In the world of health care- the clinician works with patients individually. They examine various indicators of health for their patient including direct observations and laboratory or other diagnostic tests and implement interventions to help their patient improve their health. Providers also encourage their patients to live healthy lifestyles and take safety precautions- and help patients with preventative care by providing vaccinations and the like. Over time, the health care provider follows the patient and measures how they’re doing with patient centered criteria.
In the world of public health, the practitioner works with communities… in other words the community is the patient. Public health folks look at outcome indicators to determine the health of the community so they can take action and implement interventions at the wholesale level to improve population health. In other words- public health uses community indicators like infant mortality, communicable disease rates, obesity and diabetes to assess the patient (the community). Of course, public health relies on health care providers in the health care world to carry out public health objectives and interventions.
So you can see that there is a strong interface between health care and public health- but the distinction is that in health care the patient is the patient while in public health the community is the patient- the interventions are community based, and community indicators are the primary assessment tool. By the way, reports suggest that behavior accounts for roughly 50% of health outcomes, genetics about 20%, the environmental about 20%, with medical care about 10%… 96% of our national health expenditures are focused on medical care with about 4% dedicated to prevention. Does prevention sound like a good investment?