Where high-risk adults receive influenza vaccine during a shortage.

T he United States has recently experienced influenza vaccine shortages because of manufacturing problems and distribution delays. During the 2004-2005 season, only 61 of the expected 100 million influenza vaccine doses were available to the US market after 1 of the 2 licensed companies withdrew their product. The Centers for Disease Control and Prevention (CDC) recommended that available vaccine be reserved for persons at high risk for influenza-related complications and close contacts of high-risk persons. That year, vaccine coverage levels were lower among those prioritized for influenza vaccination, including older adults, long-term care residents, and health care workers. Only 63% of elderly persons and 46% of adults with chronic conditions who tried were able to obtain the influenza vaccine. Half of adults in high-risk groups did not attempt to get the vaccine, often citing vaccine shortage as an important reason. Ironically, when the influenza season ended, 4 million doses remained undistributed, highlighting the need to improve the supply and demand match. To better understand where consumers obtain influenza vaccine in the setting of limited vaccine supply, we compared influenza vaccine coverage rates and place of vaccination for persons in different risk groups during the 2004-2005 influenza season with the 2003-2004 “nonshortage” baseline.