Courtesy of http://doubledribble.wordpress.com
According to the World Health Organization (WHO), epidemiology can be defined as:
“The study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems” (WHO, 2011).
But let’s break this down even further!
Epi-demi-ology
Epi – “upon”
Demi – “people”
Ology – “the study of”
Overall, epidemiology has five main goals (Gordis, 2009, p. 3):
- Identify the cause and risk factors behind a disease
- Determine how widespread the disease is in a society
- Analyze the natural history of a disease
- Evaluate preventive measures, different forms of medical treatment, and types of health care delivery
- To provide assistance and insight for composing public policy affecting health promotion and disease prevention
Before I started my studies in epidemiology, I simply thought it was concerned solely with diseases and their effects on populations. However, the study and profession of epidemiology reaches a much greater spectrum than this. As someone who is deeply interested and passionate about health policy, I was pleasantly surprised to discover the importance of epidemiology in shaping and influencing public policy. This fact makes the study incredibly important and powerful in the world of health care. In truth, epidemiology is all around us. From investigating food outbreaks, to determining the source of epidemic outbreaks, to ensuring that our drinking water is pure and free of pathogens, to distributing and promoting different forms of prevention, such as vaccination campaigns (see H1N1 Flu Outbreak of 2009 below), epidemiology is everywhere keeping us safe.
Being such an important aspect of the broader specialty of public health, epidemiology has done more to extend the average human life expectancy and improve human life quality overall than any single cure or treatment. As someone who is passionate about health policy, one area that I am particularly fond of is preventive medicine and practices. Epidemiology is very involved with preventive medicine, as its scientists are always looking for ways to make preventive care smarter and more efficient by using empirical evidence gathered throughout communities, states, or even countries. After all, as Hippocrates, the father of medicine, once stated:
“It is always better to prevent a disease than it is to cure one.”
Courtesy of the University of Illinois-Chicago http://www.tneel.uic.edu/tneel-ss/demo/impact/frame1.asp
This image displays the top 10 leading causes of death in the USA from 1900 and 1997. Notice the large prevalence of infectious diseases in 1900 and the emergence of chronic diseases in recent years. This image demonstrates how the power of epidemiology has changed our world. Whereas infectious diseases are spread from the environment (such as a swimming pool in the early 20th century), thus allowing the agent (for instance Poliomyelitis, or the polio virus) to be spread either directly to the host (the person) or indirectly via a vector (for instance, a mosquito transmitting malaria). Chronic diseases on the other hand, are an entirely different type of problem. Many times they are a direct result of lifestyle, including a sedentary lifestyle, poor nutrition, excessive alcohol consumption and tobacco use (Department of Health and Human Services, 2010).
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An example of preventive medicine via epidemiology from my (our) world:
The H1N1 Flu Outbreak of 2009
When the H1N1 flu outbreak took place in 2009, I was an undergraduate student at the University of Washington. At this time, I was also a part-time volunteer in the trauma surgery unit of the Harborview Medical Center in downtown Seattle. As people became concerned, as did I, it was soon discovered that there was a low supply of H1N1 vaccine available for the general public. With the supply low, this meant that the remaining vaccine had to be rationed intelligently, with the most susceptible individuals coming first.
Click here to hear about the H1N1 vaccine shortage of 2009 (courtesy of NPR)
Some of the first people to receive the vaccine were government employees, and I know this because I have a close friend in the FBI, and I remember her and her family being vaccinated before anyone else was at that time. I remember thinking that it was unfair that they had preference over the rest of us, but I soon realized that they were vaccinated first to protect and serve the rest of us if the flu outbreak got out of control.
Being both a college student and especially a hospital volunteer moved me up the priority list to receive the vaccination, which made me very happy. Being a volunteer always pays off, life has a funny way of rewarding us with good deeds sometimes. I am a huge believer in prevention, especially when it comes to the promotion of vaccination programs, and I am always eager to receive my flu shot as soon as it is available in the fall. Technically, from an epidemiologist’s point of view, I would be referring to solely primary prevention. In fact, there are three forms of prevention, all of which are essential to the promotion of health and the prevention of disease.
Primary Prevention: Preventing the initial development of a disease in an individual who is currently well (for instance vaccinations).
Secondary Prevention: Early detection of existing disease to reduce severity and complication (for instance mammograms).
Tertiary Prevention: Reducing the impact of the disease in individuals who have already been diagnosed with the respective disease (for instance rehabilitation services).
(Gordis, 2009, p. 6)
However, something that really upsets me is when individuals fail to get vaccinated due to ignorance and apathy. I have a friend who refuses to get the flu shot because he is convinced that it is a waste of time. He claims that the shot gives you the flu disease (which is impossible since the various versions of the virus within the vaccine are all inactivated or killed) and always references older relatives. First of all, if a person is having a bad reaction to the shot, it is probably because the person is allergic to the many chemicals in the vaccine, or the person is allergic to eggs, since the virus is grown in chicken eggs (a technique that hasn’t changed or been improved upon greatly since its inception). However, my friend just refuses to be responsible and get the vaccine, partly out of ignorance and stubbornness, and partly due to distrust of the medical community. Nonetheless, by obtaining the vaccine, he would be protecting both herself and others around her.
Courtesy of http://othellooutlook.com/
Granted, thanks to the phenomenon known as herd immunity, which states that as long as a large proportion of a community is immunized to a specific disease, the spread of that communicable disease should be minimized, and this should be enough to protect the community as a whole. However, I still think it is our responsibility as members of society to get vaccinated for both our and society’s sake (assuming that the person doesn’t have negative reactions to vaccinations).
Also, I am in favor of the recent Patient Protection and Affordable Care Act and its intention to make certain evidence-based preventive services, including vaccinations, free of charge under most new health insurance policies. To see more details on this click HERE.
What do you think about this? Are people being irresponsible socially and personally when they fail to get immunized? Any suggestions on how we as a nation can further promote the use and many benefits of vaccinations?
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Department of Health and Human Services. (2010, July 7). Chronic Disease Prevention and Health Promotion. Retrieved February 9, 2011, from Centers for Disease Control and Prevention: http://www.cdc.gov/chronicdisease/overview/index.htm
Gordis, L. (2009). Epidemiology (4th Edition ed.). Philadelphia, PA, USA: Saunders Elsevier.
World Health Organization. (2011). Epidemiology. Retrieved February 8, 2011, from World Health Organization: http://www.who.int/topics/epidemiology/en/
Epidemiology...it's everywhere! 
Article was very informative and the presentation was well done!
I think this is an excellent presentation. It seems very thorough and is written so that someone who is not in the health field can understand and relate to it. Well done, Bravo!!!
This is a clear, informative, and well written article on Epidemiology. I learned more than I ever thought I could on the subject. I am pleased to really know what this word means in full. I will print this article to help retain this information and share with others.
Thank you for your comments! I do always enjoy figuring out what word-roots are contained in different words, whether they are Latin or Greek, because it provides a clearer definition of the word.
Are people being irresponsible socially and personally when they fail to get immunized?
I don’t think it’s such a simple question to answer anymore. Not when we vaccinate for things like chicken pox that didn’t cause high mortality or long term, severe sequela. It was a good public health measure when you consider the financial lost to society from missed work do to parents having to stay home with their sick child. But was this the best decision for our immune system in the long term? There are studies being done in the role of being exposed to allergens and Asthma. There may be a role in getting exposed to different diseases in evolution. We don’t know. Now I recommend my patients get vaccinated for chicken pox because the chances of them getting chicken pox as children is very low due to herd immunity. That means there is a chance they could get chicken pox as adults if they are not vaccinated, which can be a more severe illness.
I would like to comment on this statement: “There may be a role in getting exposed to different diseases in evolution.” While I think this is really true in theory, I don’t think it is feasible in reality. I personally don’t want to risk my own life for the sake of humans living thousands of years from now, who knows if there will even be humans living thousands of years from now. Plus, economics teaches us that people act in their own self interest, so obtaining a vaccine is in both their interest as well as the population’s interest. Like Carol states below, we need to motivate people to get vaccines, because it is really in their best interest as well as society’s. What we need is better education on the matter!
I agree and promote vaccinations. My point was that chicken pox wasn’t really putting anybodies life in danger! Should we be using this money on educating patient on vaccinations that can really put the whole community in danger? Like Gardasil! Many women still die from cervical cancer. Or diabetic education. How many people die from chicken pox?
If we don’t care about human’s being thousands of years from now….why recycle?
We should promote all forms of vaccinations, but emphasize the most imperative ones.
I can’t get sick or die from recycling….but I could get sick or die from vaccination abstinence. The costs involved in recycling are much lower than bearing the blunt of a disease.
I note that senility was among the major causes of death in 1900 but what is now called dimentia does not register in the 1997 table. Regarding “Primary Prevention: Preventing the initial development of a disease in an individual who is currently well (for instance vaccinations).” Interesting to note that sometimes government policy runs counter to good health and kills. Note the severe increase in malaria, a deisease that was pretty much irradicated until the UN stepped in and banned DDT. Some say as many as 50,000,000 Africans have died over the years as a result of bad health policy in the name of environmentalism. I recommend minimal government intervention in our health-for health’s sake.
Your passion for this subject is obvious! With regard to our social responsibility to receive immunizations, the social responsibility topic is a basic division in our country, including politically. But one subject that transcends this division is a person’s health. By creating an incentive for the public to take inoculations, maybe we also begin to transcend the political gap on social responsibility. How do we do this? The key is incentive/motivation. Very little happens in the world without incentive. Let’s have a further discussion on what that incentive should be!
Enjoyed the post. Years ago I first encountered the term at NC State Univ. with more of a biological tilt — that epidemiology was a triangle with the animal or host, the environment, and the causative agent at each of its corners and the interconnecting lines forming the interactive two-directional pathways of effect. I see that concept remains but the details in the medical arena may have morphed some.
“FLULAVAL is a vaccine indicated for active immunization against influenza disease caused by influenza virus subtypes A and type B contained in the vaccine… This indication is based on immune response elicited by FLULAVAL, and there have been no controlled trials adequately demonstrating a decrease in influenza disease after vaccination with FLULAVAL”
Affluria and Fluzone read just the same in their package inserts (2010)