The blurry distinctions of endemic, epidemic and pandemic
The words epidemic and pandemic both refer to the very real threat of infectious
diseases. They have been used in medical literature and elsewhere for hundreds of years but it is
only now that we are considering how they are different. In fact, they have been mistakenly used
interchangeably in the past. However, the onslaught of the corona virus disease, also known as
CoViD-19, in the world forced us to be aware of what these words whose meanings are
sometimes a blur even to medical practitioners, truly meant.
The world today is reeling from the effects of an infectious disease that has been going on
for over two years. At the moment, Worldometers reports that over 310 million people had been
infected with CoViD – 19 worldwide. Of this number, over 5.5 million have died. The World
Health Organization (WHO) declared that the disease is a pandemic of global scale.
Meanwhile, in 2017, two years before CoViD – 19 was ever a word in our vocabulary, a
modern-day plague plagued the small nation of Madagascar. In that outbreak, 209 people died
and 2417 were infected. The WHO referred to what happened as an epidemic.
Two infectious diseases two years apart. One was called a pandemic while the other was
called an epidemic. What is the difference? What are the tell-tale signs that an infectious disease
is an epidemic and not a pandemic? Can the blurry lines in the meaning of these words ever be
cleared? Let us find out.
The Tell-tale Signs
Knowing what the words “pandemic” and “epidemic” really meant is not only timely
and relevant. It is also essential if we are to better understand public health concerns. With all the
so-called CoViD-related news, features and opinions circulating in the mainstream and social
media and the often-confusing pandemic response policy trumpeted all around, we cannot afford
to be clueless and ignorant about them.
But where do we begin? How shall we start?
Crucial to understanding the meaning and extent of the usage of both “epidemic” and
“pandemic” is first defining two other important words related to them – endemic and outbreak.
Let us, therefore, first consider them.
An endemic is a disease that affects the population of a particular group of people or
community in a country (What’s the difference, 2020). It only affects a small portion of the
general population and breaks out at specific seasons on the same vicinity. It usually does not
cross the borders of that geographical area. The disease is present constantly and is just confined
there.
However, when there is an occurrence of increase in the number of endemic cases in a
community, and this increase is statistically greater-than-expected, there is said to be an
outbreak. Moreover, there is also an outbreak if a new case of the same infectious disease has
started in another area or community. If this spread of the disease goes out of control, it can lead
to an epidemic. So, before there will ever be an epidemic or a pandemic, there will first be an
occurrence of an endemic followed by an outbreak in a community.
Now that we have considered where an epidemic and by extension, a pandemic evolves
from, we can look into how we can clear the blurry lines of meaning between an epidemic and a
pandemic. This way we can identify what they really meant and describe how they are different.
Clearing the blurry lines of meaning: Epidemic and pandemic defined
An epidemic is a disease that affects a larger segment of the population of a community
and spreads to other communities in a region or a country. An endemic can become an outbreak
and an outbreak can become an epidemic if the infectious disease spreads actively to neighboring
communities at a fast rate and if the infections are somewhat higher than usual. This is like what
happened in Wuhan, China when an outbreak of a new corona virus disease was identified. It
quickly spread to other communities and became an epidemic.
Now when an infectious disease crosses the border of the country of origin and spread to
another country or continent like what happened with CoViD-19, the epidemic becomes a
pandemic.
Since the world today is in a state of global pandemic, let us put “pandemic” into
perspective and learn more about it. How is it defined? What examples of pandemics can we
mention from history?
In a scholarly article published online, Biggers (2020) traced how the word pandemic was
first defined. She mentioned that in 2010, a year after the discovery of the H1N1 virus, the WHO
declared that it was already a pandemic. The international body defined the word, “pandemic” at
that time as the spread of an infectious disease in a global scale.
According to the Centers for Disease Control (CDC), the influenza pandemic of 1918
was “the most severe pandemic in recent history” (Influenza, n.d., pa. 1). This infectious disease
was caused by an H1N1 virus which originated from birds. The estimates show that at that time,
between 1918-1919, one third of the world’s population got infected and about 50 million died.
History shows that epidemics and pandemics are not modern-day phenomena. Jarus
(2021), in an article for Live Science, traced the history of the worst epidemics and pandemics
that the world had experienced. Some of these brought down entire civilizations and once
powerful nations. Many of them killed millions. These, however, are not only part of our human
history. They threaten our very existence even now.
Epidemics, Pandemics and the Advance of Epidemiology
Epidemics and pandemics are not a thing of the past. Our world’s current bout against
CoViD-19 shows that even now, in spite of modernity and advanced human development,
infectious diseases emerge without warning from our natural environment. Thankfully, our
advances in the science of epidemiology gives us a fighting chance against these diseases.
In Merriam-Webster (n.d.), epidemiology is defined as “the branch of medical science
that deals with the incidence, distribution, and control of disease in a population. It is further
defined as “the sum of the factors controlling the presence or absence of a disease or pathogen.”
It is through advances in this field of medicine that we are now positioned to better
understand what epidemics and pandemics really are as well as how we distinguish them no
matter how blurry their definitions are.
References:
Biggers, Alana (2020). How is a pandemic different from an epidemic? In Healthline com. 30
April, 2020. https://www.healthline.com/health/pandemic-vs-epidemic#what-is-a-pandemic
Jarus, O. (2021). 20 of the worst epidemics and pandemics in history. In Live Science.com. 16
November, 2021. https://www.livescience.com/worst-epidemics-and-pandemics-inhistory.html
Merriam-Webster, (n.d.). Epidemiology. In Merriam-Webster.com dictionary. Retrieved January
10, 2022 from https://www.merriam-webster.com/dictionary/epidemiology
Intermountain Healthcare, (2020). What’s the difference between a pandemic, an epidemic,
endemic, and an outbreak? https://intermountainhealthcare.org/blogs/topics/livewell/2020/04/whats-the-difference-between-a-pandemic-an-epidemic-endemic-and-anoutbreak/