1.1. Defining Public Health

Objectives:

• Define public health and surveillance.
• Identify the key goals of public health.
• List the three different tiers of public health.

What is Public Health?

To kick off our journey in learning about Public Health, we need to start with a few basics. Let’s define what public health is.

Public health focuses on keeping communities healthy by preventing infection and promoting health, by increasing life expectancy (average number of years a person is expected to live) and by promoting wellbeing through collective efforts.

It prioritises improving the health of an entire population by addressing three aspects that affect health. These are social factors, environmental factors, and economic factors.

Social factors can be something such as the stigma of contracting certain diseases like Tuberculosis. An example of an environmental factor is contaminated water that can lead to outbreaks such as Cholera, while an economic factor could be the challenge that communities with high poverty may not have the necessary infrastructure (facilities like water, power, transport and finances) to get help in a timely manner.

It is important to understand how these three factors interact with biological data (data generated from analysing samples collected from organisms, e.g. blood) to contribute towards more effective public health strategies.

Key Goals for Public Health

Some of the key goals of public health are to improve health equity – which means that all individuals, regardless of socioeconomic status (social standing based on income, education, and job), have access to quality care and health opportunities.

It also aims to improve existing policies (official guidance plans) by using biological data to inform new intervention strategies. This means that instead of relying on guesswork, intuition and theories, policies are based on facts and evidence from data analysis (studying biological data to find patterns).

Lastly, public health aims to improve health system management (coordinating resources to provide effective healthcare) by addressing broader factors such as nutrition, education, sanitation, and access to medical services (clinics, hospitals, other healthcare facilities and associated workforce).

Question

Why do you think people choose a career in Public Health?

Defining Surveillance

In public health, surveillance means regularly collecting, analysing and sharing biological data so we can keep track of what’s happening in a community. It helps us spot patterns, pick up early signs of outbreaks (defined in module 2.1), understand health trends and make informed decisions about the interventions (planned actions to improve health or prevent disease) and policies needed to protect communities.

This involves continuously keeping an eye on health information to spot potential public health threats early. We can look at how often people are infected by certain pathogens (virus, bacteria or fungi that cause disease) over time (disease incidence), what risk factors are present and what’s happening in the environment, such as different weather patterns. By analysing this data, we can identify trends that help us better understand health problems and what’s driving them. That understanding then leads to practical insights that support public health strategies and interventions.

The ultimate goal of surveillance is to use this information to implement measures that reduce health risks and protect communities, making it an essential tool for early warning, tracking disease trends and safeguarding public health.

Levels of Public Health Operations

We already know that public health is different to general healthcare, because it doesn’t just take the health of an individual into account. But even public health can be organised into different categories.

Local public health focuses on improving health at the community level by using surveillance and interventions that might target specific diseases or health challenges that are prevalent (common or widespread in a specific place or group). An example of local public health is a vaccine outreach programme at a church or school.

When health systems work together to address large-scale issues that affect many communities – whether it’s managing chronic diseases (long-lasting condition progressing over time) or preparing for a rise in disease cases – we refer to it as national or regional public health. An example of organisations which operate at this level, are your national public health labs. They may receive blood or sputum (mucus from the lungs used for medical testing) samples from clinics across the country to report whether patients have tested positive or negative for a particular disease.

Many health challenges can’t be solved by one country alone. They often cross borders – like infectious diseases that spread internationally or persistent health inequities. So, they require coordinated global efforts to address them. This is an example of global public health. Organisations which focus on health globally are often multi-faceted, with several establishments worldwide, such as the World Health Organization (WHO).