Community Health Worker (CHW) Practice Exam

Epidemiology focuses on how diseases are distributed in populations and what determines their occurrence. It uses data to spot patterns, compare rates, and judge how well public health actions work. Comparing disease rates between populations is fundamental because it reveals differences in incidence, prevalence, or mortality that prompt investigation and action. Identifying patterns of illness—such as who is affected, where, and when—helps uncover risk factors and transmission dynamics. Evaluating the effectiveness of public health programs uses epidemiologic methods to see whether interventions actually reduce disease burden or improve outcomes. Creating vaccines, while crucial to disease control, belongs to biomedical science and immunology. Epidemiology may study vaccine effectiveness after deployment, but the development and creation of vaccines themselves are outside its typical scope.