An important standard for childhood immunization is simultaneous administration of all age-eligible doses of vaccines. Vaccination coverage for ≥4 doses of pneumococcal conjugate vaccine (PCV) for children 19-35 months has not achieved the Healthy People 2020 objective of 90% in the United States, and the fourth dose of PCV is commonly missed in the series. Research has not been conducted on the factors associated with missed opportunities for simultaneous administration of the fourth dose of PCV. A missed opportunity for simultaneous administration of the fourth dose of PCV is characterized as failing to administer an age-appropriate fourth dose of PCV to children when in the same provider visit the children did receive other age-eligible vaccines. During the period of 2008-2015, 4.5% to 7.8% of young children in the United States experienced missed opportunities for simultaneous administration of the fourth dose of PCV; across all selected factors, the proportion of missed opportunities varied from 4.1% to 11.3%. The timeliness of the first through the third doses of PCV vaccination, and age group of mothers were factors significantly related to missed opportunities for simultaneous administration of the fourth dose of PCV; the adjusted prevalence ratios ranged from 1.2 to 2.0. Missed opportunities could be reduced by provider implementation of systems to ensure that all recommended vaccines are offered at each visit. Systems tools providers could use to reduce missed opportunities include patient recall, provider reminders, standing orders, extended office hours, and use of immunization information systems (IIS).

Declining response rates may introduce bias into survey results and increase costs. Two national surveys, the National Immunization Survey (NIS) and the NIS-Teen, were used to study the impact of survey length, as stated by the interviewer, and inclusion of a topic of interest to respondents on response rates. The two studies included comparisons of the standard survey instruments to revised, condensed instruments. The NIS study also included variations of the standard survey with sections considered of interest for parental respondents, the Parental Concerns Module (PCM), which contained questions about parents' thoughts and beliefs about vaccinations. The outcomes of interest were differences in the response rates and resulting survey costs in each of the study conditions. The shortened instruments resulted in higher response rates compared to both the standard instruments and the instruments including the PCM and reduced the overall time needed to complete an interview. Based on these results, the NIS and NIS-Teen questionnaires were both shortened.

BACKGROUND: Vaccination requirements for kindergarten entry vary by state, but all states require 2 doses of measles containing vaccine (MCV) at kindergarten entry. OBJECTIVE: To assess (i) national MCV vaccination coverage for children who had attended kindergarten; (ii) the extent to which undervaccination after kindergarten entry is attributable to parents' requests for an exemption; (iii) the extent to which undervaccinated children had missed opportunities to be administered missing vaccine doses among children whose parent did not request an exemption; and (iv) the vaccination coverage gap between the "highest achievable" MCV coverage and actual MCV coverage among children who had attended kindergarten. METHODS: A national survey of 1465 parents of 5-7year-old children was conducted during October 2013 through March 2014. Vaccination coverage estimates are based provider-reported vaccination histories. Children have a "missed opportunity" for MCV if they were not up-to-date and if there were dates on which other vaccines were administered but not MCV. The "highest achievable" MCV vaccination coverage rate is 100% minus the sum of the percentages of (i) undervaccinated children with parents who requested an exemption; and (ii) undervaccinated children with parents who did not request an exemption and whose vaccination statuses were assessed during a kindergarten grace period or period when they were provisionally enrolled in kindergarten. RESULTS: Among all children undervaccinated for MCV, 2.7% were attributable to having a parent who requested an exemption. Among children who were undervaccinated for MCV and whose parent did not request an exemption, 41.6% had a missed opportunity for MCV. The highest achievable MCV coverage was 98.6%, actual MCV coverage was 90.9%, and the kindergarten vaccination gap was 7.7%. CONCLUSION: Vaccination coverage may be increased by schools fully implementing state kindergarten vaccination laws, and by providers assessing children's vaccination status at every clinic visit, and administering missed vaccine doses.

BACKGROUND: Simultaneous administration of all age-appropriate doses of vaccines is an effective strategy for raising vaccination coverage. Vaccination coverage for ≥4 dose of DTaP (diphtheria, tetanus toxoids, and acellular pertussis vaccine) among children 19-35months in the United States has not reached the Healthy People 2020 target of 90%. Risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP have not been investigated. METHODS: A missed opportunity for simultaneous administration of the fourth dose of DTaP is defined as the failure to administer an age-eligible fourth dose of DTaP, and during the same age-eligible period for the fourth dose of DTaP other recommended and age-appropriate doses of vaccines are given to children. This study used 2001-2014 National Immunization Survey data to describe the trend in missed opportunities for simultaneous administration of the fourth dose of DTaP from 2001 through 2014, assess the prevalence of children who missed opportunities for simultaneous administration of the fourth dose of DTaP by selected factors, and recognize significant risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP. RESULTS: From 2001 to 2014, the prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP among children 19-35months in the United States ranged from 5.7% to 9.0%; across 13 factors considered, the prevalence of missed opportunities varied from 3.3% to 22.9%. Children who were late in receiving the first to third dose of DTaP had significantly higher prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP than children who received these doses on-time, with adjusted prevalence ratios for late vs. on-time of 1.7, 1.6, and 3.2, and all P-value<0.01. CONCLUSIONS: Improving on-time vaccination of the third dose of DTaP could substantially reduce missed opportunities for simultaneous administration of the fourth dose of DTaP.

BACKGROUND: Routine administration of all age-appropriate doses of vaccines during the same visit is recommended for children by the National Vaccine Advisory Committee (NVAC) and the Advisory Committee on Immunization Practices (ACIP). METHODS: Evaluate the potentially achievable vaccination coverage for ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine (4+DTaP), ≥4 doses of pneumococcal conjugate vaccine (4+PCV), and the full series of Haemophilus influenzae type b vaccine (Hib-FS) with simultaneous administration of all recommended childhood vaccines. Compare the potentially achievable vaccination coverage to the reported vaccination coverage for calendar years 2001 through 2013; by state in the United States and by selected socio-demographic factors in 2013. The potentially achievable vaccination coverage was defined as the coverage possible for the recommended 4+DTaP, 4+PCV, and Hib-FS if missed opportunities for simultaneous administration of all age-appropriate doses of vaccines for children had been eliminated. RESULTS: Compared to the reported vaccination coverage, the potentially achievable vaccination coverage for 4+DTaP, 4+PCV, and Hib-FS could have increased significantly (P<0.001), the vaccination coverage would have achieved the 90% target of Healthy People 2020 for the three vaccines beginning in 2005, 2008, and 2011 respectively. In 2013, the potentially achievable vaccination coverage increased significantly across all selected socio-demographic factors, potentially achievable vaccination coverage would have reached the 90% target for more than 51% of the states in the United States. CONCLUSIONS: The findings in this study suggest that fully utilization of all opportunities for simultaneous administration of all age-eligible childhood doses of vaccines during the same vaccination visit is a critical strategy for increasing vaccination coverage and improving timely vaccination for children. Encouraging providers to deliver all recommended vaccines that are due at each visit by implementing client reminder and recall systems might decrease missed opportunities for simultaneous administration of childhood vaccines.

BACKGROUND: Between 2010 and 2014, the percentage of 13-17 year-old girls administered ≥3 doses of the human papilloma virus (HPV) vaccine ("fully vaccinated") increased by 7.7 percentage points to 39.7%, and the percentage not administered any doses of the HPV vaccine ("not immunized") decreased by 11.3 percentage points to 40.0%. OBJECTIVE: To evaluate the complex interactions between parents' vaccine-related beliefs, demographic factors, and HPV immunization status. METHODS: Vaccine-related parental beliefs and sociodemographic data collected by the 2010 National Immunization Survey-Teen among teen girls (n=8490) were analyzed. HPV vaccination status was determined from teens' health care provider (HCP) records. RESULTS: Among teen girls either unvaccinated or fully vaccinated against HPV, teen girls whose parent was positively influenced to vaccinate against HPV were 48.2 percentage points more likely to be fully vaccinated. Parents who reported being positively influenced to vaccinate against HPV were 28.9 percentage points more likely to report that their daughter's HCP talked about the HPV vaccine, 27.2% percentage points more likely to report that their daughter's HCP gave enough time to discuss the HPV shot, and 43.4 percentage points more likely to report that their daughter's HCP recommended the HPV shot (p<0.05). Among teen girls administered 1-2 doses of the HPV vaccine, 87.0% had missed opportunities for HPV vaccine administration. CONCLUSION: Results suggest that an important pathway to achieving higher ≥3 dose HPV vaccine coverage is by increasing HPV vaccination series initiation though HCP talking to parents about the HPV vaccine, giving parents time to discuss the vaccine, and by making a strong recommendation for the HPV. Also, HPV vaccination series completion rates may be increased by eliminating missed opportunities to vaccinate against HPV and scheduling additional follow-up visits to administer missing HPV vaccine doses.

BACKGROUND: Vaccination programmes to prevent outbreaks after introductions of infectious people aim to maintain the average number of secondary infections per infectious person at one or less. We aimed to assess heterogeneity in vaccine uptake and other characteristics that, together with non-random mixing, could increase this number and to evaluate strategies that could mitigate their impact. METHODS: Because most US children attend elementary school in their own neighbourhoods, surveys of children entering elementary school (age 5 years before Sept 1) allow assessment of spatial heterogeneity in the proportion of children immune to vaccine-preventable diseases. We used data from a 2008 school-entry survey by the Immunization Division of the California Department of Public Health to obtain school addresses; numbers of students enrolled; proportions of enrolled students who had received one or two doses of the measles, mumps, and rubella (MMR) vaccine; and proportions with medical or personal-belief exemptions. Using a mixing model suitable for spatially-stratified populations, we projected the expected numbers of secondary infections per infectious person for measles, mumps, and rubella. We also mapped contributions to this number for measles in San Diego County's 638 elementary schools and its largest district, comprising 200 schools (31%). We then modelled the effect on measles' realised reproduction number (RV) of the following plausible interventions: vaccinating all children with personal-belief exemptions, increasing uptake by 10% to 50% in all low-immunity schools (<90% of students immune) or in only influential (effective daily contact rates >3 or contacts inter-school >30%) low-immunity schools, and increasing private school uptake to the public school average. FINDINGS: In 2008, 39 132 children began elementary school in San Diego County, CA, USA. At entry to school, 97% had received at least one dose of the MMR vaccine, with 2.5% having personal-belief exemptions. We note substantial heterogeneity in immunity throughout the county. Although the average population immunities for measles, mumps, and rubella (92%, 87%, 92%) were similar to the population-immunity thresholds in homogeneous, randomly-mixing populations (91%, 88%, 76%), after accounting for heterogeneity and non-random mixing, the basic reproduction numbers increased by 70%, meaning that introduced pathogens could cause outbreaks. The impact of our modelled interventions ranged from negligible to a nearly complete reduction in the outbreak potential of measles. The most effective intervention to lower the realised reproduction number (RV 3.39) was raising immunity by 50% in 114 schools with low immunity (RV 1.02), but raising immunity by this level in only influential, low-immunity schools also was effective (RV 2.02). The effectiveness of vaccinating the 972 children with personal-belief exemptions was similar to that of targeting all low-immunity schools (RV 1.11). Targeting only private schools had little effect. INTERPRETATION: Our findings suggest that increasing vaccine uptake could prevent outbreaks such as that of measles in San Diego in 2008. Vaccinating children with personal-belief exemptions was one of the most effective interventions that we modelled, but further research on mixing in heterogeneous populations is needed.

Careful design of a dual-frame random digit dial (RDD) telephone survey requires selecting from among many options that have varying impacts on cost, precision, and coverage in order to obtain the best possible implementation of the study goals. One such consideration is whether to screen cell-phone households in order to interview cell-phone only (CPO) households and exclude dual-user household, or to take all interviews obtained via the cell-phone sample. We present a framework in which to consider the tradeoffs between these two options and a method to select the optimal design. We derive and discuss the optimum allocation of sample size between the two sampling frames and explore the choice of optimum p, the mixing parameter for the dualuser domain. We illustrate our methods using the National Immunization Survey, sponsored by the Centers for Disease Control and Prevention.

Routine human papillomavirus (HPV) vaccination is recommended at 11 or 12 years by the Advisory Committee on Immunization Practices. National Immunization Survey-Teen data were analyzed to evaluate, among girls, coverage with one or more doses of HPV vaccination, missed opportunities for HPV vaccination, and potential achievable coverage before 13 years. Results were stratified by birth year cohorts. HPV vaccination coverage before 13 years (≥1 HPV dose) increased from 28.4% for girls born in 1995 to 46.8% for girls born in 2000. Among girls born during 1999-2000 who had not received HPV vaccination before 13 years (57.2%), 80.1% had at least 1 missed opportunity to receive HPV vaccination before 13 years. Opportunities to vaccinate for HPV at age 11 to 12 years are missed. Strategies are needed to decrease these missed opportunities for HPV vaccination. This can be facilitated by the administration of all vaccines recommended for adolescents at the same visit.

BACKGROUND: In 2011, the Advisory Committee for Immunization Practices (ACIP) recommended routine use human papillomavirus (HPV) vaccine for male adolescents. METHODS: We used the 2013 National Immunization Survey-Teen data to assess HPV vaccine uptake (≥1 dose) and series completion (≥3 doses). Multivariable logistic regression analysis and a predictive marginal model were conducted to identify independent predictors of vaccination among adolescent males aged 13 to 17 years. RESULTS: HPV vaccination coverage with ≥1 dose was 34.6%, and series completion (≥3 doses) was 13.9%. Coverage was significantly higher among non-Hispanic blacks and Hispanics compared with non-Hispanic white male adolescents. Multivariable logistic regression showed that characteristics independently associated with a higher likelihood of HPV vaccination (≥1 dose) included being non-Hispanic black race or Hispanic ethnicity; having mothers who were widowed, divorced, or separated; having 1 to 3 physician contacts in the past 12 months; a well-child visit at age 11 to 12 years; having 1 or 2 vaccination providers; living in urban or suburban areas; and receiving vaccinations from >1 type of facility (P < .05). Having mothers with some college or college education, having a higher family income to poverty ratio, living in the South or Midwest, and receiving vaccinations from all sexually transmitted diseases/school/teen clinics or other facilities were independently associated with a lower likelihood of HPV vaccination (P < .05). CONCLUSIONS: Following recommendations for routine HPV vaccination among male adolescents, uptake in 2013 was low in this population. Increased efforts are needed to improve vaccination coverage, especially for those who are least likely to be vaccinated.

The goal of many vaccination programs is to attain the population immunity above which pathogens introduced by infectious people (e.g., travelers from endemic areas) will not cause outbreaks. Using a simple meta-population model, we demonstrate that, if sub-populations either differ in characteristics affecting their basic reproduction numbers or if their members mix preferentially, weighted average sub-population immunities cannot be compared with the proportionally-mixing homogeneous population-immunity threshold, as public health practitioners are wont to do. Then we review the effect of heterogeneity in average per capita contact rates on the basic meta-population reproduction number. To the extent that population density affects contacts, for example, rates might differ in urban and rural sub-populations. Other differences among sub-populations in characteristics affecting their basic reproduction numbers would contribute similarly. In agreement with more recent results, we show that heterogeneous preferential mixing among sub-populations increases the basic meta-population reproduction number more than homogeneous preferential mixing does. Next we refine earlier results on the effects of heterogeneity in sub-population immunities and preferential mixing on the effective meta-population reproduction number. Finally, we propose the vector of partial derivatives of the reproduction number with respect to the sub-population immunities as a fundamentally new tool for targeting vaccination efforts.

OBJECTIVE: We evaluated the extent to which children and adolescents were not vaccinated against measles ("unvaccinated"), clustering within U.S. counties, and factors associated with unvaccination, including parents' vaccine-related beliefs and missed opportunities. METHODS: We analyzed data from the 2010-2013 National Immunization Survey (NIS) and NIS-Teen Survey of households with 19- to 35-month-old children and 13- to 17-year-old adolescents, respectively. We used provider-reported vaccination histories to assess measles vaccination status. RESULTS: In 2013, 7.5% of children and 4.5% of adolescents were unvaccinated against measles. Four-fifths (80.0%) of unvaccinated children lived in counties containing 41.9% of the nation's children, and 80.0% of unvaccinated adolescents lived in counties containing 30.4% of the nation's adolescents. Multivariable statistical analyses found that 74.6% of children who were unvaccinated against measles missed being vaccinated for reasons other than parents' negative vaccine-related beliefs, and 89.6% could be deemed as having at least one missed opportunity for being vaccinated against measles because they were administered at least one dose of other recommended vaccines after 12 months of age. Among adolescents, multivariable analyses found that only demographic factors, not vaccine-related parental beliefs, were independently associated with being unvaccinated. CONCLUSIONS: Reasons other than negative vaccine-related beliefs, including missed opportunities, accounted for the vast majority of unvaccinated children and adolescents.

BACKGROUND: The Vaccines for Children (VFC) program provides vaccines at no cost to children who are Medicaid-eligible, uninsured, American Indian or Alaska Native (AI/AN), or underinsured and vaccinated at Federally Qualified Health Centers or Rural Health Clinics. The objective of this study was to compare influenza vaccination coverage of VFC-entitled to privately insured children in the United States, nationally, by state, and by selected socio-demographic variables. METHODS: Data from the National Immunization Survey-Flu (NIS-Flu) surveys were analyzed for the 2011-2012 and 2012-2013 influenza seasons for households with children 6 months-17 years. VFC-entitlement and private insurance status were defined based upon questions asked of the parent during the telephone interview. Influenza vaccination coverage estimates of children VFC-entitled versus privately insured were compared by t-tests, both nationally and within state, and within selected socio-demographic variables. RESULTS: For both seasons studied, influenza coverage for VFC-entitled children did not significantly differ from coverage for privately insured children (2011-2012: 52.0%+/-1.9% versus 50.7%+/-1.2%; 2012-2013: 56.0%+/-1.6% versus 57.2%+/-1.2%). Among VFC-entitled children, uninsured children had lower coverage (2011-2012: 38.9%+/-4.7%; 2012-2013: 44.8%+/-3.5%) than Medicaid-eligible (2011-2012: 55.2%+/-2.1%; 2012-2013: 58.6%+/-1.9%) and AI/AN children (2011-2012: 54.4%+/-11.3%; 2012-2013: 54.6%+/-7.0%). Significant differences in vaccination coverage among VFC-entitled and privately insured children were observed within some subgroups of race/ethnicity, income, age, region, and living in a metropolitan statistical area principle city. CONCLUSIONS: Although finding few differences in influenza vaccination coverage among VFC-entitled versus privately insured children was encouraging, nearly half of all children were not vaccinated for influenza and coverage was particularly low among uninsured children. Additional public health interventions are needed to ensure that more children are vaccinated such as a strong recommendation from health care providers, utilization of immunization information systems, provider reminders, standing orders, and community-based interventions such as educational activities and expanded access to vaccination services.

The Presidential Childhood Immunization Initiative was developed in 1993 to address major gaps in childhood vaccination coverage in the United States. Eliminating the cost of vaccines as a barrier to vaccination was one strategy of the Childhood Immunization Initiative; it led to Congressional legislation that authorized creation of the Vaccines for Children program (VFC) in 1994. CDC analyzed National Immunization Survey data for 1995-2011 to evaluate trends in disparities in vaccination coverage rates between non-Hispanic white children and children of other racial/ethnic groups. VFC has been effective in ireducing disparities in vaccination coverage among U.S. children. CDC's Office of Minority Health and Health Equity selected the intervention analysis and discussion that follows to provide an example of a program that has been effective in reducing childhood vaccination coverage-related disparities in the United States. At its inception in 1994, VFC was implemented in 78 Immunization Action Plan areas that covered the entire United States; within each area, concerted efforts were made to improve childhood vaccination coverage. The findings in this report demonstrate that there have been no racial/ethnic disparities in vaccine coverage for measles-mumps-rubella and poliovirus in the United States since 2005. Disparities in coverage for the diphtheria-tetanus-pertussis/diphtheria-tetanus-acellular pertussis vaccine were absent, declining, or inconsistent during this period, depending on the racial/ethnic group examined. The results in this report highlight the effectiveness of VFC.

Human papillomavirus (HPV) vaccine coverage among girls is low. We used data reported by parents of 4103 girls, 13 to 17 years old, to assess associations with, and reasons for, delaying or refusing HPV vaccination. Sixty-nine percent of parents neither delayed nor refused vaccination, 11% delayed only, 17% refused only, and 3% both delayed and refused. Eighty-three percent of girls who delayed only, 19% who refused only, and 46% who both delayed and refused went on to initiate the vaccine series or intended to initiate it within the next 12 months. A significantly higher proportion of parents of girls who were non-Hispanic white, lived in households with higher incomes, and had mothers with higher education levels, delayed and/or refused vaccination. The most common reasons for nonvaccination were concerns about lasting health problems from the vaccine, wondering about the vaccine's effectiveness, and believing the vaccine is not needed.

BACKGROUND: Healthcare provider (HCP) reporting to the vaccine adverse event reporting system (VAERS) is important to assuring the safety of U.S. licensed vaccines. HCP awareness of and practices regarding reporting of adverse events following immunization (AEFI) is understudied. METHODS: A large, nationally representative sample of U.S. office-based HCP across three occupational groups (physicians, mid-level providers [physician assistants, advanced practice nurses] and nurses) and three primary care practice areas (pediatrics, family medicine, internal medicine) were surveyed utilizing standardized methodology. We assessed HCP familiarity with VAERS, the situations under which they were likely to report an AEFI, and the methods they used and preferred for reporting. We used logistic regression to determine factors associated with HCP not reporting AEFI to VAERS. RESULTS: Our survey response rate was 54.9%. The percentage of HCP aware of VAERS (71%) varied by occupation and primary care practice area. About 40% of HCP had identified at least one AEFI with only 18% of these indicating that they had ever reported to VAERS. More serious events were more likely to be reported. Factors associated with HCP not reporting AEFI included: HCP not familiar versus very familiar with filing a paper VAERS report (OR=12.84; p<0.0001), primary care practice area of internal medicine versus pediatrics (OR=4.22; p=0.0005), and HCP not familiar versus very familiar with when it was required to file a VAERS report (OR=5.52; p=0.0013). CONCLUSIONS: Specific educational interventions targeted to HCP likely to see AEFI but not currently reporting may improve vaccine safety reporting practices.

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OBJECTIVES: The United States eliminated indigenous wild polioviruses (WPVs) in 1979 and switched to inactivated poliovirus vaccine in 2000, which quickly ended all indigenous live poliovirus transmission. Continued WPV circulation and use of oral poliovirus vaccine globally allow for the possibility of reintroduction of these viruses. We evaluated the risk of a U.S. polio outbreak and explored potential vaccine needs for outbreak response. METHODS: We synthesized information available on vaccine coverage, exemptor populations, and population immunity. We used an infection transmission model to explore the potential dynamics of a U.S. polio outbreak and potential vaccine needs for outbreak response, and assessed the impacts of heterogeneity in population immunity for two different subpopulations with potentially low coverage. RESULTS: Although the risk of poliovirus introduction remains real, widespread transmission of polioviruses appears unlikely in the U.S., given high routine coverage. However, clusters of un- or underimmunized children might create pockets of susceptibility that could potentially lead to one or more paralytic polio cases. We found that the shift toward combination vaccine utilization, with limited age indications for use, and other current trends (e.g., decreasing proportion of the population with immunity induced by live polioviruses and aging of vaccine exemptor populations) might increase the vulnerability to poliovirus reintroduction at the same time that the ability to respond may decrease. CONCLUSIONS: The U.S. poliovirus vaccine stockpile remains an important resource that may potentially be needed in the future to respond to an outbreak if a live poliovirus gets imported into a subpopulation with low vaccination coverage.

PROBLEM/CONDITION: Estimated trends in county-level vaccination coverage compared with national health objectives and associated with other variables (e.g., access to care, economic conditions, and demographic characteristics) have not been reported previously. REPORTING PERIOD: 1995-2008. DESCRIPTION OF SYSTEM: The National Immunization Survey (NIS) is an ongoing, random-digit-dialed telephone survey that gathers vaccination coverage data from households with children aged 19-35 months in 50 states and selected urban areas and territories. RESULTS: During 1995-2008, 185,336 children aged 19-35 months sampled by NIS had adequate provider data and lived in one of the 257 counties where the combined sample size for at least one of the seven biennial periods during 1995-2008 was ≥35. Statistically significant increases in estimated vaccination coverage occurred in 27 of 233 counties (12%) with ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis (DTaP); for 38 of 233 counties (16%) with ≥3 doses of polio vaccine; eight of 233 counties (3%) with ≥1 dose of measles, mumps, and rubella (MMR); nine of 233 counties (4%) with ≥3 doses of Haemophilus influenzae type B (Hib) vaccine; 193 of 233 counties (83%) with ≥3 doses of hepatitis B vaccine; 228 of 232 counties (98%) with ≥1 dose of varicella vaccine; and 187 of 192 counties (97%) with ≥4 doses of 7-valent pneumococcal conjugate vaccine (PCV7). Six of 233 (2%) counties had significant decreases in vaccination coverage for Hib. During the 2007-2008 biennial period, the percentage of 193 counties with estimated vaccine coverage that achieved the Healthy People 2010 objective of 90% vaccination coverage was 8% for DTaP/DTP vaccines, 93% for polio vaccine, 86% for MMR vaccine, 71% Hib vaccine, 94% for hepatitis B vaccine, 50% for varicella vaccine, and <1% for PCV7. Among 104 counties, the estimated percentage of children aged 6-23 months who were administered ≥1 dose of the seasonal influenza vaccine during the 2007-2008 influenza vaccination season was 39.0% (range: 22.2%-68.8%). For most vaccines and vaccine series, higher levels of county-level vaccination coverage correlated with a higher number of pediatricians per capita, a higher number of people living in group quarters (e.g., college residence halls, residential treatment centers, skilled nursing facilities, group homes, military barracks, correctional facilities, workers' dormitories, and facilities for persons experiencing homelessness) per capita, higher per capita income, a higher number of Hispanics per capita, and having a service-dependent economy. Lower levels of county-level vaccination coverage correlated with higher number of persons in poverty per capita, a higher percentage of black children among children aged <5 years, higher levels of housing stress (i.e., ≥30% income for rent or mortgage and certain inadequate housing characteristics), a higher number of pediatric intensive care beds per capita, and designation as a nonmetropolitan county with an economy dependent on recreation activities. INTERPRETATION: During 1995-2008, significant increases in vaccination coverage for individual vaccines occurred in many counties for the newly recommended vaccines, varicella and PCV7. PUBLIC HEALTH ACTIONS: In counties that did not meet the Healthy People 2010 vaccination coverage objectives, states should evaluate strategies to achieve these objectives. The Guide to Community Preventive Services provides a summary of interventions that increase community vaccination coverage, including provider reminder-recall systems that remind parents to return to clinics to administer missed doses to children and assessment and feedback on the performance of vaccination providers. In counties where significant decreases in Hib vaccination coverage occurred, additional research is warranted to determine whether the recent shortage in the Hib vaccine was the sole cause of these decreases. In counties with a high proportion of children living in poverty, interventions to increase vaccination coverage among these children are needed. Additional research is required to understand potential barriers to increased coverage with these vaccines, the role of vaccination providers and their resource constraints, and factors associated with access to health care among children.

OBJECTIVES: We compared (1) characteristics of adolescents who are and are not entitled to receive free vaccines from the Vaccines for Children (VFC) program and (2) vaccination coverage with meningococcal conjugate (MCV4), quadrivalent human papillomavirus (HPV4), and tetanus-diphtheria-acellular pertussis (Tdap) vaccines among VFC-eligible and non-VFC-eligible adolescents. METHODS: We analyzed data from the 2009 National Immunization Survey-Teen, a nationally representative, random-digit-dialed survey of households with adolescents aged 13-17 years (n = 20,066). Differences in sociodemographic characteristics and provider-reported vaccination coverage were evaluated using t-tests. RESULTS: Overall, 32.1% (+/- 1.2%) of adolescents were VFC-eligible. VFC-eligible adolescents were significantly less likely than non-VFC-eligible adolescents to be white and to live in suburban areas, and more likely to live in poverty and to have younger and less educated mothers. Nationally, coverage among non-VFC-eligible adolescents was 57.1% (+/-1.5%) for > or = 1 dose of Tdap, 55.4% (+/-1.5%) for > or = 1 dose of MCV4, and 43.2% (+/- 2.2%) for > or = 1 dose of HPV4. Coverage among VFC-eligible adolescents was 52.5% (+/- 2.4%) for > or = 1 dose of Tdap, 50.1% (+/- 2.4%) for > or = 1 dose of MCV4, and 46.6% (+/- 3.5%) for > or =1 dose of HPV4. Only 27.5% (+/- 1.8%) of non-VFC-eligible adolescents and 25.0% (+/- 2.9%) of VFC-eligible adolescents received > or = 3 doses of HPV4. Vaccination coverage was significantly higher among non-VFC-eligible adolescents for Tdap and MCV4, but not for one-dose or three-dose HPV4. CONCLUSIONS: Coverage with some recommended vaccines is lower among VFC-eligible adolescents compared with non-VFC-eligible adolescents. Continued monitoring of adolescent vaccination rates, particularly among VFC-eligible populations, is needed to ensure that all adolescents receive all routinely recommended vaccines.

OBJECTIVES: Following the measles outbreaks of the late 1980s and early 1990s, vaccination coverage was found to be low nationally, and there were pockets of underimmunized children primarily in inner cities. We described the percentage and demographics of children who were entitled to the Vaccines for Children (VFC) program in 2009 and evaluated whether Healthy People 2010 (HP 2010) vaccination coverage objectives of 90% were achieved among these children. METHODS: We analyzed data from 16,967 children aged 19-35 months sampled by the National Immunization Survey in 2009. VFC-entitled children included children who were (1) on Medicaid, (2) not covered by health insurance, (3) of American Indian/Alaska Native race/ethnicity, or (4) covered by private health insurance that did not pay all of the costs of vaccines, but who were vaccinated at a Federally Qualified Health Center or a Rural Health Center. RESULTS: An estimated 49.7% of all children aged 19-35 months were entitled to VFC vaccines. Compared with children who did not qualify for VFC, the VFC-entitled children were significantly more likely to be Hispanic or non-Hispanic black; to have a mother who was widowed, divorced, separated, or never married; and to live in a household with an annual income below the federal poverty level. Mothers of VFC-entitled children were significantly less likely to have some college experience or to be college graduates. Of nine vaccines analyzed, two vaccines--polio at 91.7% and hepatitis B at 92.2%--achieved the HP 2010 90% coverage objective for VFC-entitled children, and four others, including measles-mumps-rubella at 88.8%, achieved greater than 80% coverage. CONCLUSIONS: Today, children with demographic characteristics like those of children who were at the epicenter of the measles outbreaks two decades ago are entitled to VFC vaccines at no cost, and have achieved high vaccination coverage levels.

OBJECTIVE: We evaluated the association between parents' beliefs about vaccines, their decision to delay or refuse vaccines for their children, and vaccination coverage of children at aged 24 months. METHODS: We used data from 11,206 parents of children aged 24-35 months at the time of the 2009 National Immunization Survey interview and determined their vaccination status at aged 24 months. Data included parents' reports of delay and/or refusal of vaccine doses, psychosocial factors suggested by the Health Belief Model, and provider-reported up-to-date vaccination status. RESULTS: In 2009, approximately 60.2% of parents with children aged 24-35 months neither delayed nor refused vaccines, 25.8% only delayed, 8.2% only refused, and 5.8% both delayed and refused vaccines. Compared with parents who neither delayed nor refused vaccines, parents who delayed and refused vaccines were significantly less likely to believe that vaccines are necessary to protect the health of children (70.1% vs. 96.2%), that their child might get a disease if they aren't vaccinated (71.0% vs. 90.0%), and that vaccines are safe (50.4% vs. 84.9%). Children of parents who delayed and refused also had significantly lower vaccination coverage for nine of the 10 recommended childhood vaccines including diphtheria-tetanus-acellular pertussis (65.3% vs. 85.2%), polio (76.9% vs. 93.8%), and measles-mumps-rubella (68.4% vs. 92.5%). After adjusting for sociodemographic differences, we found that parents who were less likely to agree that vaccines are necessary to protect the health of children, to believe that their child might get a disease if they aren't vaccinated, or to believe that vaccines are safe had significantly lower coverage for all 10 childhood vaccines. CONCLUSIONS: Parents who delayed and refused vaccine doses were more likely to have vaccine safety concerns and perceive fewer benefits associated with vaccines. Guidelines published by the American Academy of Pediatrics may assist providers in responding to parents who may delay or refuse vaccines.

The articles published in this special supplement of Public Health Reports provide examples of only some of the current efforts in the United States for evaluating vaccination coverage. So, how did we get here? The history of vaccination and assessment of vaccination coverage in the U.S. has its roots in the pre-Revolutionary War era. In many cases, development of vaccines, and attention devoted to the assessment of vaccination coverage, has grown from the impact of infectious disease on major world events such as wars. The purpose of this commentary is to provide a brief overview of the key historical events in the U.S. that influenced the development of vaccines and the efforts to track vaccination coverage, which laid the foundation for contemporary vaccination assessment efforts.

Random-digit-dial telephone surveys are experiencing both declining response rates and increasing under-coverage due to the prevalence of households that substitute a wireless telephone for their residential landline telephone. These changes increase the potential for bias in survey estimates and heighten the need for survey researchers to evaluate the sources and magnitudes of potential bias. We apply a Monte Carlo simulation-based approach to assess bias in the NIS, a land-line telephone survey of 19-35 month-old children used to obtain national vaccination coverage estimates. We develop a model describing the survey stages at which component nonsampling error may be introduced due to nonresponse and under-coverage. We use that model and components of error estimated in special studies to quantify the extent to which noncoverage and nonresponse may bias the vaccination coverage estimates obtained from the NIS and present a distribution of the total survey error. Results indicated that the total error followed a normal distribution with mean of 1.72 per cent (95 per cent CI: 1.71, 1.74 per cent) and final adjusted survey weights corrected for this error. Although small, the largest contributor to error in terms of magnitude was nonresponse of immunization providers. The total error was most sensitive to declines in coverage due to cell phone only households. These results indicate that, while response rates and coverage may be declining, total survey error is quite small. Since response rates have historically been used to proxy for total survey error, the finding that these rates do not accurately reflect bias is important for evaluation of survey data. Published in 2011 by John Wiley & Sons, Ltd.

OBJECTIVES: We evaluated the association between intentional delay of vaccine administration and timely vaccination coverage. METHODS: We used data from 2,921 parents of 19- to 35-month-old children that included parents' reports of intentional delay of vaccine administration. Timely vaccination was defined as administration with > or = 4 doses of diphtheria, tetanus, and pertussis; > or = 3 doses of polio vaccine; > or = 1 dose of measles, mumps, and rubella vaccine; > or = 3 doses of Haemophilus influenzae type b vaccine; > or = 3 doses of hepatitis B vaccine; and > or = 1 dose of varicella vaccine by 19 months of age, as reported by vaccination providers. RESULTS: In all, 21.8% of parents reported intentionally delaying vaccinations for their children. Among parents who intentionally delayed, 44.8% did so because of concerns about vaccine safety or efficacy and 36.1% delayed because of an ill child. Children whose parents intentionally delayed were significantly less likely to receive all vaccines by 19 months of age than children whose parents did not delay (35.4% vs. 60.1%, p < 0.05). Parents who intentionally delayed were significantly more likely to have heard or read unfavorable information about vaccines than parents who did not intentionally delay (87.6% vs. 71.9%, p < 0.05). Compared with parents who intentionally delayed only because their child was ill, parents who intentionally delayed only because of vaccine safety or efficacy concerns were significantly more likely to seek additional information about their decision from the Internet (11.4% vs. 1.1%, p < 0.05), and significantly less likely to seek information from a doctor (73.9% vs. 93.9%, p < 0.05). CONCLUSIONS: Intentionally delayed vaccine doses are not uncommon. Children whose parents delay vaccinations may be at increased risk of not receiving all recommended vaccine doses by 19 months of age and are more vulnerable to vaccine-preventable diseases. Providers should consider strategies such as educational materials that address parents' vaccine safety and efficacy concerns to encourage timely vaccination.

STUDY OBJECTIVE: Influenza causes significant widespread illness each year. Emergency department (ED) clinicians are often first-line providers to evaluate and make treatment decisions for patients presenting with influenza. We sought to better understand ED clinician testing and treatment practices in the Emerging Infections Program Network, a federal, state, and academic collaboration that conducts active surveillance for influenza-associated hospitalizations. METHODS: During 2007, a survey was administered to ED clinicians who worked in Emerging Infections Program catchment area hospitals' EDs. The survey encompassed the role of the clinician, years since completing clinical training, hospital type, influenza testing practices, and use of antiviral medications during the 2006 to 2007 influenza season. We examined factors associated with influenza testing and antiviral use. RESULTS: A total of 1,055 ED clinicians from 123 hospitals responded to the survey. A majority of respondents (85.3%; n=887) reported they had tested their patients for influenza during the 2006 to 2007 influenza season (Emerging Infections Program site range: 59.3 to 100%; P<.0001). When asked about antiviral medications, 55.7% (n=576) of respondents stated they had prescribed antiviral medications to some of their patients in 2006 to 2007 (Emerging Infections Program site range 32.9% to 80.3%; P<.0001). A positive association between influenza testing and prescribing antiviral medications was observed. Additionally, the type of hospital, location in which an ED clinician worked, and the number of years since medical training were associated with prescribing antiviral influenza medications. CONCLUSION: There is much heterogeneity in clinician-initiated influenza testing and treatment practices. Additional exploration of the role of hospital testing and treatment policies, clinicians' perception of influenza disease, and methods for educating clinicians about new recommendations is needed to better understand ED clinician testing and treatment decisions, especially in an environment of rapidly changing influenza clinical guidelines. Until influenza testing and treatment guidelines are better promulgated, clinicians may continue to test and treat influenza with inconsistency.

OBJECTIVE: The goal was to explore the association of being underinsured and receiving doses at a health department clinic (HDC) with not receiving all recommended adolescent vaccine doses. METHODS: A total of 5657 adolescents, 13 to 17 years of age, were sampled in the National Immunization Survey-Teen in 2006-2007. RESULTS: A total of 63.9% of all adolescents were covered by private health insurance. Among privately insured adolescents, [similar to]31.3% were underinsured. Compared with fully insured adolescents, underinsured adolescents were more likely to receive doses at an HDC for tetanus-diphtheria toxoids/tetanus toxoids-reduced diphtheria toxoids-acellular pertussis vaccine (25.1% vs 6.2%; P < .05), tetravalent meningococcal conjugate vaccine (11.5% vs 2.5%; P < .05), and quadrivalent human papillomavirus vaccine (16.2% vs 3.4%; P < .05). Also, compared with fully insured adolescents, underinsured adolescents who received doses at an HDC had lower estimated rates of vaccination coverage for tetanus-diphtheria toxoids/tetanus toxoids-reduced diphtheria toxoids-acellular pertussis vaccine (58.5% vs 70.9%; P < .05), tetravalent meningococcal conjugate vaccine (10.8% vs 25.8%; P < .05), and quadrivalent human papillomavirus vaccine (7.8% vs 14.3%; P < .05). CONCLUSION: Underinsured adolescents who receive doses at an HDC have lower rates of vaccination coverage than do fully insured adolescents. Copyright copyright 2009 by the American Academy of Pediatrics.

BACKGROUND: Underinsured children are covered by private health insurance that does not cover the cost of vaccines, are not entitled to receive publicly purchased vaccines at no cost through the Vaccines for Children (VFC) Program unless they receive doses at a Federally Qualified Health Center (FQHC) or a Rural Health Center (RHC), may be referred by their primary care providers to health department clinics (HDCs) for vaccinations, and may have lower vaccination coverage for new and more expensive vaccines. OBJECTIVES: To describe the estimated percentage of children in the U.S. who are underinsured, receive vaccine doses at HDCs, and are not VFC-entitled; and to evaluate the association between being underinsured, receiving vaccine doses at an HDC, and timely vaccination coverage. METHODS: Subjects were 16 621 19-35 month-old children sampled by the National Immunization Survey in 2007. RESULTS: Of all 19-35 month-old children, an estimated 10.5% were underinsured; and an estimated 1.4% were underinsured, received doses at an HDC, and were not VFC-entitled. Compared to fully insured children, children who were underinsured and received doses at an HDC had significantly lower vaccination coverage for the varicella (81.5% vs. 87.7%, p < 0.05) and PCV7 (55.1% vs. 75.9%, p < 0.05) vaccines. CONCLUSIONS: Children who were underinsured and received doses at HDCs were found to have lower estimated timely vaccination coverage for recently recommended vaccines and more expensive varicella and PCV7 vaccines. To adequately vaccinate these children at HDCs, states require stable funding to pay for vaccines as the number of new and more expensive vaccines grows. Copyright copyright 2009 by the American Academy of Pediatrics.

BACKGROUND: Changes in invasive pneumococcal disease (IPD) incidence were evaluated after 7 years of 7-valent pneumococcal conjugate vaccine (PCV7) use in US children. METHODS: Laboratory-confirmed IPD cases were identified during 1998-2007 by 8 active population-based surveillance sites. We compared overall, age group-specific, syndrome-specific, and serotype group-specific IPD incidence in 2007 with that in 1998-1999 (before PCV7) and assessed potential serotype coverage of new conjugate vaccine formulations. RESULTS: Overall and PCV7-type IPD incidence declined by 45% (from 24.4 to 13.5 cases per 100,000 population) and 94% (from 15.5 to 1.0 cases per 100,000 population), respectively (P< .01 all age groups). The incidence of IPD caused by serotype 19A and other non-PCV7 types increased from 0.8 to 2.7 cases per 100,000 population and from 6.1 to 7.9 cases per 100,000 population, respectively (P< .01 for all age groups). The rates of meningitis and invasive pneumonia caused by non-PCV7 types increased for all age groups (P< .05), whereas the rates of primary bacteremia caused by these serotypes did not change. In 2006-2007, PCV7 types caused 2% of IPD cases, and the 6 additional serotypes included in an investigational 13-valent conjugate vaccine caused 63% of IPD cases among children <5 years-old. CONCLUSIONS: Dramatic reductions in IPD after PCV7 introduction in the United States remain evident 7 years later. IPD rates caused by serotype 19A and other non-PCV7 types have increased but remain low relative to decreases in PCV7-type IPD.

OBJECTIVES: To evaluate trends in national vaccination coverage from 2000 to 2007 among children aged 19-35 months for at least four doses of diphtheria-tetanus-pertussis vaccine (4+DTaP), three doses of poliovirus vaccine (3+Polio), one dose of measles-mumps-rubella vaccine (1+MMR), three doses of Haemophilus influenzae type b vaccine (3+Hib), three doses of hepatitis B vaccine (3+HepB), one dose of Varicella vaccine (1+Var), and the standard vaccine series of these six vaccines (4:3:1:3:3:1). To predict vaccination coverage levels in 2008-2010 for those vaccines that have not yet reached the Healthy People 2010 coverage targets of 90% for individual vaccines and 80% for the vaccine series. METHODS: Data were analyzed for 167,086 children aged 19-35 months in the 2000-2007 National Immunization Survey. Vaccination coverage trends were analyzed with weighted least squares linear regression models. Nonlinear Weibull and logarithmic regression models were fitted to these past results, and extrapolation was used to predict vaccination coverage levels for 4+DTaP, 1+Var, and the 4:3:1:3:3:1 series from 2008 to 2010. RESULTS: From 2000 to 2007, observed vaccination coverage increased significantly for four of the six vaccines and the standard vaccine series, and reached the 90% target for 3+Polio, 1+MMR, 3+Hib, and 3+HepB. Increases in coverage were not significant for 1+MMR and 3+Hib; however, coverage for these vaccines was consistently>90% throughout the study period. Both Weibull and logarithmic regression models predicted that coverage with 1+Var and the 4:3:1:3:3:1 series will surpass the 2010 target by 2008, while coverage with 4+DTaP will fall short of the target at 86% in 2010. CONCLUSIONS: The United States is well on the way toward reaching most of the Healthy People 2010 objectives for early childhood vaccination coverage. Enhanced efforts are needed to ensure that these trends continue, and to increase coverage with 4+DTaP.