摘要：Objective. We examined heptavalent pneumococcal conjugate vaccine (PCV7) uptake among children aged 19 to 35 months in the United States and determined how uptake rates differed by state vaccine financing policy. Methods. We analyzed data from the 2001–2003 National Immunization Survey. States that changed their vaccine financing policy between 2001 and 2003 (n=17) were excluded from analysis. Logistic regression was performed to identify the association between state vaccine financing policy and receipt of 3 or more doses of PCV7 after control for demographic characteristics. Results. The proportion of children receiving 3 or more doses increased from 6.7% in 2001 to 69.0% in 2003. After controlling for demographic characteristics, children residing in states that provided all vaccines except PCV7 to all children had lower odds of receiving 3 or more doses compared to children residing in states that provided PCV7 only to children eligible for the Vaccines for Children program (odds ratio=0.58; 95% confidence interval=0.51, 0.66). Conclusion. It is essential that we continue to monitor the effect that state vaccine financing policy has on the delivery of PCV7 and future vaccines, which are likely to be increasingly expensive. In February 2000, heptavalent pneumococcal conjugate vaccine (PCV7) was licensed for routine vaccination of young children. Soon after licensure, the Advisory Committee on Immunization Practices (ACIP) recommended the vaccine for all children aged 2 to 23 months and for those children aged 24 to 59 months who are at increased risk of pneumococcal disease, specifically American Indian/Alaska Native and Black children. 1 The ACIP recommends administering doses at 2, 4, 6, and 12–15 months of age. 1 The number of doses needed depends on the age at first dose. The vaccine has been shown to effectively reduce invasive pneumococcal infections in children and adults 2 – 5 and to reduce the incidence of otitis media. 2 Studies conducted soon after vaccine licensure showed that more than 80% of physicians had adopted the ACIP recommendations for PCV7. 6 , 7 As with other new vaccines, 8 the vaccine was not incorporated into routine practice policy uniformly across physician types; more than 90% of pediatricians were offering the vaccine to their patients compared to only 55% to 68% of family physicians. 6 , 7 Although the majority of physicians were offering the vaccine to their patients, 2 obstacles stood in the way of a seamless transition from vaccine licensure to vaccine administration: the cost of the vaccine and difficulties sustaining an adequate supply to meet consumer demand. PCV7 is currently the second most expensive vaccine included in the routine childhood vaccination schedule; as of March 2006, 1 dose of PCV7 cost $54.12 if purchased via federal contracts or $65.95 if purchased privately. 9 By contrast, the cost of other vaccines included in the routine childhood vaccination schedule purchased through federal contracts ranges from $7.66 per dose ( Haemophilus influenzae type b) to $74.85 per dose (measles, mumps, rubella, and varicella). 9 Initially, there was a delay in insurance carriers’ adding PCV7 to their benefit packages, and some insured patients had to pay out-of-pocket costs for the vaccine. Consequently, many physicians reported referring patients without adequate coverage for PCV7 to health departments. 10 Moreover, states’ vaccine financing policies differ, which may make it difficult for some children to receive PCV7. All states receive funds to purchase vaccines for children eligible for the Vaccines for Children (VFC) program, which was developed to eliminate cost as a barrier to receiving vaccines. To be eligible for VFC, children must be enrolled in Medicaid, uninsured, of American Indian/Alaska Native descent, or underinsured but receiving vaccines at a federally qualified health center. States have the option of using other federal and state funds to purchase additional vaccines for children not eligible for VFC as a way to enhance their VFC program. However, some states that have chosen to enhance their VFC program have excluded PCV7 from their policy because of the cost of the vaccine. Since PCV7 was licensed for use, the United States has experienced 2 severe shortages of the vaccine. 11 , 12 The first shortage occurred between August 2001 and May 2003 and the second between November 2003 and September 2004. During both shortages, the ACIP released interim recommendations to providers to suspend the administration of the third and fourth doses of the series. 13 – 15 The shortages occurred in all states independent of region 16 , 17 and, thus, independent of state vaccine financing policy. The timing and duration of these shortages, particularly the first, have obvious implications for vaccine uptake. We examined uptake of PCV7 among children aged 19 to 35 months residing in the United States and analyzed how uptake rates differed by state vaccine financing policy. Our primary hypothesis was that children residing in states that excluded PCV7 from their financing policy would be less likely to receive 3 or more doses of the vaccine compared with children living in states with a policy that included PCV7.
