General Principles of Epidemiology

Samantha M. Tweeten, PhD, MPH Epidemiologist

Epidemiology and Immunization Services Branch
Health and Human Services Agency
County of San Diego
San Diego, CA

April 11, 2024
Declarations of Conflicts of Interest:
  • Declaration of Conflicts of Interest: Samantha M. Tweeten has no potential conflicts of interest to declare.


Epidemiology—the study of the frequency, distribution, cause, and control of disease in populations—forms the basis of all health-related studies. It provides the background for interventions to reduce transmission of infectious organisms, reduce the number of healthcare-associated infections, and protect healthcare personnel from infection. Understanding the relationships of host, environment, and organism will aid the infection preventionist in designing studies to determine the causes of healthcare-associated infections and design and evaluate interventions.