (22) in this country, are less likely to be up to date with other routine immunizations (23) . It is possible that, in the context of an infl uenza pandemic, vaccine-seeking and acceptance behavior and resultant coverage patterns may differ from those observed during routine vaccination efforts; however, the weight of available evidence indicates that social disparities in vac-cine coverage are likely to occur in the absence of careful planning to prevent them.