Important decisions also will need to be made concerning access to vaccination and treatment in the event of a pandemic. The federal government's Draft Guidance on Allocating and Targeting Pandemic Infl uenza Vaccine (38) provides a basic framework for allocating vaccine during the pandemic. An appendix to that document mentions (on p.17) that the principles of "fairness and equity (recognizing that all persons have equal value, and providing equal opportunity for vaccination among all persons in a priority group)" were considered when drafting the guidelines. Although the proposed schema very reasonably fi rst defi nes groups of different priority levels according to occupation and then, within the general population, according to age and pregnancy status, it does not provide explicit attention to groups who are vulnerable because of social disadvantage. Nor does it note the need for explicit attention to vulnerable social subgroups, for example, low-wage workers in prioritized occupational fi elds and low-income and minority pregnant women, infants, and toddlers. We are not questioning the rationality of defi ning major priority groups according to occupation or of using biological criteria to further prioritize within the general population. Rather, our concern is with the absence of attention to both biological and social risk factors, which must be addressed to overcome the many social barriers to equal opportunity for vaccination.