National availability of influenza vaccine among medical subspecialty practices

Background: Influenza vaccination rates fall short of national goals, particularly among individuals whose chronic conditions predispose them to complications of influenza. Availability of influenza vaccine in medical subspecialists' practices may affect vaccination rates among adults with chronic illness. Methods: The practice sites of a national random sample of medical cardiology, endocrinology, and pulmonology physicians were contacted by telephone in February 2003 to March 2003 to determine which of them had influenza vaccine available to their patients during the 2002-2003 influenza season. The number of physicians in the practice and geographic location were also obtained. Results: Office staff at the practices of 1683 of 2013 eligible physicians were successfully contacted, and 1473 provided information about vaccine availability. Overall, 1094 (74%) of practices had influenza vaccine available during the 2002-2003 season. Availability differed significantly by subspecialty: 54% cardiology, 78% endocrinology, and 90% pulmonology (p<0.001). Influenza vaccine was more often available at subspecialists' practices in the Northeast (80%) than in the South (74%), Midwest (71%), and West (70%; p<0.005). In multivariate analyses, pulmonology practices in all census regions and sizes were significantly more likely to have influenza vaccine available than was the reference cardiology practice. Several endocrinology practice types also had significantly higher influenza vaccine availability than those in cardiology practice, particularly in multi-physician practices. Conclusions: Influenza vaccine availability varies widely across practices in the three medical subspecialties that provide care to the largest numbers of individuals with an indication for the vaccine in the United States. These findings have implications for the accessibility of influenza vaccine to individuals at high risk for morbidity and mortality associated with influenza.