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DURHAM, N.C. – As America battles the first wave of influenza this season, a new Duke University Medical Center study reveals a major gap in vaccination rates between older African-Americans and whites of the same age. The researchers also found that while vaccination rates in older Americans are on the rise, the elderly as a whole are still under-vaccinated.

To remedy the under-vaccination of such groups, the researchers recommend clinical interventions and public health campaigns that are culturally appropriate and will encourage vaccination against influenza.

"The elderly are at most risk from influenza, and it is a serious public health concern," said Truls Ostbye, M.D., lead author of the study that appears in the online journal BioMed Central Public Health. " Healthy People 2010 -- which identifies our nation's most significant health concerns and designs action plans to address these concerns -- has set the goal that ninety percent of our elderly be vaccinated against influenza annually. Our data show that we have significant work to do to reach this objective." Ostbye is a professor in the department of community and family medicine at Duke.

Most alarming, Ostbye said, is the drastically lower rates of vaccination in the African-American community.

"We see a ten percent to twenty percent point gap in vaccination rates between blacks and whites. Even when we adjust for socioeconomic, health and health care variables, this difference still persists," said Ostbye. "More research is needed to understand the cultural issues that may be a barrier to vaccination in this population."

The Duke researchers examined data from the Health and Retirement Study (HRS) and its companion study, The Asset and Health Dynamics Among the Oldest Old (AHEAD), both of which have been collecting data from 1993 to determine how retirement impacts the health and wealth of American men and women. The studies were funded by the National Institute on Aging. In the HRS study, 12,652 participants aged 50 to 61 in 1992 have been interviewed about their health behaviors, disease and disability, and medical care usage. The AHEAD study, which collected similar data, included 8,124 seniors aged 70 years or older.

In 1995-1996 and in 2000, the HRS and AHEAD studies asked participants if they had received a flu shot within the previous two years. Duke researchers used these two data sets to examine vaccination rates.

The data showed a steady increase in vaccination across all ages, genders and races. The largest increase in vaccination occurred in the 50 to 65 year old bracket, and then plateaued after age 70. In 2000, approximately 75 percent of women over the age of 70 reported that they had received a flu vaccination within the last two years; men were slightly higher at approximately 80 percent.

"The good news here is that more people are getting vaccinated," said Ostbye. "We suspect that a greater acceptance by patients and providers of the vaccine along with increased delivery and administration of the vaccine are at the heart of increase. Economic factors do not seem to play a major role in who gets vaccinated and who does not. For example, racial disparities are larger in our study among persons over age 65, virtually all of whom are covered by Medicare."

When examined by race, the data from 2000 show white women and men close to target with the national average; however, only 60 percent of African-American women and 68 percent of African-American men had received the flu vaccine.

Gary Greenberg, M.D., co-author on the paper and a member of Duke's department of community and family medicine, said that while the Duke study was not designed to isolate reasons for the racial disparities in influenza immunization, general trends in health care may shed light on potential barriers.

"Racial disparities in the receipt of health care services are a common concern in the United States," said Greenberg. "A historical distrust of the health care system may be the basis of some of the problem. Previous studies have shown that in a low-income, urban population, there is a concern about undisclosed vaccine consequences or risks. This fear is a barrier for acceptance of influenza immunization among both blacks and whites."

Greenberg said that the natural reluctance about vaccination might be best combatted with well-promoted personal statements by respected members of the underserved group who endorse and accept vaccination.

The researchers suggest that in order to meet the 90 percent vaccination goal set by Healthy People 2010, culturally appropriate messages about vaccination are needed for underserved communities. Also, additional resources are needed to help coordinate efforts between public health programs and clinical prevention in managed and primary care.

The study was funded by a National Institute on Aging grant, "Perception of Risk and Behavior in the Elderly." Co-authors on the paper include Donald H. Taylor Jr., Ph.D., Duke University Medical Center and Center for Health Policy, Law and Management at the Terry Sanford Institute of Public Policy, Duke University; Lynn Van Scoyoc, Center for Health Policy, Law and Management at the Terry Sanford Institute of Public Policy, Duke University; and Ann Marie M. Lee of Duke University Medical Center.