Epidemiology: contribution in the past, present, and future

I was on a flight from Rochester, NY to Chicago, IL when I encountered my first epidemiologist. I was sitting next to a guy who caught my attention because his first remark about being an epidemiologist was “There aren’t many of us”.  This was after we had a lengthy conversation about my future plans of being a medical doctor. I didn’t even know what epidemiologists really did except that they dealt with diseases and outbreaks, and that was the extent of my knowledge. It was only after I took an Epidemiology course during my junior year that I looked beyond the surface definition. This blog is dedicated to the wonders that epidemiology has contributed (3 points) and will continue to contribute (3 points) to the globe. Containing these wonders in only 6 points doesn’t do justice to the power of this field but it is a start.

Let us start with the past but undeniably remarkable achievements of Epidemiology/Epidemiologists:

  1. John Snow and investigation of cholera

This is probably my favorite epidemiology achievement because it shows how versatile the field is and how creative one has to be to link conditions and factors of health to a disease. Snow was able to trace the source of the cholera outbreak in London in the 1850s.  Cholera is an infectious disease that affects the small intestine leading to diarrhea which causes severe dehydration and death if left untreated. During Snow’s time, it was believed that Cholera was an “airborne” disease but Snow, like the boss he was, refused the idea and showed that Cholera was due to water contamination. When there was a Cholera outbreak in the Soho neighborhood of London, Snow was able to map the cases to all the streets and showed that the cases of cholera were centered on a well pump that was contaminated and the cases slowly disappeared when the authorities removed the well pump’s handle.


  1. Elimination of smallpox

Does the name Edward Jenner ring a bell? He is responsible for developing a vaccination for smallpox though his ways of doing it was….unorthodox i.e. he infected a HEALTHY 8-year-old boy with the cowpox (his theory was that people exposed to cowpox developed immunity to smallpox) THEN he infected this same 8-year-old boy with smallpox. The results you ask? He was right!

During the 1970s, cases of smallpox surpassed 10 million per year with more than 2 million deaths in more than 25 countries. By 1977, the last known case of smallpox was identified and smallpox was eradicated by 1980. How did epidemiology play a role? Though many other factors also played a role in the eradication of smallpox, Epidemiology used methods by using skills of creativity and innovation. After establishing that there were no non-human hosts, looking at the carriers as well as the inability of recovered patients to transmit (and thus also develop immunity) and other methods, they were able to establish the epidemiology of smallpox leading to its elimination.


  1. Smoking causes Lung cancer

Yes, there was a time that lung cancer used to be rare and it wasn’t until the 1950s that five studies were published showing an association between tobacco use and lung cancer in men. Guess who disputed this evidence? Yes, you guessed it right- Cigarette manufacturers and surprisingly 1/3 of US doctors also didn’t buy into this “case against cigarettes”. Though we take this finding for granted, it took epidemiologists a long time to dissect big data to identify and establish and to some extent drive this association into our society. It is also indirectly because of the work of epidemiologists’ that the label on cigarettes has changed from “For a Treat, instead of a treatment, enjoy Old Gold’s fine and friendly tobaccos” to “Smoking can kill you”.

Epidemiology-present and the future:

  1. Epidemiology can make future predictions and give early warnings

You know how you always wish you can see into the future? Well, Epidemiology is a science that can do that, subsequently providing intelligence for future health actions. Using quantitative approach and statistical models, epidemiology is a powerful tool that can describe patterns in viral or bacterial movement, study how transmittable a virus can be and how it differs across different populations including gender and age group.

Remember: early signal of outbreaks leads to rapid public health actions which can prevent and contain outbreaks.

  1. Epidemiology is with you at every step of your life

Yes, epidemiology is that cool! I can confidently say that there is no life science where epidemiological approaches cannot be applied. Do you know why women don’t drink (well…most women) while they are pregnant? Because drinking during pregnancy was associated with brain damage to the child (epidemiology in preventive geriatrics).

Epidemiology is also a field that evaluates health programs and implements effective interventions such as screening programs. It is through this that the health world was able to identify risk groups for breast cancer and implement screening programs for women at risk (age above 45).

3. Epidemiology improves quality of health practice

A hub of registries in high-income countries can be used as a model for low-income countries or countries that don’t have such fine-tuned registries. This is testimony that epidemiology is systematic and has wider applications. In an era where low-income countries are fighting both communicable and non-communicable diseases, these type of registries that already exist in high-income countries can provide meaningful insights into ways of tackling health problems and improving quality of health practices as well as decrease inequalities between different sub-groups.


This is why I am studying Epidemiology- to make meaningful contributions by improving the health of the population. Whether you are pursuing Epidemiology or not, you can’t help but marvel at the strength of the tools that Epidemiology uses to positively impact the globe.

You can reach me at Nuhamin.Petros@stud.ki.se

Stay tuned, lovely people!

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