Individual clinical care cannot protect whole populations alone. Public health is the science and practice of protecting and improving the health of communities through education, policy, surveillance, and organized interventions.

Core functions include monitoring health status, investigating outbreaks, informing the public, mobilizing partnerships, developing policies, enforcing laws, linking people to care, assuring a competent workforce, evaluating services, and research. Vaccination programs, clean water, tobacco control, and road-safety measures exemplify successful public-health action.

Public health balances individual liberties with collective benefit and must address inequities that drive unequal outcomes. Data and communication are its primary tools. When public health succeeds, the diseases and injuries that do not occur are its quiet triumphs.

• Science of protecting and improving community health
• Uses surveillance, policy, education, and prevention programs
• Addresses infectious, chronic, and injury-related threats
• Focuses on populations and health equity