beliefs about and understanding of the relative risks and benefits of immunization for these diseases. Coverage of persons aged 65 and older for influenza vaccine climbed steadily during the past decade, from 42 percent in 1991 to 63 percent in 1997 (see Table 3–6). The cumulative (ever vaccinated) coverage levels for pneumococcal vaccine for the elderly between 1991 and 1997 doubled from 21 to 42 percent (see Table 3–6). Yet racial and ethnic disparities in immunization rates for the elderly have persisted. In 1997, the influenza immunization rate for elderly blacks was just two-thirds that for whites (45 as compared with 66 percent), and the pneumococcal immunization rate for both blacks and Hispanics was half that for whites (22–23 percent as compared with 46 percent). For noninstitutionalized high-risk adults aged 18–64 (often those with chronic illness such as heart and lung disease or diabetes), coverage rates in 1997 for influenza vaccine were 47 percent for those with Medicare (disabled or ESRD beneficiaries), 29 percent for those with private insurance, and 14 percent for those without insurance. Pneumococcal vaccine coverage rates for high-risk adults aged 18–64 were 28 percent for those with Medicare, 12 percent for those with private insurance, and 10 percent for those without insurance (see Table 3–6).
The number of adults aged 18–65 who are at high risk of complications from influenza and pneumococcal disease, for whom immunization is strongly recommended, is roughly 26 million (11 percent of those aged 18–44 and 24 percent of those aged 45–64 have chronic conditions that put them at risk) (Singleton et al., forthcoming). Of these, about one-fifth, or 5 million high-risk nonelderly adults, lack health insurance, and thus have no coverage for these immunizations. As noted earlier, there is very little information on the extent to which private health plans cover adult immunizations. Although the extent of the high-risk population facing financial barriers to receiving immunizations cannot be estimated precisely, the number is likely to be substantially greater than the 5 million who are completely uninsured (see Box 3–3).
As with Medicaid managed care, Medicare beneficiaries enrolled in Medicare+Choice plans may qualify for additional benefits, including all routine or recommended immunizations. As of February 2000, 6.8 million Medicare beneficiaries were enrolled in prepaid managed care plans— almost five times as many as were enrolled in 1991 (information provided by HCFA).24 With increasing numbers of Medicare beneficiaries enrolled in managed care, the program costs for immunizations cannot be determined separately, nor can immunization coverage levels be estimated from billing records, as such records are not available for prepaid plan enrollees. Adult influenza coverage levels are currently a Health Plan Employer Data and Information Set (HEDIS)-reported measure, however, and pneumococcal coverage levels may be added in the near future (Poland