Abstract
Annual influenza vaccination of the US elderly population has been demonstrated as safe and effective in reducing the risks of illness, hospitalization, and death. The Medicare Current Beneficiary Survey (MCBS) has measured annual influenza vaccination rates since 1991; the latest data available are for the 2001–2002 influenza season. Since 1996, self-reported reasons for not receiving influenza vaccine also have been measured. During 1991–2002, MCBS indicated a steady upward trend in vaccination coverage among Medicare beneficiaries, with the exception of the 2000–2001 influenza season, when vaccine distribution was delayed. The most frequently cited reasons for not receiving influenza vaccine were not knowing that influenza vaccination was needed and concerns that vaccination might cause influenza or adverse effects. During the 2000–2001 influenza season, vaccine shortage or unavailability was noted for the first time as an important reason for nonvaccination.
During the 2000–2001 influenza season, the vaccination rate declined instead of maintaining an annual increase; 67.0% (20.5 million Medicare beneficiaries aged ≥65 years living in the community) reported receiving the vaccine compared with a record high of 70.0% (21.2 million) in 1999–2000. For the 2001–2002 influenza season, 68.8% (21.3 million) reported receiving influenza vaccine.
Consequences from the vaccine shortage in 2000–2001 were limited because of the mildness of the influenza virus that season. The CDC has previously estimated that, for each 1 million elderly persons vaccinated, approximately 900 deaths and 1300 hospitalizations are prevented. Influenza vaccination rates are used as indicators of progress toward achieving the national health objectives for 2010. A long-term, structured campaign to promote the benefits of vaccination to Medicare beneficiaries and improve provider performance has resulted in large increases in vaccination during the preceding decade. However, even the strongest efforts of government agencies to promote vaccination are subject to the constraints of limited vaccine supply. During the current influenza vaccine shortage, vaccine is prioritized for populations at high risk, including the elderly.