National and State Vaccination Coverage Among Adolescents Aged 13–17 Years — United States, 2011

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Since 2005, the Advisory Committee on Immunization Practices (ACIP) has expanded the routine adolescent vaccination schedule with administration of the following vaccines at ages 11 or 12 years: meningococcal conjugate (MenACWY), 2 doses*; tetanus, diphtheria, acellular pertussis (Tdap), 1 dose; human papillomavirus (HPV), 3 doses; and influenza, 1 dose annually (1). To assess vaccination coverage among adolescents aged 13–17 years,† CDC analyzed data from the National Immunization Survey-Teen (NIS-Teen). This report summarizes the results of that assessment, which indicated that, from 2010 to 2011, vaccination coverage increased for ≥1 dose Tdap on or after age 10 years (from 68.7% to 78.2%), ≥1 dose MenACWY (from 62.7% to 70.5%), and, among females, for ≥1 dose of HPV (from 48.7% to 53.0%) and ≥3 doses of HPV§ (from 32.0 to 34.8%) (2). Vaccination coverage varied widely among states. Interventions that increase adolescent vaccination coverage include strong recommendations from health-care providers, urging consideration of every health visit as an opportunity for vaccination, reducing out-of-pocket costs, and using reminder/recall systems. Despite increasing adolescent vaccination coverage, the percentage point increase in ≥1 dose HPV coverage among adolescent females was less than half that of the increase in ≥1 dose of Tdap or MenACWY. The causes of lower coverage with HPV vaccine are multifactorial; addressing missed opportunities for vaccination, as well as continued evaluation of vaccination-promoting initiatives, is needed to protect adolescents against HPV-related cancers.

NIS-Teen collects vaccination information for adolescents aged 13–17 years in the 50 states, the District of Columbia, selected areas,¶ and the U.S. Virgin Islands,** using a random-digit–dialed sample of landline and, starting in 2011, cellular telephone numbers.†† Parent/guardian respondents provide vaccination and sociodemographic information on adolescents in their care. After the parent/guardian grants permission to contact their child's vaccination provider, a questionnaire is mailed to that provider to obtain a vaccination history from the medical record.§§ A total of 23,564 adolescents (12,328 males and 11,236 females) are included in the national estimates.¶¶ NIS-Teen methodology, including weighting procedures, has been described previously.*** Differences in vaccination coverage were evaluated using t-tests and were considered statistically significant at p≤0.05.

National Vaccination Coverage

Adolescent vaccination coverage increased from 2006 to 2011, although the rate of increase differed by vaccine (Figure). The average annual percentage point increase from 2007 to 2010 was 12.8 (95% confidence interval [CI] = 11.9–13.6) for ≥1 dose of Tdap, 10.1 (CI = 9.3–10.9) for ≥1 dose of MenACWY, and among females, 7.9 (CI = 6.7–9.0) for ≥1 dose of HPV. The percentage point increase from 2010 to 2011 was 9.5 for ≥1 dose of Tdap, 7.8 for ≥1 dose of MenACWY, 4.3 for ≥1 dose and 2.8 for ≥3 doses of HPV among females, and 6.9 for ≥1 dose of HPV among males (Table 1). Among females and males who initiated the HPV series, 70.7% and 28.1% received 3 doses, respectively. Coverage with measles, mumps, and rubella (MMR) and hepatitis B (HepB) vaccines remained above 90%, and 2-dose varicella vaccine coverage was 68.3%. No significant differences were observed in vaccination coverage among males and females, except for vaccination with HPV (Table 1) and ≥2 doses of varicella vaccine (males [70.3%], females [66.1%]; p<0.01).†††

Vaccination Coverage by Age, Race/Ethnicity, and Poverty Status

Compared with adolescents aged 13 years, coverage with ≥1 dose of Tdap, ≥3 doses of HepB, and ≥2 doses of MMR was significantly lower among adolescents aged 17 years. Coverage with ≥1 and ≥2 doses of varicella was significantly lower among adolescents aged 15–17 years compared with those aged 13 years. Vaccination coverage increased with age for ≥1 and ≥3 HPV doses among females, with coverage significantly lower among females aged 13 years compared with those aged 14–17 years. Coverage with ≥1 dose of Tdap was higher for Asians compared with whites and lower for those living below the federal poverty level§§§ compared with those living at or above poverty level (Table 2). For ≥1 dose of MenACWY, coverage was higher for blacks, Hispanics, and Asians compared with whites; no differences were observed in coverage by poverty status.

For HPV, patterns differed by racial/ethnic group and poverty status depending upon the measure of HPV vaccination (Table 2). Among females and males, HPV initiation was higher for blacks and Hispanics compared with whites; coverage with ≥3 HPV doses was higher for Hispanics compared with whites. However, among females, completion of the HPV series among those who had started it was lower for blacks compared with whites. Among females and males, coverage with ≥1 and ≥3 HPV doses was higher for those living below poverty level compared with those living at or above poverty level; however, among females, HPV series completion was lower among those living below poverty level compared with those living at or above poverty level.

Healthy People 2020 Targets

The Healthy People 2020 targets for vaccination coverage of adolescents aged 13–15 years are 80.0% for ≥1 dose of Tdap, ≥1 dose MenACWY, ≥3 doses of HPV (among females), and 90.0% for ≥2 doses of varicella vaccine (3). Vaccination coverage in 2011 was 80.5% (CI = 79.2–81.6) for ≥1 dose of Tdap, 71.5% (CI = 70.1–72.8) for ≥1 dose of MenACWY, 30.0% (CI = 28.0–32.1) for ≥3 doses of HPV (among females), and 71.8% (CI = 70.1–73.4) for ≥2 doses of varicella vaccine.¶¶¶

State Vaccination Coverage

Coverage estimates for ≥1 dose of Tdap ranged from 36.9% (Mississippi) to 95.0% (New Hampshire), and for ≥1 dose of MenACWY, from 27.6% (Arkansas) to 92.1% (Indiana) (Table 3). Among females, coverage for ≥1 dose of HPV varied from 31.9% (Mississippi) to 76.1% (Rhode Island), and for ≥3 doses of HPV, from 15.5% (Arkansas) to 56.8% (Rhode Island). Compared with the Northeast and West, the South had significantly lower vaccination rates for ≥1 dose of Tdap, ≥1 dose of MenACWY, and among females, ≥1 and ≥3 doses of HPV. Among females, the difference in coverage estimates, or coverage gap, between the vaccine with the highest coverage (either Tdap or MenACWY) and coverage with ≥1 dose of HPV was 25.3 percentage points nationally and varied widely by state and reporting area, ranging from -0.6 (Hawaii) to 49.4 (New York [excluding New York City]) percentage points (Table 3). The coverage gap between the vaccine with the highest and lowest coverage (either Tdap or MenACWY)**** among males was 6.8 percentage points nationally and also varied widely by state and reporting area, ranging from 0.4 (Georgia) to 48.2 (Montana) percentage points.

Reported by

Christina Dorell, MD, Shannon Stokley, MPH, David Yankey, MS, Jenny Jeyarajah, MS, Immunization Services Div; Jessica MacNeil, MPH, Div of Bacterial Diseases, National Center for Immunization and Respiratory Diseases; Lauri Markowitz, MD, Div of Sexually Transmitted Diseases, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC. Corresponding contributor: Christina Dorell, cdorell@cdc.gov, 404-639-5198.

Editorial Note

Adolescent vaccination coverage increased from 2010 to 2011, with Tdap coverage reaching the Healthy People 2020 target of 80%. Coverage with MMR and HepB vaccines remained above 90%, and 2-dose varicella vaccine coverage had a 10 percentage point increase since 2010. However, the percentage-point increase in ≥1 dose of HPV among females was half the increase observed for ≥1 dose of Tdap and ≥1 dose of MenACWY for the third consecutive year. Among males, coverage with ≥1 dose of HPV increased 6.9 percentage points in 2011 and reflects receipt of vaccination as a result of the 2009 ACIP guidance stating that HPV vaccination could be administered to males aged 9–26 years.††††

Despite higher coverage with the Tdap, MMR, HepB, and varicella vaccines among younger compared with older adolescents, coverage with ≥1 dose of HPV was higher among older compared with younger adolescents. Although not evaluated in this analysis, parental delay of HPV vaccination of adolescent girls has been associated with lower vaccination rates (4,5). Additionally, fewer and weaker health-care provider recommendations for the HPV vaccine to younger adolescents most likely contribute to lower vaccination rates (6). As in previous years, Hispanic and black females had higher coverage with ≥1 dose of HPV compared with white females (2). Risk-based approaches that base health-care provider recommendations for HPV on the perceived level of the patient's risk for cervical cancer might contribute to higher HPV initiation rates among blacks and Hispanics (7). Hispanic females were more likely than white females to be fully protected with 3 doses of HPV, and females living below the poverty line were more likely to be fully protected than those living at or above poverty. HPV series completion rates demonstrate the extent and timeliness of the receipt of 3 doses of HPV among those who initiated the series. Among females with adequate time to complete the series, 29.3% had not done so. Despite equal or higher 3-dose HPV coverage among blacks and those living below poverty, HPV series completion rates were lower among these populations known to have higher cervical cancer rates (8). Reminder/recall systems and the use of every office visit to administer needed vaccinations could improve HPV completion rates within the recommended dosing intervals.

Vaccination estimates continue to vary widely by state and vaccine. The number of states with middle school enrollment vaccination requirements increased from the 2010–11 school year, when 31 states required Tdap, 19 required MenACWY, and 42 required varicella, to the 2011–12 school year, when 36 states required Tdap, 19 required MenACWY, and 43 required varicella. These new state requirements might have contributed to increased coverage for these vaccines (9). Despite the publication of routine recommendations for Tdap, MenACWY, and HPV vaccination of adolescents within 2 years of one another (2005–2007), large coverage gaps persist between Tdap, MenACWY, and HPV among females and between Tdap and MenACWY among males in many states. Large coverage gaps demonstrate achievable coverage if all recommended vaccines were given simultaneously and missed vaccination opportunities were decreased.

The findings in this report are subject to at least four limitations. First, the cellular phone household response rate was only 22.4%, and the landline household response rate was 57.2%. Only 54.6% (cellular telephones phone) and 61.5% (landline) of those with completed household interviews also had adequate vaccination provider data. Differences between national coverage estimates from landline only and dual-frame (both landline and cellular telephone household) samples were small, ranging from -1.2 to 2.7 percentage points. Nonresponse and noncoverage (from exclusion of households without telephones) bias might remain after weighting adjustments; a total survey error model based on data from vaccination provider–reported vaccination coverage rates from the National Health Interview Survey estimated 2010 NIS-Teen estimates were 4–5 percentage points higher for Tdap and MenACWY and 1 percentage point higher for HPV initiation among females.§§§§ Second, underestimates of vaccination coverage might have resulted from the exclusive use of vaccination provider–verified vaccination histories because the completeness of these records is unknown. Third, estimates for particular states and reporting areas and for racial/ethnic populations should be interpreted with caution because of smaller sample sizes and wider CIs. Finally, smaller sample sizes of females might result in less power to detect differences in HPV coverage by state.

The Healthy People 2020 objective for ≥1 dose of Tdap was achieved in 2011, with 80.5% coverage among adolescents aged 13–15 years, demonstrating that high vaccination rates with vaccines recommended for adolescents are achievable. Promoting health-care provider recommendations and parental awareness of adolescent vaccines, urging consideration of every health visit as an opportunity for vaccination, reducing out-of-pocket costs, and using immunization information systems and reminder/recall systems can increase vaccination among adolescents (10). Continued vaccination surveillance and assessment of hesitancy among parents are needed to better understand characteristics associated with the delay or refusal of adolescent vaccines, especially the HPV vaccine. Increasing HPV series completion among those who initiate the vaccine is also needed. Finally, state and local immunization programs should make adolescent vaccination a priority and implement initiatives aimed at decreasing coverage gaps.

References

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