Vaccination Coverage Among Adolescents 1 Year Before the Institution of a Seventh Grade School Entry Vaccination Requirement — San Diego, California, 1998

Morbidity and Mortality Weekly Report, Feb 11, 2000

In 1996, the Advisory Committee on Immunization Practices, the American Academy of Pediatrics, the American Association of Family Physicians, and the American Medical Association recommended routine health-care visits for children aged 11-12 years, emphasizing vaccination with hepatitis B vaccine; measles, mumps, and rubella vaccine (MMR); tetanus and diphtheria toxoids (Td); and varicella vaccine [1]. Because no national data exist regarding vaccination coverage among adolescents, the impact of these recommendations is unknown. In October 1997, California enacted Assembly Bill 381 (AB381) that requires students entering the seventh grade on or after July 1, 1999, to have received three doses of hepatitis B vaccine and two doses of MMR. To assist in planning and implementing AB381, the San Diego County Health Department expanded its 1998 infant and adult vaccination survey to include fifth and sixth graders. This report summarizes the findings from that survey, which indicate that most fifth and sixth grader s lacked required and recommended vaccinations.

In April 1998, San Diego County households were sampled randomly by telephone. For households in which children entering the fifth or sixth grade resided, parents who agreed to participate in the survey were asked to use their parent-held vaccination record to report their child's vaccination history. If a parent-held record could not be located, parents were asked to recall which vaccinations the child had received. All participating parents were asked for consent to obtain the child's vaccination history from their health-care provider. Data were obtained on hepatitis B vaccine, MMR, Td, and varicella vaccine.

Of 741 households contacted with an eligible child, 489 (66.0%) participated in the survey. Vaccination histories were verified for 203 (41.5%) participants; verification methods included parent-held records (n=84), provider records (n=75), and parent-held and provider records (n=44). Among the remaining 286 (58.5%), reasons no parent-held record or provider record was available included 1) a written record could not be located by the parent; 2) consent to contact the provider was not given; 3) provider could not be contacted; 4) medical record could not be located; or 5) medical record lacked vaccination data.

Among the 203 children with verified vaccination records, 15.8% had received three doses of hepatitis B vaccine, and 26.6% had received one or two doses; 70.0% had received two doses of MMR, 16.2% of those reporting no history of chicken pox had received varicella vaccine, and 9.4% had received a Td booster (Table 1). Vaccination coverage for fifth graders was similar to that for sixth graders.

Among the 286 children whose vaccination information was not verified by parent-held or provider vaccination records, 44.1% of parents (95% confidence interval [Cl]=38.2%-50.0%) reported that their child had received three doses of hepatitis B vaccine and 5.6% (95% Cl=3.2%-8.9%) reported that the child had received one or two doses. Forthese participants, reported coverage for children for two doses of MMR was 82.5% (95% Cl=77.3%-87.0%) and coverage for Td was 80.5% (95% Cl=75.0%-85.2%). Varicella vaccine coverage among 61 susceptible persons was 31.1% (95% CI=19.9%-44.5%).

Reported by: SW Klish, MPH, W Wang, MPH, L Linton, MPH, S Ross, N Fink, MSW, San Diego County Dept of Public Health, San Diego; C Edwards, MPH, Pre-Teen Health Project, San Diego; KM Peddecord, DrPH, Graduate School of Public Health, San Diego State Univ, San Diego; N Smith, MD, Immunization Br, California Dept of Health Svcs. A Deladisma, MPH, Association of Schools of Public Health, Atlanta, Georgia. Health Svcs Research and Evaluation Br, Immunization Svcs Div, National Immunization Program, CDC.

Editorial Note: This is the first study that has assessed population-based vaccination coverage of adolescents. The findings suggest that in the absence of a school requirement, most adolescents lack documentation of recommended vaccinations. Reliable estimates of vaccination coverage among adolescents are difficult to obtain. For example, reported coverage among children with record-verified vaccinations may underestimate actual coverage; if children do not visit the same health-care provider from birth through adolescence, parent-held records and providers' records may be incomplete. Frequently, parental recall of childhood vaccinations is inaccurate when compared with provider records [2]; however, no studies have assessed the validity of parental recall of adolescent vaccinations. New methods to accurately measure adolescent vaccination coverage are needed so that coverage levels can be assessed reliably, the impact of vaccination programs for adolescents measured, and overvaccination of adolescents resul ting from incomplete documentation avoided.

School vaccination requirements are an effective means of increasing vaccination coverage and preventing disease among children and adolescents [3,4]. Emphasis has been placed on hepatitis B vaccination requirements because of the substantial disease burden of hepatitis B among adolescents and young adults. Hepatitis B vaccination requirements for middle school entry have been implemented in 14 states and the District of Columbia [5]. In California, 477,584 seventh graders were subject to the 1999 seventh grade vaccination requirement of receipt of three doses of hepatitis B vaccine. An estimated 20,059 hepatitis B virus (HBV) infections and 168 HBV-related chronic liver disease deaths expected during the lifetime of this cohort may be averted if each seventh grader received the required three doses of hepatitis B vaccine [6].