Given how it seems our United States population is extremely divided in matters of science and scientific progress, and without picking on these opposites with useless arguments, I will offer a short explanation of what is meant by Public Health (the science and practice of preventing disease, promoting health, and improving community well-being through policies, education, and interventions).
Two of the most important achievements in human history are vaccines and handwashing. By the 20th century, handwashing became a key part of medical practice, especially after scientists discovered that bacteria and viruses cause infections1. In the 1980s and 1990s, the CDC created hand hygiene guidelines, making it clear that washing hands was essential in preventing infections in healthcare settings2.
A vaccine is a shot or medicine that helps the body learn how to fight off a disease by exposing it to a weak or harmless version of the virus or bacteria, so you don’t get sick later3. In 1796, Edward Jenner noticed that people who got cowpox didn’t get smallpox, so he used cowpox to protect people from smallpox4. Later, Louis Pasteur developed vaccines for rabies and cholera by weakening germs so they couldn’t cause illness5.
Over time, scientists improved vaccines by using parts of germs, called antigens, to train the body’s immune system. Newer methods, like genetic engineering and mRNA technology, have made vaccines faster to develop and more effective6. In the U.S., the push for widespread vaccination became a priority in 1986 when the government passed a law to make vaccines safer and more available for kids7.
Before that, the biggest vaccine effort was in the 1950s when Jonas Salk created the first polio vaccine8. In 1962, another law helped fund vaccine programs, leading to nationwide efforts to protect people from measles, mumps, and rubella in the 1960s and 70s9. The most recent large-scale vaccination effort was during the COVID-19 pandemic in 202110.
By 2025, there are over a dozen critical vaccines that protect people from serious diseases at different stages of life. Kids and teens get vaccinated for diseases like hepatitis A and B, rotavirus, diphtheria, tetanus, whooping cough, pneumonia, polio, flu, measles, mumps, rubella, chickenpox, meningitis, and HPV, which can cause certain cancers11. Adults are recommended to get vaccines for shingles, pneumonia, and COVID-19, depending on their health and age12. These vaccines save lives and prevent dangerous outbreaks.
In the last 100 years, advances in medicine and public health have completely changed how people live. Vaccines for diseases like polio, measles, mumps, rubella, and hepatitis have saved millions of lives and even eliminated some diseases13. The discovery of antibiotics, like penicillin in 1928, made it possible to treat bacterial infections that were once deadly14. Public health efforts, like better sanitation, clean water, vaccination programs, and health education, have helped people live longer and healthier lives15.
Life expectancy in the United States improved a lot during the 20th century because of advancements in medicine, public health, and living conditions. In 1900, the average life expectancy was about 47 years. By 1950, it had jumped to around 68 years, and by 2000, it had reached nearly 77 years. By 2012, life expectancy was 78.8 years16.
Throughout history, women have lived longer than men. In 1900, men had a life expectancy of about 46 years, while women lived to around 48 years. By 1950, men could expect to live about 66 years, while women lived to about 71. In 2000, men had a life expectancy of 74 years compared to 80 years for women. By 2012, men lived to about 76 years, while women reached 81 years on average17. Women consistently live longer than men for several reasons, including biological differences, lifestyle choices, and social factors18.
Overall, the increase in life expectancy over time is due to better medical care, improved nutrition, public health measures, and better living conditions19. Surgery and anesthesia have improved, making complex procedures safer. Genetic research has led to better diagnosis and treatment of genetic disorders and cancer. HIV/AIDS treatments now allow people to live long, healthy lives. Awareness of mental health has increased, leading to better treatments and support. Advances in heart disease and stroke treatment, including bypass surgery, stents, pacemakers, and cholesterol-lowering drugs, have saved lives. Cancer treatments like chemotherapy, radiation, immunotherapy, and targeted drugs have improved survival rates. Reproductive health care has helped improve women’s health and lower infant mortality. All of these breakthroughs have transformed public health, extended life expectancy, and improved the quality of life for billions of people. Medicine is the examination of the individual, and Public Health looks at entire populations.
Footnotes:
1. Semmelweis, I. (1861). Die Ätiologie, der Begriff und die Prophylaxis des Kindbettfiebers. Vienna: C.A. Hartleben.
2. Centers for Disease Control and Prevention (CDC). (1985). Guideline for Handwashing and Hospital Environmental Control. Atlanta, GA: CDC.
3. Plotkin, S., Orenstein, W., & Offit, P. (2017). Vaccines (7th ed.). Philadelphia: Elsevier.
4. Jenner, E. (1798). An Inquiry into the Causes and Effects of the Variolae Vaccinae. London: Sampson Low.
5. Pasteur, L. (1885). Méthode pour prévenir la rage après morsure. Comptes Rendus de l’Académie des Sciences, 101, 765–772.
6. Weiss, R. & Pardi, N. (2020). mRNA Vaccines: A New Era in Vaccinology. Nature Reviews Drug Discovery, 19(4), 261–279.
7. National Childhood Vaccine Injury Act (1986). Public Law 99-660. U.S. Government Printing Office.
8. Salk, J. (1955). Studies in Human Subjects on Active Immunization Against Poliomyelitis. JAMA, 151(13), 1081–1098.
9. U.S. Public Health Service Act (1962). Public Law 87-838. Washington, DC: U.S. Government Printing Office.
10. Centers for Disease Control and Prevention (CDC). (2021). COVID-19 Vaccination Program Operational Guidance. Atlanta, GA: CDC.
11. World Health Organization (WHO). (2025). Expanded Programme on Immunization (EPI): Global Vaccine Recommendations. Geneva: WHO.
12. Advisory Committee on Immunization Practices (ACIP). (2024). Adult Immunization Schedule, United States. Atlanta, GA: CDC.
13. Roush, S. W., Murphy, T. V., & The Vaccine-Preventable Disease Table Working Group. (2007). Historical Comparisons of Morbidity and Mortality for Vaccine-Preventable Diseases in the United States. JAMA, 298(18), 2155–2163.
14. Fleming, A. (1929). On the Antibacterial Action of Cultures of a Penicillium. British Journal of Experimental Pathology, 10(3), 226–236.
15. Winslow, C. E. A. (1920). The Untilled Fields of Public Health. Science, 51(1306), 23–33.
16. Arias, E. (2014). United States Life Tables, 2010. National Vital Statistics Reports, 63(7), 1–63.
17. National Center for Health Statistics (2013). Health, United States, 2012: With Special Feature on Emergency Care. Washington, DC: U.S. Government Printing Office.
18. Austad, S. N. & Fischer, K. E. (2016). Sex Differences in Lifespan. Cell Metabolism, 23(6), 1022–1033.
19. Omran, A. R. (1971). The Epidemiologic Transition: A Theory of the Epidemiology of Population Change. The Milbank Memorial Fund Quarterly, 49(4), 509–538.
20. Deaton, A. (2013). The Great Escape: Health, Wealth, and the Origins of Inequality. Princeton, NJ: Princeton University Press.
