School Immunization Data Helps Identify Areas at Risk for Outbreaks

State and local vaccination requirements for school entry are implemented to maintain high vaccination coverage and protect schoolchildren from vaccine-preventable diseases. Each year, to assess state and national vaccination coverage and exemption levels among kindergartners, the CDC analyzes school vaccination data collected by federally funded state, local, and territorial immunization programs. This report describes vaccination coverage in 49 states and the District of Columbia (DC) and vaccination exemption rates in 46 states and DC for children enrolled in kindergarten during the 2013–2014 school year. Although state vaccination coverage is high and exemptions are low, under-vaccination and exemptions cluster at a local level, where vaccine-preventable diseases might be easily transmitted.


Health departments, school nurses, or school personnel assess the vaccination and exemption status, as defined by state and local school requirements, of a census or sample of kindergartners enrolled in public and private schools. Among the 49 states and DC reporting vaccination coverage data, 42 used their immunization information system (IIS) as at least one source of data for their school assessment.


Most federally funded immunization programs continued to report high vaccination coverage and stable exemption rates among kindergartners during the 2013–2014 school year compared with the 2012–2013 school year, although 26 states and DC did not report meeting the Healthy People 2020 target of 95% coverage for two doses of MMR vaccine. In 49 states and the District of Columbia (DC), median vaccination coverage for three vaccines was 94.7% for the measles, mumps, and rubella vaccine, 95.0% for varying local requirements for the diphtheria, tetanus toxoid, and acellular pertussis vaccine, and 93.3% for varicella vaccine among states with a two-dose requirement. Median exemption levels continue to be low overall (1.8%).


Although high levels of vaccination coverage by state are reassuring, vaccination exemptions have been shown to cluster geographically, so vaccine-preventable disease outbreaks can still occur where unvaccinated persons cluster in schools and communities. Immunization programs might have access to school vaccination coverage and exemption rates at a local level for counties, school districts, or schools that can identify areas where children are more vulnerable to vaccine-preventable diseases. Health promotion efforts in these local areas can be used to help parents understand the risks for vaccine-preventable diseases and the protection that vaccinations provide to their children.


Vaccination requirements for school entry, as reported to the CDC by the federally funded immunization programs, varied. Kindergartners were considered up-to-date for any single vaccine if they have received all of the doses of that vaccine required for school entry in their jurisdiction. Nine states considered kindergartners up-to-date only if they had received all of the doses for all vaccines required for school entry in their jurisdiction. Of the 49 states and DC reporting vaccination coverage, 13 met CDC standards for school assessment methods in 2013–2014.


School vaccination coverage assessment is used to assess state or local-level school vaccination requirements. Eighteen states provide local-level data online, helping to strengthen immunization programs, guide vaccination policies, and inform the public. Local-level school vaccination and exemption data can be used by health departments and schools to focus vaccine-specific interventions and health communication efforts in a school or local area with documented low vaccination coverage or high exemption rates. Where expanded health communication strategies or other interventions are implemented, continued assessment and reporting can be used to facilitate program improvement.


To be most effective, accurate and reliable estimates of vaccination coverage and exemptions are needed. Use of appropriate sampling and survey methods can improve the usefulness of data for local use and comparability of estimates across school, local area, state, and national levels to accurately assess vaccination coverage and track progress toward Healthy People 2020 targets.


School vaccination coverage reporting can be labor intensive, involving education systems at the start of the school year, when the schools are busiest. School vaccination assessment systems can be linked to an IIS, allowing schools to review the vaccination status of individual children. During the 2013–2014 school year, 36 of the 50 states and DC reported that they allowed schools to obtain provider-reported vaccination data from their IIS, and 14 reported using an Immunization Information System (IIS) algorithm to determine vaccination status for at least some of the students in their school vaccination assessment.


An example of how an Immunization Information System (IIS) can be used to simplify school vaccination assessment is Tennessee's Immunization Certificate Validation Tool, which compares a child's record in the state IIS against Tennessee vaccination requirements for pre-school or school attendance, allowing vaccination providers and school nurses to quickly assess a schoolchild's vaccination status. It produces an official Tennessee Immunization Certificate or a detailed failure report. Tools linking school vaccination assessment systems to IIS data provide access to provider-reported information, reduce the documentation burden on parents and vaccination providers, and lessen the workload required by the assessment process on schools and health departments.


State and local school vaccination assessments might detect local areas of under-vaccination where disease transmission is more likely to occur. These data are most useful when the assessment is accurate and reliable. Use of statistically appropriate sampling methods and access to provider-reported vaccination data in an IIS can streamline the data collection process while providing accurate local-level data, allowing health departments to appropriately direct vaccination efforts during outbreaks of vaccine-preventable disease and identify schools and communities potentially at higher risk for vaccine-preventable disease transmission. Accurate local-level data can also be used by health departments and schools to focus health communication and other interventions that protect children and the community at large against vaccine-preventable diseases.


Local data are essential to controlling the spread of vaccine-preventable disease. Accurate and reliable school vaccination assessments can provide a unique opportunity for school and health departments to identify local areas of under-vaccination, even at a school or classroom level, where the potential for disease transmission is higher. Health departments can use the data to identify schools and communities at higher risk for outbreaks and provide health communication interventions to protect school children and the community at large against vaccine-preventable diseases.


See the CDC Report


See also Medical Law Perspectives, January 2013 Report: Vaccines: An Ounce of Prevention May Lead to a Pound of Injury