Evaluation of Group Health Cooperative of Puget Sound's Senior Influenza Immunization Program.

The goal of this study was to identify areas in which an influenza immunization campaign for seniors, sponsored by a health maintenance organization (HMO), could be improved. This study was conducted at Group Health Cooperative of Puget Sound (GHC), serving approximately 470,000 enrollees in Washington State. A survey was administered to two groups of seniors drawn at random--those who received influenza vaccine and those who did not, during the fall and winter of 1991. Immunization rates were almost 75 percent for "well" seniors and 85 percent for "chronically ill" seniors. Bivariant analysis showed that two activities of the influenza campaign were associated with vaccine compliance: a provider-generated recruitment letter and exposure to an immunization article in the enrollee newsletter. Using a broader framework for predicting vaccine compliance, logistic regression showed that vaccine compliance was associated positively with previous immunizations and belief that "my doctor wants me to get a shot," and negatively with fear of adverse reaction and belief that the vaccine is ineffective. There were few suggestions for improving the immunization program, among both vaccinated and unvaccinated enrollees. Approximately two-thirds of unvaccinated enrollees said there was nothing GHC could do to convince them to be vaccinated. These findings suggest high vaccine compliance and satisfaction with an HMO-sponsored influenza campaign. Strategies and potential to further increase vaccination rates are discussed.