Difference Between Pandemic and Epidemic


While the idea of an epidemic and pandemic may seem quite similar to most of us, since they are both terms that are used to refer to the outbreak of disease, in reality, they are radically different concepts. There are a number of crucial dissimilarities between the two that must be discussed in depth in order to develop a greater understanding.


An epidemic occurs when a disease or illness is spread to a wide range of people in the same area within a very short period of time. The spread of infection to many people rapidly can also be characterized as an epidemic.

An example of an epidemic that most of us would be familiar with is the SARS epidemic (which is also known as severe acute respiratory syndrome) that spread back in 2003, taking the lives of over 800 citizens throughout the world.

This may seem like the same concept as a pandemic to many, but the difference lies within the surface area covered. An epidemic will simply not affect as many people as a pandemic will, even in situations where they may appear to be similar.

Another factor that often serves to confuse outside observers is the idea that an epidemic can begin in one place, and by the time it has moved to another, it is now known as a pandemic. The outbreak becomes known as an epidemic once it has infected more people than the norm in one particular area.

Once the epidemic begins to move onto other countries and areas of the world, the classification changes. When an outbreak is specific to a certain area or can be attributed to a specific region of the world, this is when it is known as an epidemic. As it begins to spread and affect citizens all over the world, it becomes a pandemic.


Pandemics are unable to be contained by natural borders and can spread anywhere in the world. Most pandemics are particularly problematic, because they are typically incurable and are able to spread because they have exposed an area of the human immune system that does not have immunity, even after having been vaccinated.

This causes the infection or disease to spread far and wide and affect people no matter what country they reside in. Diseases may start in foreign continents such as Asia and Africa, but when they do not remain in those areas and begin to make their way across the pond, the classification changes.

Pandemics occur when the virus is spread very easily from person to person. This usually happens when viruses are spread simply by sneezing or coughing near a person who is in a confined space. The easier it is for the virus to spread, the more likely it is to be classified as an pandemic, as opposed to an epidemic.

Another defining characteristic of a pandemic is that the virus will begin to become a catalyst for the development of severe illnesses around the world and put more lives in danger. Pandemics tend to be exacerbated more in the modern era, because of the ease and convenience of air travel.

While some believe that we are seeing more pandemics in the modern era because of less cleanliness or mistakes being made by other cultures and regions, the reality is that it is extremely difficult to keep an epidemic contained. The epidemic will inevitably travel and become a reality for those who are living in other areas.


The faster the epidemic spreads, the faster it will be categorized as a pandemic. After the virus has been reclassified as a pandemic, there are six different stages, with the first stage being the lowest and the sixth stage ranking as the most serious.

Phase 1 involves no human infections and the virus is contained to just animals. Once the virus has begun to travel from its animal hosts and has started to infect humans, this is Phase 2. Phase 3 is when the virus starts to become problematic, infecting larger clusters of human beings, especially small children and the elderly.

These beginning three stages are different from the following three, because it is at this time that the virus can still be categorized as an epidemic, which causes a certain level of confusion. While a virus remains in the first three stages, it can be still be called an epidemic.

The fourth stage can also be fuzzy, since the risk of infection has increased, yet a pandemic is not certain. The disease is still localized in one area, but experts may believe that the infection has a strong possibility of spreading. As long as a small level of uncertainty remains, the infection stays at Phase 4.

Phase 5 is when the disease begins to spread more easily among humans in the same region or country. The illness still may not be known as an pandemic during this time, depending upon the opinions of health experts. Phase 6 is when the virus has become full blown and is now officially a worldwide pandemic.

It can be difficult to discern the difference between an epidemic and a pandemic and the manner in which these two separate forms of disease are discussed and assessed can lead to further confusion. While an epidemic can become a pandemic, a pandemic cannot become an epidemic and the most crucial lies in the surface area that each of the infections is able to cover.