What is Public Health?

Public Health is defined as “the art and science of preventing disease, prolonging life and promoting health through the organized efforts of society” (Acheson, 1988; WHO).

Public Health focuses on the entire spectrum of health and wellbeing, not only the prevention of specific diseases. Public Health practice is essential to all aspects of health and wellbeing and plays a crucial role in modifying the wider determinants of health for reducing health inequalities. Public Health’s historic endeavours have led to enormous advances in the control and eradication of numerous deadly infectious diseases, reduction of nutritional deficiencies, provision of clean water and great advances in sanitation, and prolongation of life and improvement of health and wellbeing through the reduction of the burden of chronic diseases at the population level.

The overall vision is to promote greater health and well-being in a sustainable way, while strengthening integrated public health services and reducing inequalities. To achieve this vision, Public Health practitioners work in collaboration with other sectors in a multidisciplinary approach.

Public Health is, by default, multidisciplinary and requires the “organised efforts of society” Some necessary ingredients of successful Public Health action are:

  • a “whole-of-government” and “whole-of-society” approach, to achieve cross-sectoral synergies, guided by shared values and common goals
  • dedication to the principles of “Health for all” (i.e. recognizing the persisting inequalities in health) and “Health IN all and FOR all Policies” (i.e. recognizing the close interconnection of Health with broader policies and the means though other goals can be achieved)
  • strong links between epidemiological and other research with the policy-making process in the context of designing, planning, implementing and evaluating evidence-based Public Health policy and practice, and
  • a meaningful exchange with the community through the adoption of Public Participation, Involvement and Engagement approaches.

Public Health achieves this monumental task, mainly through focusing on the following 5 domains

Health Protection is one of the core domains of Public Health work. It is defined as the protection of individuals, groups and populations through expert advice and effective collaboration to prevent and mitigate the impact of infectious diseases, as well as environmental, chemical, and radiological threats. Specific Public Health services under this domain include infectious disease prevention and control, occupational health assessment, food safety assessment, and protection of environmental threats, such as natural disasters and radiation. The following years, with the climate crisis becoming more and more prominent and new epidemics arising, health protection is anticipated to have an increasingly important role.

Health Promotion is another core domain of Public Health, which goes beyond protection, aiming for the constant improvement of health and wellbeing in communities, nations and globally. This aim is primarily achieved either through educating and empowering individuals to lead a healthier life, or through addressing underlying determinants of health, such as poverty, lack of educational opportunities, poor infrastructure and and general deprivation. Health promotion plays a vital role in reducing the burden from chronic non-communicable diseases. The following years, due to the major issue of population ageing, particularly in high income countries, chronic diseases are anticipated to have a huge impact on global health, thus health promotion will be vital for their management.

Disease prevention is a key focus and activity of Public Health. It refers to organised efforts and specific interventions by public health authorities and actors aimed at reducing the onset, burden and/or severity of disease and/or exposure to risk factors. Prevention can apply at the level of the individual and/or community and population-wide. Efforts may target high-risk individuals (e.g. medication for hypertension) or whole populations (e.g. car seat belt, smoking bans, taxes on sugary beverages). Prevention operates at different levels:  

  • Primordial: aimed at preventing the emergence of risk factors by addressing broader social, economic, cultural and environmental determinants of health, such as sanitation and work safety measures, improving living conditions, tackling socio-economic disadvantage and reducing inequalities, including but not restricted to equitable access to healthcare services
  • Primary: aimed at preventing the onset of disease or injury and/or reducing or eliminating exposure to risk factors, such as immunization against infectious diseases, nutritional and food supplementation, smoking bans or control of hazardous substances.  
  • Secondary: aimed at timely detection of signs and symptoms of disease in order to halt or slow the progression, introduce early intervention and improve outcomes, such as cancer screening, or school- and community- screening programmes, and
  • Tertiary: aimed at reducing the burden, severity and consequences of disease once it occurs, in order to improve quality of life, prevent disability and/or reduce mortality, such as chronic disease management and rehabilitation programmes.

Public Health services overlap with the above two domains and could aim to protect (e.g., vaccination programmes) or improve (e.g., health promotion campaigns) population health. Public health services can also include, generation and communication of vital statistics, health education, maternal and child care, food and water sanitization, and screening for secondary prevention. Additionally, Public Health may provide services related to overcoming obstacles in access to healthcare and ensuring equal health coverage for all, thus addressing health inequalities. Unfortunately, this domain is usually overlooked in the majority of countries around the world, where usually it is assumed that by providing universal health coverage, people have uninterrupted and equal access to healthcare.

Health inequalities are systematic differences in the health status of different population groups, usually driven by socioeconomic inequalities and unequal opportunities to education and resources, rooted in the structure of modern societies. Health inequalities are thus arising from the social conditions in which people are born, grow, live, work, and age. These wider determinants of health are the main target for efforts in reducing health inequalities, which have significant social and economic costs, both to individuals and societies. Fortunately, the last 20 years have seen the global problem of health inequalities receiving the appropriate attention, at least in most of the developed world, and has thus been included as a separate domain of Public Health practice.