Parental vaccine safety concerns: results from the National Immunization Survey, 2001-2002.

BACKGROUND: According to the 2002 National Immunization Survey (NIS), vaccination coverage with recommended vaccines among U.S. children aged 19 to 35 months remained near all-time highs. Sustaining this high coverage requires significant effort, including consideration of parental vaccine safety concerns that have led to decreasing coverage in other countries. METHODS: The Parental Knowledge and Experiences module was administered to a random subset of NIS respondents from July 2001 to December 2002. The module included questions regarding attitudes toward vaccine safety and side effects, simultaneous vaccine administration, and acceptance of new vaccines. Multivariate logistic regression analyses examined associations between attitudes and up-to-date (UTD) vaccination coverage (four or more doses of diphtheria and tetanus toxoids and pertussis vaccine, three or more doses of poliovirus vaccine, one or more doses of any measles-containing vaccine, three or more doses of Haemophilus influenzae type b vaccine, and three or more doses of hepatitis B vaccine), while controlling for demographics. RESULTS: Ninety-three percent of parents rated vaccines as safe, 6% as neither safe nor unsafe, and 1% as unsafe. After adjusting for demographics, parental safety belief was significantly associated with the child's vaccination status. For children whose parents believed vaccines are safe, the odds of being UTD were 2.9 times the odds of being UTD for children of parents who believed vaccines are unsafe (75% vs 53%, respectively). Children whose parents were neutral about the safety of vaccines had vaccination coverage similar to children whose parents believed vaccines are unsafe. CONCLUSIONS: A significant association with vaccine coverage was found for a small group of parents with high vaccine safety concerns. Strategies focused on safety concerns may yield better protection for these children.

Factors associated with underimmunization at 3 months of age in four medically underserved areas.

OBJECTIVE: Risk factors for underimmunization at 3 months of age are not well described. This study examines coverage rates and factors associated with under-immunization at 3 months of age in four medically underserved areas. METHODS: During 1997-1998, cross-sectional household surveys using a two-stage cluster sample design were conducted in four federally designated Health Professional Shortage Areas. Respondents were parents or caregivers of children ages 12-35 months: 847 from northern Manhattan, 843 from Detroit, 771 from San Diego, and 1,091 from rural Colorado. A child was considered up-to-date (UTD) with vaccinations at 3 months of age if documentation of receipt of diphtheria-tetanus-pertussis, polio, haemophilus influenzae type B, and hepatitis B vaccines was obtained from a provider or a hand-held vaccination card, or both. RESULTS: Household response rates ranged from 79% to 88% across sites. Vaccination coverage levels at 3 months of age varied across sites: 82.4% in northern Manhattan, 70.5% in Detroit, 82.3% in San Diego, and 75.8% in rural Colorado. Among children who were not UTD, the majority (65.7% to 71.5% per site) had missed vaccines due to missed opportunities. Factors associated with not being UTD varied by site and included having public or no insurance, >/=2 children living in the household, and the adult respondent being unmarried. At all sites, vaccination coverage among WIC enrollees was higher than coverage among children eligible for but not enrolled in WIC, but the association between UTD status and WIC enrollment was statistically significant for only one site and marginally significant for two other sites. CONCLUSIONS: Missed opportunities were a significant barrier to vaccinations, even at this early age. Practice-based strategies to reduce missed opportunities and prenatal WIC enrollment should be focused especially toward those at highest risk of underimmunization.

Counting the shots: a model for immunization screening and referral in nonmedical settings.

BACKGROUND: Clinics of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) have become important partners in efforts to improve vaccination coverage in low income children. However, the time required to assess all antigens in each child's vaccination record may exceed the capacity of many of these clinics. Seeking a solution, experts recommended assessing up-to-date (UTD) status only for the diphtheria-tetanus-acellular-pertussis (DTaP) vaccine and treating this as a proxy measure for all vaccines in the childhood schedule. Whether this single vaccine screening method represents an acceptable alternative to the traditional multiple-vaccine method as a basis for improving overall immunization coverage levels in this vulnerable population has not been demonstrated. OBJECTIVE: To evaluate the validity of the proposed simplified method for assessing immunization status in a nationally representative population of infants and children who had ever been enrolled in WIC before 35 months old. METHODS: This was a cross-sectional analysis of the 2000 National Immunization Survey representing children ages 3 to 24 months who had ever been enrolled in WIC. For the 6277 children in the study population, we compared personal records of completion status for DTaP with personal records of completion status for all immunizations appropriate for age in the combination 4:3:1:3 schedule to see which of the 2 (single vs multiple screening) methods would better predict the child's true (provider-reported) status for the 4:3:1:3 series. The main outcome measures were the comparative sensitivity, specificity, and overall test efficiency of the 2 methods in correctly identifying underimmunized WIC children. RESULTS: Completion status for DTaP was less sensitive than completion status for all vaccinations in correctly identifying truly underimmunized children (sensitivity = 70% and 77%, respectively). However, it was more specific in correctly identifying children who were truly UTD for age (specificity = 86% and 82%, respectively). The 2 methods were essentially identical with respect to overall test efficiency (82% and 81% for DTaP assessment and assessment of all vaccines, respectively). CONCLUSIONS: Given limited resources to do immunization screening and referral in nonmedical settings such as WIC, simplifying the process by using DTaP from the personal vaccination record as a proxy for the 4:3:1:3 series is a viable option. Loss in sensitivity may well be offset by gains in the capacity of WIC clinics to screen more children.

Emerging issues in vaccine economics: perspectives from the USA.

Economic studies of vaccines, including vaccine development and delivery issues, are increasingly needed to inform policy recommendations and programmatic decisions in the USA. This need arises from the increasing costs of vaccines, the complexity of the US healthcare system and the limited number of vaccine manufacturers in the market. We have developed a national research agenda in domestic and global vaccine economics by conducting key informant interviews with 42 experts and inviting ideas from an additional 128 experts. To assess priorities among the 129 ideas that were generated, we asked 15 experts representing a broad range of perspectives to rank the ideas and we analyzed their votes. The highest-ranking domestic research ideas included evaluating: the costs of vaccine shortages, the cost-effectiveness of potential human papillomavirus vaccination and adult and adolescent pertussis vaccination programs and the cost-effectiveness of universal vaccine purchase programs for adults as well as children. The highest-ranking globally-oriented ideas included developing a resource allocation model to support the best vaccination program decisions with limited funds and assessing the cost-effectiveness of HIV, rotavirus, meningococcal and malaria vaccines in developing countries. To optimize the usefulness of vaccine economics research, conceptual issues, such as how to set values for the prevention of illness and how to maximize social equity through investments in vaccines, must be addressed.