National Vaccination Coverage Among Adolescents Aged 13--17 Years --- United States, 2006

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Before 2005, vaccines were administered during adolescence to "catch up"* children with vaccinations not received at a younger age, with the exception of the tetanus and diphtheria (Td) booster (1). However, since 2005, three new vaccines specifically for older children have been licensed and recommended in the United States: meningococcal conjugate vaccine (MCV4) for those aged 11--12 years and 15 years; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine for those aged 11--12 years (or at ages 13--18 years if not received at ages 11--12 years); and human papillomavirus (HPV) vaccine for girls aged 11--12 years (or at ages 13--18 years if not received at 11--12 years). Since 1996, the Advisory Committee on Immunization Practices (ACIP) and professional organizations, including the American Academy of Pediatrics (AAP), the American Academy of Family Physicians (AAFP), and the American Medical Association (AMA), have recommended a health-care visit at ages 11--12 years for receipt of recommended vaccinations (2). In addition, a Healthy People 2010 objective (14-27) is to achieve >90% vaccination coverage among adolescents aged 13--15 years (3) for certain vaccines.^§ In 2006, for the first time, the National Immunization Survey (NIS) collected provider-reported vaccination information for adolescents aged 13--17 years (NIS-Teen). This report describes the results of that survey, which indicated that the Healthy People 2010 target has not been met for any of the vaccines analyzed. HPV vaccination coverage is not included in this report because NIS-Teen was conducted before HPV vaccination recommendations were published in March 2007. Routine health-care visits for adolescents should be encouraged, with emphasis on a visit at ages 11--12 years, and providers should continue to assess the need for vaccinations at every opportunity. NIS-Teen will be conducted annually to monitor coverage with recommended vaccines during ages 11--17 years and to identify groups with lower coverage.

NIS, which traditionally monitors vaccination coverage for children aged 19--35 months, has been conducted by CDC since 1994. NIS-Teen is a random-digit--dialed telephone survey that collects vaccination information using methods similar to those of NIS, including use of vaccination records from health-care providers to determine vaccination coverage estimates (4,5). During October 2006--February 2007, a total of 5,468 household interviews were conducted with parents or guardians of adolescents aged 13--17 years.^¶ The household response rate was 56.2%; a total of 2,882 adolescents with provider-reported vaccination records were included in this report, representing 52.7% of adolescents with completed household interviews.

Coverage with >1 dose of either Td or Tdap vaccine after age 10 years was 60.1% (95% confidence interval [CI] = 57.8--62.4) (Table). Overall vaccination coverage with Td vaccine was 49.4% (CI = 47.0--51.7) and ranged from 35.7% among adolescents aged 13 years to 63.5% among those aged 17 years. In 2005, Tdap vaccine was licensed and recommended to replace a single dose of Td vaccine. Coverage with 1 dose of Tdap vaccine was 10.8% (CI = 9.4--12.3) and ranged from 5.1% among adolescents aged 17 years to 15.4% among those aged 14 years.

Coverage with >3 doses of hepatitis B vaccine among all adolescents aged 13--17 years was 81.3% (CI = 79.4--83.1); coverage was higher among adolescents aged 13--14 years than among those aged 15--17 years (Table). Overall coverage with measles, mumps, and rubella (MMR) vaccine also was high (86.9% [CI = 85.2--88.5]), with no substantial differences by age.

Almost three fourths of adolescents had a history of varicella disease (69.9% [CI = 67.7--72.0]) (by parental report or provider history). Among adolescents without a history of varicella disease, 65.5% (CI = 61.4--69.4) had received >1 dose of varicella vaccine.

MCV4 vaccination had been received by 11.7% (CI = 10.3--13.2) of adolescents aged 13--17 years; the highest coverage was among those aged 15 years (13.9% [CI = 10.9--17.6]). Adolescents aged 17 years had the lowest MCV4 coverage (7.1% [CI = 5.0--10.0]; p<0.05).

To assess progress in achieving Healthy People 2010 objectives (which do not include adolescents aged 16--17 years), vaccination coverage was determined only for adolescents aged 13--15 years. Coverage was 84.3% (CI = 82.0--86.4) for >3 doses of hepatitis B vaccine, 88.5% (CI = 86.4--90.3) for >2 doses of MMR vaccine, and 56.7% (CI = 53.7--59.7) for >1 dose of Td or Tdap booster; coverage was 70.9% (CI = 66.3--75.1) for >1 dose of varicella vaccine among those without a reported history of disease.

To assess receipt of Td or Tdap vaccinations at ages 10--12 years, vaccination coverage was determined for >1 booster dose by the year in which adolescents reached age 13 years. Receipt of Td or Tdap vaccination increased from 22.7% (CI = 18.4--27.6) of children who reached age 13 years in 2002 to 41.7% (CI = 36.4--47.3) of children who reached age 13 years in 2006 (Figure).

Reported by: N Jain, MD, S Stokley, MPH, Immunization Svcs Div, National Center for Immunization and Respiratory Diseases, CDC.

Editorial Note:

This is the first report of national adolescent vaccination-coverage estimates based on provider-reported vaccination histories. The results indicate that in 2006, the Healthy People 2010 target for adolescents aged 13--15 years had not been met for any of the vaccines. Before development of NIS-Teen, national estimates of adolescent vaccination coverage were determined primarily from data collected from the National Health Interview Survey (NHIS), which is based on parental recall rather than provider records. Based on data from the 2003 NHIS, coverage with >2 doses of MMR and >1 dose of Td vaccine among adolescents ages 13--15 years was estimated at >90% (3), higher than the coverage estimates described in this report. Although the reliability of parental recall of adolescent vaccinations has not been studied, studies evaluating parental recall of infant vaccinations have indicated that parents do not accurately recall childhood vaccinations (6,7), emphasizing the need for provider-reported data.

Coverage levels among adolescents must be considered in the context of vaccination programs that existed when the adolescents reached the recommended ages for each vaccine. For example, adolescents aged 13--14 years were born primarily during 1992--1993, or 1--2 years after ACIP recommendations for universal vaccination of infants with hepatitis B vaccine; adolescents aged 15--17 years were born before this recommendation and therefore might be expected to have lower coverage. Although many states have hepatitis B vaccination requirements for middle-school entry, results from NIS-Teen suggest that many older adolescents have not received the vaccination. Therefore, providers should continue to review the vaccination status of adolescent patients to ensure they are fully vaccinated. CDC will conduct additional analyses to better characterize the impact of vaccination programs on adolescent vaccination coverage.

During 2002--2006, an increasing percentage of children were receiving Td or Tdap by age 13 years, as recommended by ACIP; however, overall coverage (60.1%) remained low, and coverage among adolescents aged 13--15 years (56.7%) was still below the national objective of 90%. Tdap coverage alone was low (10.8%), although a low level was expected because Tdap recommendations were published only 1--2 years before this survey was conducted. The lower Tdap vaccination coverage among older adolescents (aged 16--17 years) compared with younger adolescents (aged 13--15 years) might be a result of the time interval required between Td and Tdap vaccinations; Td vaccination coverage increased with age, and a 5-year interval is recommended before administering Tdap vaccine. Alternately, the higher Tdap coverage among younger adolescents might be a reflection of health-care use patterns; younger adolescents are more likely to have preventive health-care visits, when vaccinations are typically administered, than older adolescents (8).

The findings in this report are subject to at least four limitations. First, because NIS-Teen is a telephone survey, adjustments were made for nonresponse and for households without landline telephones; however, some bias might remain. Second, NIS-Teen uses provider-reported vaccination histories and assumes that coverage among adolescents for whom adequate provider data were not available is similar to coverage among adolescents for whom adequate provider data were available, controlling for factors associated with vaccination coverage; this might have resulted in an underestimation or overestimation of vaccination coverage. Third, certain provider-reported vaccination records might not have included all vaccinations received (e.g., vaccinations administered in nontraditional settings such as emergency departments), which might have resulted in an underestimation of vaccination coverage. Finally, the response rates were low (56.2% household response rate and 52.7% response rate for provider-vaccination records from responding households).

Vaccinating adolescents presents numerous challenges. Adolescents do not frequently seek preventive health-care services, some do not have health insurance, and some visit multiple health-care providers and nontraditional providers who vary in vaccination practices (8,9). Routine health-care visits should be encouraged for all adolescents, with an emphasis on the visit at ages 11--12 years as recommended by ACIP, AAP, AAFP, and AMA (2). During this visit, vaccinations and other evidence-based preventive services should be provided. In addition, adolescents aged 13--18 years should be vaccinated with recommended vaccines at the earliest opportunity. CDC will continue annual monitoring of adolescent vaccination coverage among different age groups. Future analyses will assess coverage by race/ethnicity and other sociodemographic factors to identify barriers to vaccination. To increase the ascertainment of provider-reported vaccinations, the 2007 NIS-Teen includes new questions for parents or guardians on vaccinations their adolescents received from providers other than traditional health-care providers. In addition, the survey will be expanded in 2008 to produce state-level estimates that will provide information on the effects of additional factors on adolescent coverage, including vaccine financing and state mandates.

References

* Catch-up can refer either to vaccinations that are administered because they were recommended but missed or vaccinations administered to persons who were born before a particular vaccine became available or before a vaccine was routinely recommended for infants (e.g., hepatitis B, varicella, or measles, mumps, and rubella).

In June 2007, after the National Immunization Survey--Teen interviews included in this report were completed, MCV4 recommendations were simplified to include all persons aged 11--18 years.

^§For >3 doses hepatitis B vaccine; >2 doses measles, mumps, and rubella vaccine; >1 dose Td booster; and >1 dose varicella vaccine among those without a reported history of disease. In addition, the target for any new ACIP-recommended vaccine is >90% coverage within 5 years of the recommendation.

^¶Eligible adolescents included those born during October 7, 1988--February 7, 1994.

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