Public health is a discipline that studies the ways people’s environment, behavior and culture influence their physical well-being. It includes the study of diseases, injuries and their prevention as well as the study of how a person’s lifestyle affects his or her disease risk. Public health interventions range from vaccination to community outreach to smoking cessation programs. In the United States, the federal government plays a major role in public health through its responsibilities and funding for state-level agencies, such as local or county departments of public health, infectious disease laboratories and cancer screenings.
Historically, many of the first public health initiatives were designed to control communicable diseases like cholera or typhoid fever. These included the construction of sewer systems and draining swamps to prevent mosquito breeding, as well as educational campaigns encouraging people to wash their hands or cover their mouths when coughing or sneezing. Later, the germ theory of disease helped lead to the development of a more systematic approach to disease control, such as the formation of public health boards and infectious disease labs in many cities and towns.
At the national level, Congress sets policy and oversight for many public health issues. Federal funding varies between states, and is sometimes supplemented by local or city sources. Local governance models also vary, with regional, county and city health departments often having more autonomy than state-level programs. This can make coordination challenging during national emergencies, such as COVID-19.