By Ravali Yenduri | Last Updated: March 28, 2021

Image by: Brett Dashevsky

What is a Pandemic?  

A pandemic is the spread of disease over a wide area that affects a large portion of the population. 


Key Takeaways

  • A pandemic is an epidemic on a MUCH larger scale.

  • A pandemic is classified as the most severe disease outbreak.


Endemic → Epidemic → Pandemic 

An endemic is the constant presence of disease in the population and includes cancers and cardiovascular diseases. An epidemic is the occurrence of disease in greater numbers than what is normally expected in the population, such as obesity in the U.S. A pandemic is an epidemic that quickly spreads across multiple countries. 

Who calls the shots?

The World Health Organization declares an outbreak as a pandemic. The WHO is responsible for tracking an outbreak on a global scale and has a pandemic preparedness plan consisting of six phases. The WHO plays an important role in communicating the severity of outbreaks so countries can prepare and plan. For example, the WHO declared the coronavirus outbreak as a global pandemic on March 11, 2020, at which point the disease had spread across 114 countries. 

History of Pandemics

The bubonic plague was the largest pandemic to date, killing approximately 30-60% of Europe’s population. Smallpox was the second-largest pandemic, with an annual death toll of 400,000 people. Luckily, we now have a vaccine for smallpox. The current pandemics include HIV/AIDS and COVID-19.

Prevention of Disease Spread 

How can we prevent disease transmission? 
  1. Quarantining, or remaining socially isolated. 

  2. Washing hands frequently, coughing into your elbow, 

  3. Wearing a mask in public, and 

  4. Refraining from touching your face are all ways to protect yourself and others from infection.


Outside the Huddle


Reviewed by Geetika Rao, MPH | Edited by Nidhi Mahagaokar, MPH | Fact checked by Julia Radossich, PA-C