Levels of Prevention: Our Lines of Defense


Samantha, Jim, and Nina are in algebra class together. Recently, their teacher taught them about factoring. Nina decided to stay after class that day to ask the teacher questions about the lecture so she could better understand the material. Jim went home after class and did the homework. He got confused, so the next day he asked the teacher for help. Samantha didn’t pay much attention to the homework or ask questions until the day before the test. When the teacher gave back their tests, Nina received an A, Jim got a B, and Samantha got a D.


Nina and Jim’s early attempts to learn the material helped them perform better on the test. Similarly, early attempts to prevent disease drastically improve health outcomes. In fact, public health experts identify three types of prevention that correspond to different stages of disease.

Three Levels of Prevention

There are three levels of disease prevention in public health. Primary prevention aims to stop behaviors that cause disease through education, legislation, and vaccinations on a population level. Secondary prevention involves individual screening to catch a disease as early as possible. Tertiary prevention involves a doctor and patient making a care plan to slow or stop the progression of the disease.

How It Works

The easiest way to improve health outcomes is to prevent the disease entirely through primary prevention. This type of prevention usually includes education, laws banning certain substances such as hard drugs, or more medical methods such as vaccination. It occurs on a larger scale within communities, states, nations, and the world through public health campaigns. For example, to prevent diabetes, a public health worker might come into a school and give a presentation on healthy eating habits. When done correctly, primary prevention targets behaviors that cause disease, thus preventing the disease and improving health outcomes.

The next best thing to preventing disease is catching the disease early through secondary prevention, before it has time to cause negative health outcomes. For example, if a person was at risk for diabetes, their doctor will routinely check their blood sugar and A1C. If the doctor noticed abnormalities, they would likely work with the patient to lower their blood sugar to prevent diabetes that affects the rest of the body. 

When both of these measures fail to prevent disease, it is important to stop the disease from damaging parts of the body through tertiary prevention. A doctor will work with their patient to make sure the disease is managed as best as possible. For example, if someone is diagnosed with type 2 diabetes, their doctor will often recommend diet changes to prevent the diabetes from getting worse.

Why Care?

While all levels of prevention are critical tools in improving the health of populations, primary prevention is the best way to stop disease. Because these methods are often controlled by public health officials, primary prevention relies on government funding.

The problem is that most public health departments are chronically underfunded. Since 1960, the U.S. federal government has cut the proportion of public health funding by 30%. Across the nation, researchers estimate public health departments are 4.5 billion dollars short of what they need. Because of this lack of funding, our healthcare system primarily focuses on tertiary prevention, after the disease has caused negative health effects. 

It is important that all levels of our government increase funding for public health departments to prevent negative health outcomes. Contact your representatives, local state and federal, and urge them to increase funding for preventative public health measures. 

Think Further

  1. Do you think that more primary prevention education should take place in school curriculum? Why or why not?
  2. What are some ways that our society can focus more on preventing disease?
  3. Do you think medical research should focus more on primary prevention or tertiary prevention? Why?


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Learn More

  1. “Picture of America: Prevention.” United States Center for Disease Control, 2013, www.cdc.gov/pictureofamerica/pdfs/picture_of_america_prevention.pdf. 
  2. Haseltine, William A. “Underfunding Public Health Harms Americans Beyond Covid-19.” Forbes, Forbes Magazine, 21 Oct. 2020, www.forbes.com/sites/williamhaseltine/2020/10/21/underfunding-public-health-harms-americans-beyond-covid-19/?sh=11ac08c8419c. 
  3. “EPHO5: Disease Prevention, Including Early Detection of Illness.” World Health Organization, World Health Organization, www.euro.who.int/en/health-topics/Health-systems/public-health-services/policy/the-10-essential-public-health-operations/epho5-disease-prevention,-including-early-detection-of-illness2.