In the fall of 2004, the FDA and British authorities suspended the license of one of only two manufacturers that provided the US supply of inactivated influenza vaccine. With a 50% reduction in supply, a severe vaccine shortage resulted. This situation necessitated the development of priority groups for vaccination including those > or =65 years, when ordinarily, influenza vaccine is recommended for those > or =50 years old. A sample of patients > or =50 years old (n = 336), who had been seen at one of four inner-city health centers, was interviewed in summer 2005 using computer-assisted telephone interviewing. Associations of survey responses were examined for three groups: those vaccinated in the 2003-2004 and 2004-2005 influenza seasons (n = 142), those vaccinated in 2003-2004 but not vaccinated in 2004-2005 because of the shortage (n = 63), and those unvaccinated in both seasons (n = 83). Bivariate and multivariate logistic regression analyses were used to determine factors significantly influencing the likelihood of vaccination status. A significantly larger proportion of patients 50-64 years of age were unvaccinated due to the shortage (73%) compared to those who were vaccinated during both seasons (36%, P or =65 years) and did not result in racial disparities in inner-city health centers.