Middle School Vaccination Requirements and Adolescent Vaccination Coverage

Discussion

To our knowledge, this is the first study to evaluate the association of middle school vaccination and education requirements with vaccination coverage for the most recently recommended vaccines for adolescents (TdaP, MenACWY, and HPV). Results from our analysis indicate that requirements for adolescent vaccination for school entry were associated with higher coverage for Td/TdaP and MenACWY vaccines and no association was found between educational requirements and coverage levels for MenACWY or HPV vaccines.

Among the vaccines studied, requirements for a tetanus booster were more frequent and had been in place the longest given that Td had been recommended for adolescents before the licensure of TdaP. Vaccination coverage with ≥1 doses of Td/TdaP was 10 percentage points higher among states that had a Td/TdaP requirement in comparison with states with no requirement. Vaccine specificity was also found to be important as coverage with TdaP was 8 percentage points higher among states with a TdaP-specific requirement in comparison with states that did not specify TdaP in their requirement. The importance of vaccine specificity in the tetanus booster requirement may lessen over time given several factors. When TdaP was first licensed, the ACIP recommended that persons who previously received Td wait 2 to 5 years before receiving TdaP; thus, some adolescents included in the 2009 NIS-Teen who had received Td may not have been eligible to receive TdaP. Recently, the ACIP removed the 2- to 5-year interval and now recommends that providers do not wait to administer TdaP.²¹ Because the majority of adolescents who received a tetanus booster since 2006 have received TdaP,²² even if a requirement is not vaccine-specific, it is expected that most adolescents will receive TdaP for their booster. TdaP-specific requirements were represented in both new requirements for the 2008–2009 school year and preexisting tetanus requirements, which may explain why we observed similar increases in TdaP coverage from 2008 to 2009 for new Td/TdaP requirements in comparison with preexisting requirements.

States with a MenACWY requirement had coverage 17 percentage points higher than states without a MenACWY requirement. Caution should be used when interpreting these results, because only 3 states had a requirement. However, all 3 states implemented their requirement during the 2008–2009 school year and, on average, achieved 70% coverage with MenACWY 1 year after implementation, well over the national average.

Preventive health care visits, when vaccines are most likely to be administered, occur less frequently among adolescents.²³ Providers are encouraged to take advantage of every encounter to assess an adolescent’s vaccination status and administer needed vaccines.²⁴ When an adolescent visits a provider to obtain the vaccine(s) required for school entry, this would be an ideal opportunity to administer other recommended (though not required) vaccines. Unfortunately, our study found that the presence of 1 or more vaccine requirements for school entry was not associated with higher overall vaccination coverage in comparison with states with no requirements. The low overall coverage observed among adolescent girls is driven by low HPV coverage. Studies have shown that providers are less likely to recommend this vaccine to younger adolescents, and parental acceptance of the vaccine is variable.^25–27 Thus, there may be greater issues that need to be addressed to increase HPV vaccination coverage beyond creating a vaccination opportunity.

School vaccination requirements are recommended as an evidence-based strategy by the Task Force on Community Preventive Services to improve vaccination coverage levels.^28,29 Although vaccination requirements may be an important public health policy, they may not be feasible for every vaccine or in every location. Several organizations, including the National Vaccine Advisory Committee,¹⁵ the Association of Immunization Managers,³⁰ and the State of Washington³¹ have come forward with position statements outlining the factors that states should consider when pursuing a vaccine requirement for school entry, including (1) partnership with state and local personnel and providers; (2) infrastructure issues such as vaccine purchasing, supply, and storage; (3) consistency with existing school entry requirements; and (4) adequate political and public support.¹⁵

Lacking the necessary political, public, or financial support to implement a vaccine requirement, some states may pursue education requirements. Several studies have shown that parental awareness of the vaccines recommended for adolescents is low,^32–34 lending support to these types of requirements. Most educational requirements require dissemination of educational materials to parents through the school system, which can take many forms; materials may be mailed directly to parents, sent home with children, or included on forms for reporting receipt of required vaccinations. Educational materials may or may not require documentation that parents have received them, such as a parental signature. Results from our study indicate that unlike vaccine requirements, educational requirements are not associated with higher coverage. Overall vaccination coverage for educational-only requirement states was significantly lower than states with no requirements; however, statistical differences were not observed for MenACWY and HPV coverage, respectively. Although the NIS-Teen prevents us from assessing causality, we do not think the educational materials themselves caused lower overall coverage levels, and perhaps other sociodemographic factors not controlled for may be contributing to the finding. The more likely scenario behind the individual vaccine results is that the educational materials are not reaching the target audience. A 2010 study found that despite North Carolina’s education requirement for HPV vaccine, only 9% of mothers surveyed in the state had heard about the vaccine via their daughters’ schools.³⁵ Further evaluation of education requirements including distribution methods, message content, and influence on parental attitudes toward vaccines is needed to ensure that states are utilizing resources effectively.

Level of enforcement of school entry requirements varies among states and even within states.^36,37 A 2004 study suggests that knowledge and attitudes of school nurses and individuals charged with enforcing requirements may have an important impact on level of enforcement and number of exemptions granted.³⁶ Although school entry requirements do appear to lead to increased vaccination coverage levels, such an increase is not guaranteed without adequate enforcement of requirements.

This study is not without limitations. The NIS-Teen is a random-digit–dialed survey limited to landline households; it may not be representative of nonlandline and wireless-only households, which could contribute to noncoverage bias. The exclusive use of provider-verified vaccination histories may lead to underestimates of vaccination coverage, because the completeness of these records is unknown. This analysis does not account for any activities states may have implemented promoting adolescent immunization or differences in state policies such as vaccine financing. The potential influence of any differences in sociodemographic factors across states was also not taken into account. The vaccine and education requirements that were reviewed generally apply to adolescents ages 11 to 13. The NIS-Teen includes adolescents 13 to 17 years of age; therefore, depending on when the requirement was implemented, most of the teens included in the NIS-Teen may not have been directly affected by the requirements. However, we observed higher coverage levels in states with requirements for TdaP and MenACWY, which may suggest an indirect benefit to older teens. The NIS-Teen began collecting state-level vaccination data in 2008; therefore, we were unable to evaluate change in vaccination coverage pre- and postimplementation among states that implemented a requirement before the 2008–2009 school year. The number of states with requirements for MenACWY and HPV vaccines in 2008–2009 was small, so caution should be used when interpreting results for these vaccines. Many of the requirements for MenACWY and HPV were only in place for 1 year at the time of our analysis; additional time may be needed before full implementation of the requirements has been achieved.

Adolescent vaccination coverage levels are increasing but remain low. Less than half of adolescent girls 13 to 17 years of age have initiated the HPV series. A statistical model predicting HPV vaccine uptake over a 50-year time horizon shows that, in the absence of school requirements, it will take 23 years to achieve 70% coverage for the complete series.³⁸ The likelihood of widespread HPV vaccine requirements for school entry appears to be low. Since the HPV vaccine was licensed in 2006, 24 states have proposed legislation regarding middle school entry requirements for HPV vaccine for adolescent girls. To date, only 2 of these proposals have resulted in vaccination requirements (District of Columbia and Virginia).¹⁸ Reasons for this low rate of success for proposals include the high cost of the 3-dose vaccine series, sexual transmission of the virus, and lack of public support for a requirement.³⁹ In the absence of school requirements for HPV vaccine, identifying effective strategies to increase initiation and completion of the HPV vaccine series will be necessary.

Since the 2008–2009 school year, 21 states have enacted new or updated vaccination requirements for TdaP, 6 new requirements for MenACWY, and 1 new requirement for HPV vaccine. Of the new TdaP requirements, 14 replaced older Td requirements and 7 are states with no previous Td requirement.^5,18,40 We will continue to monitor the impact these requirements have on coverage.