Fifty-five percent of preteens had at least one vaccination visit at ages 11-12 years in a 2009 Centers for Disease Control and Prevention survey, but they often did not receive all vaccines indicated for this age group.

In 1996, the Centers for Disease Control and Prevention (CDC) recommended that physicians administer tetanus-diphtheria (Td) vaccine to 11- and 12-year-olds. Between 2005 and 2008, the CDC recommendations for this population also include meningococcal conjugate vaccine (MCV4), a booster dose of tetanus and diphtheria toxoids with acellular pertussis (Tdap) vaccine, quadrivalent human papillomavirus (HPV) vaccine for girls, influenza vaccine, and, for some adolescents, a second dose of varicella vaccine.

So Shannon Stokley, M.P.H., of the CDC Immunization Services Division, and her colleagues examined data from the 2009 National Immunization Survey–Teen (NIS-Teen) telephone interview to estimate vaccination coverage rates for adolescents aged 13-17 years. Although significantly more preteens and adolescents are being vaccinated than indicated in previous studies, estimates from previous studies did not reflect the specific ages at which the individuals received the vaccines.

A series of vaccinations have been recommended by the CDC for 11- and 12-year-olds, but most preteens aren’t receiving them all.

NIS-Teen, conducted between Jan. 6, 2009, and Feb. 10, 2010, used random-digit dialing to survey households with age-eligible adolescents and, with consent, mailed an Immunization History Questionnaire to providers. The researchers completed interviews with 35,004 households and obtained information from vaccine providers for 20,066 children and adolescents, Ms. Stokley and her coauthors reported in the September issue of Archives of Pediatric and Adolescent Medicine (2011;165:813-8).

The investigators assessed the immunization rates for measles, hepatitis B, and varicella, as well as Td/Tdap and meningococcal-containing vaccines, for all children and adolescents and for specific age groups, and they also assessed HPV vaccination for girls. They determined the age at which each child or adolescent received each dose of vaccine, and the percentage of adolescents aged 11-12 years who made at least one vaccination visit.

Outcome measures included being up-to-date with recommended vaccines by age 11 years, by age 13 years, and at the time of the interview (ages 13 and older).

Analysis of the data showed the following:

• Td/Tdap vaccine. The researchers found that 6.1% of preteens received Td/Tdap vaccine by age 11. Vaccination with Td/Tdap during ages 11-12 years increased with each birth cohort; receipt of a Td and/or Tdap vaccine at ages 11-12 years more than doubled, from 33.8% among those born in 1991 to 68.2% for those born in 1996. Coverage increased an additional 42.1% by age 13 years and an additional 28.9% by the time of the interview.

• MCV4: The number of patients who received MCV4 increased from 8.4% in the 1993 birth cohort (the first cohort for whom it was available) to 50.0% in 1996 birth cohort. Overall, 18.6% of the sample received the vaccine by age 13.

• HPV: The number of girls who received the HPV vaccine at ages 11-12 years increased significantly, from 11.1% of those born in 1994 (the first birth cohort for whom it was available) to 30.5% of those born in 1996. By age 13, 10.9% of the population studied had received the vaccine.

Although 55% of preteen patients had at least one vaccination visit at ages 11-12 years, 19.5% of the preteens who made a vaccination visit at this age and were eligible for vaccination did not receive Td and/or Tdap vaccines, 60.9% did not receive meningococcal-containing vaccines, and 62.4% of girls did not receive HPV vaccines. Recent surveys have shown that physicians are reluctant to administer the HPV and MCV4 at these ages, but the data in this analysis show that vaccination rates at this age may be increasing, Ms. Stokley and her associates reported.

"Our analysis of the early stages of adolescent vaccine implementation show encouraging progress with implementing the new recommendations, but also indicate that more can be done to increase the frequency with which adolescents receive all necessary vaccines during a visit," the researchers said.

Some suggestions they offer:

• Educate parents about recommended vaccines and the diseases they prevent, as well as the benefits of preventive health care visits.

• Work with immunization providers to encourage them to take advantage of all health care encounters to administer all vaccines for which an adolescent is eligible during the same visit.

Potential limitations of this study include bias due to household nonresponse and households not having landlines, exclusion of adolescents for whom there was not adequate immunization data, and possible misclassification of adolescents as not having received all vaccines if all providers were not identified.

The CDC offers information for parents (www.cdc.gov/vaccines/who/teens/index.html) and for health care providers (www.cdc.gov/vaccines/who/teens/for-hcp.html).

Ms. Stokley and her associates had no relevant financial disclosures.

More Preteens Get Vaccinations, But Not All They Need