Epidemic vs. Pandemic: What’s the Difference between Pandemic vs. Epidemic?

Last Updated on December 8, 2023

When listening or reading public health news, you might come across two words, epidemic vs. pandemic. Both of them have the same root and refer to diseases, but there is a big difference between them. In order to better understand the news and be fully aware of what is happening in the world, it’s important to know it.

Epidemic vs. Pandemic: Overview

Key Takeaways

  • An EPIDEMIC describes a problem that grew out of control.
  • A PANDEMIC is something more global, affecting the whole country or even the whole world, and relates to the disease being widely spread geographically.

Epidemic vs. PandemicPin

Epidemic vs. Pandemic: the Definitions

With every disease, there is a certain number of people that scientists and doctors except to get sick at a specific period of time. When the actual number of people who catch the disease suddenly becomes a lot larger than it was expected, this is an epidemic. However, when the disease spreads across the whole country, continent or world and takes away millions of lives, the term “epidemic” is too light to describe what is happening. Thus, an epidemic becomes a pandemic.

Sometimes it might take a few years or even decades for the disease to spread across the globe, but sometimes just a couple of months will be enough. Still, of course, not every epidemic will become a pandemic. If public health officials react quickly and develop a correct plan of action, they will be able to stop the virus from spreading all over the world. In some other cases, the virus itself will become weaker for some reason, and once again, a pandemic will be prevented.

There are many devastating examples of pandemics that took millions of lives, but one of the worst is HIV: since 1982, it has already killed about 40 million people. One other heartbreaking example is the cholera pandemic that lasted from 1816 up until 1824, affecting people from all over Asia and Europe and taking over 40 million lives in these eight years. In 1918, the Spanish flu pandemic, though it only lasted for a year, killed more than 50 million people.

Defining Epidemic

An epidemic is when the number of disease cases rises above the expected threshold within a specific geographical area. It’s characterized by:

  • Controlled spread: While significant, its reach is usually within a single community or region.
  • Unexpected rise: It represents a sudden increase in cases beyond what is typically observed.

Defining Pandemic

pandemic, in contrast, denotes a disease affecting a wider geographical area, often worldwide. Key features include:

  • International impact: Crosses international boundaries, touching numerous countries or continents.
  • Extensive spread: Signifies an escalation in disease prevalence beyond an epidemic scale.

Historical Examples

Throughout history, we have witnessed many infectious diseases that have dramatically impacted societies. Some have remained localized, constituting epidemics, while others have spread across continents, escalating to pandemics.

Notable Epidemics

  • Yellow Fever: This epidemic has struck numerous times throughout history, with outbreaks occurring in various regions, including the American South.
  • Polio: The disease peaked in the United States in the 1950s before a vaccine was introduced, leading to thousands of paralysis cases annually.

Notable Pandemics

  • 1918 Influenza Pandemic (Spanish Flu): This pandemic affected a third of the world’s population and caused the deaths of 50 million people worldwide.
  • COVID-19: Emerging in late 2019, this disease caused by the novel coronavirus (SARS-CoV-2) has resulted in a significant global impact, affecting millions and continuing to evolve.

Epidemic vs. Pandemic Examples

Epidemic Examples

  • Health officials declared an epidemic after the sudden rise in flu cases.
  • The epidemic of obesity is a growing concern in many countries.
  • The government launched a campaign to combat the epidemic of opioid addiction.
  • Scientists are studying the factors that contributed to the epidemic‘s spread.
  • The 1918 influenza epidemic is considered one of the deadliest in history.
  • Public awareness is crucial in preventing the escalation of an epidemic.
  • The epidemic curve showed a peak in cases during the winter months.

Pandemic Examples

  • The COVID-19 crisis was declared a pandemic by the World Health Organization.
  • During the pandemic, many people worked from home to reduce the spread of the virus.
  • The 1918 Spanish flu was one of the most devastating pandemic events in history.
  • Governments around the world imposed travel restrictions to control the pandemic.
  • The pandemic led to a global shortage of personal protective equipment for healthcare workers.
  • Scientists raced to develop a vaccine in response to the pandemic.
  • The economic impact of the pandemic was felt by businesses both large and small.

Epidemic vs. Pandemic: Practice and Exercises

Worksheet: Understanding Epidemic vs. Pandemic

Instructions: Below is a list of disease outbreaks. For each one, decide whether it is an example of an epidemic or a pandemic Place a tick (✓) in the corresponding column for your answer. 

Disease Outbreak Epidemic Pandemic
Influenza in the United States, 1918    
HIV/AIDS in San Francisco, 1980s    
COVID-19, as of 2020    
SARS in Hong Kong, 2003    
Ebola in West Africa, 2014-2016    
Zika virus in Brazil, 2015-2016    
Measles in Samoa, 2019    
Cholera in Haiti, 2010    
H1N1 Swine Flu, 2009    
Dengue Fever in Thailand, 1980    


  1. Pandemic – The 1918 influenza outbreak affected people worldwide, making it one of the deadliest pandemics in history.
  2. Epidemic – While HIV/AIDS became a global issue, the reference to San Francisco in the 1980s indicates a localized outbreak, which classifies it as an epidemic.
  3. Pandemic – COVID-19 spread globally, affecting millions of people across multiple continents, and was officially declared a pandemic by the World Health Organization (WHO).
  4. Epidemic – SARS was primarily contained to Hong Kong and some other parts of the world, but it did not reach the level of a pandemic.
  5. Epidemic – The Ebola outbreak was severe but was mostly contained within West Africa, so it is considered an epidemic.
  6. Epidemic – The Zika virus had a significant outbreak in Brazil and spread to other countries, but it did not reach the criteria to be classified as a pandemic.
  7. Epidemic – The measles outbreak in Samoa was a significant event localized to that region, making it an epidemic.
  8. Epidemic – Cholera in Haiti was a severe localized outbreak, which classifies it as an epidemic.
  9. Pandemic – The H1N1 Swine Flu spread across multiple countries and continents, affecting a large number of people, thus it was declared a pandemic.
  10. Epidemic – Dengue Fever in Thailand in 1980 was a significant outbreak but was localized to Thailand, classifying it as an epidemic.

Frequently Asked Questions

What are the characteristics of an epidemic?

An epidemic is characterized by the rapid spread of a disease within a specific geographic area or population. It’s marked by an infection rate that exceeds the normal expectancy.

How does a pandemic differ from an epidemic in terms of spread and impact?

A pandemic is an epidemic that has spread over multiple countries or continents, usually affecting a large number of people. The impact is more widespread and typically exerts considerable strain on health care resources globally.

Can you provide an example of a disease that is considered endemic?

Malaria is a common example of an endemic disease, as it is consistently present within certain regions, particularly in sub-Saharan Africa.

What factors contribute to a disease being classified as a pandemic?

Key factors include the disease’s ability to spread rapidly across a wide geographical area and infect a significant portion of the population, often due to a lack of preexisting immunity.

How did COVID-19 transition from an epidemic to a pandemic classification?

COVID-19 was classified as a pandemic when it spread across the globe quickly, affecting a large proportion of the population, and demonstrated sustained transmission within communities.

What public health responses are typically seen with an epidemic?

With an epidemic, responses often include localized measures such as quarantine, contact tracing, vaccination drives, and public awareness campaigns to contain and manage the disease spread.

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