Examining nursing home segregation and race disparities in influenza vaccinations, this study demonstrates that segregation may increase both susceptibility and exposure to seasonal flu for black Americans. Evidence based on the 2004 U.S. National Nursing Home Survey shows that individuals in nursing homes with high percentages of black residents have less personal immunity to flu because they are less likely to have been vaccinated against the disease; they may also be more likely to be exposed to flu because more of their coresidents are also unvaccinated. This implies that segregation may generate dual disease hazards for contagious conditions. Segregation appears to limit black Americans' access to personal preventive measures against infection, while spatially concentrating those people who are most likely to become contagious.