Year of Publication



Public Health

Date Available


Degree Name

Master of Public Health (M.P.H.)

Committee Chair

Christina Studts, PhD

Committee Member

Robin Vanderpool, DrPH, CHES

Committee Member

Mark Swanson, PhD


Purpose: According to CDC statistics, prior to pertussis vaccine development in the 1940’s, about 200,000 children contracted pertussis annually. Today, although this number has decreased drastically, pertussis cases began trending upward again in the 1980’s. There are several proposed contributory factors, including vaccination exemption. In Kentucky, there are both medical and religious exemptions to mandatory school vaccines. The purpose of this study was to examine possible correlations between reported school vaccination exemptions and pertussis incidence in Kentucky counties between the years 2004-2012.

Methods: This study retrospectively analyzed data from 120 Kentucky counties between 2004-2012. The Commonwealth of Kentucky School Annual Immunization Survey was used to collect data on vaccination exemptions in both kindergarten and sixth grade students. Statewide Communicable Disease Case Reports and 2010 Census county populations were used to calculate annual pertussis incidence rates. The correlation between overall annual exemption rates and pertussis incidence for Kentucky was tested using a Spearman Rank Order Correlation. Friedman tests were conducted to test for change over time with both vaccination exemption rates and pertussis incidence. Counties were grouped into two categories via a median split. A Mann-Whitney U test was then used to assess the difference in pertussis incidences between these two groups. As a secondary analysis, Mann-Whitney U was also used to assess the difference in pertussis incidence and religious exemptions between Appalachian and non-Appalachian counties. The study received IRB exemption from both the University of Kentucky and Kentucky Cabinet for Health and Family Services (CHFS) Institutional Review Boards.

Results and Conclusions: It was found that there was a positive correlation between increasing exemption rates and increasing pertussis incidence for the overall data set (rho=0.176, p

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