Vincent Mor, a Brown professor of health services policy and practice, and Shubing Cai, a Brown community health investigator, analyzed thousands of patient records from more than 14,000 nursing homes between 2006 and 2008. The two published their findings in Health Affairs, along with coauthors and fellow Brown faculty members Zhanlian Feng, an assistant professor of health services, policy, and practice, and Mary Fennell, professor of sociology and community health.

Mor and Cai concluded that the discrepancy was even greater when blacks and whites lived in different nursing homes. Blacks were then 23 percent less likely than whites to get shots.

Cai says some of the difference could be attributed to ignorance rather than prejudice. African Americans turn down flu shots at higher rates than other groups—13 percent, in contrast to a 9 percent refusal rate among whites.

"The way to address the within-facility disparity," Mor says, "is to find out why there are these refusals and determine better ways of communicating the vaccine's benefits."