Year of Publication



Public Health

Date Available


Degree Name

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

Committee Chair

Dr. Jay Christian

Committee Member

Dr. Kathleen Winter

Committee Member

Dr. Erin Haynes


Objective: Provide epidemiologic overview of SARS-CoV-2 breakthrough infections in Kentucky considering both demographic and geographic variables.

Background: We believe descriptive information of breakthrough cases for a defined population will provide public health practitioners with useful information relating to SARS-CoV-2 infection control and vaccination efforts.

Methods: We obtained SARS-CoV-2 case data from the Kentucky Department for Public Health COVID-19 case repository, which mirrors National Electronic Disease Surveillance System (NEDSS) data. The study sample used for analysis comprised 147,000 individuals who tested positive for SARS-CoV-2 in Kentucky between the dates of March 1st, 2021 and December 31st, 2022. Breakthrough cases were defined as SARS-CoV-2 infections for those who had completed their primary vaccination series or those who have completed a primary vaccination series and one or more booster dose.

Results: Breakthrough cases were more often female, in an older age category, non-Appalachian residents, and lived in ZIP codes where residents have higher estimated socioeconomic status on average. The results of the bivariate analysis were robust after being adjusted for all other variables in the multivariate analysis, and the dose response relationship seen with age category and ZIP code estimated household income and educational attainment held consistent.

Conclusions: Breakthrough cases’ characteristics are like characteristics of individuals who are more likely to be vaccinated. Breakthrough infections were more common in areas with high vaccine adherence as well as in areas with high community transmission.

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