Epidemic? Pandemic? Endemic? 

I want to start by defining the difference between an epidemic, a pandemic, and an endemic. According to CDC (Centers for Disease Control and Prevention), an epidemic is a sudden increase in the number of cases of a disease abnormally in a population. Pandemic is the exponential growth of a disease where the number of cases increases more than the day before by the definition of WHO (World Health Organization). An endemic is when a disease is constantly present limited to a particular region. Usually, the spread of an endemic is predictable.

Pandemic of the 19th Century

The influenza virus was once a pandemic in the late 19th century. With the increased transportation routes during the industrial age, the influenza virus’s rapid spread was observed. Notably, the influenza virus still causes hospitalizations and deaths globally. CDC estimated between 39 million to 56 million flu cases and 24 thousand to 62 thousand deaths caused by the influenza virus in the US for the 2019-2020 flu season. (1) Another influenza pandemic is the commonly known Spanish flu causing over 50 million deaths. Nowadays, influenza is considered an endemic still affecting populations during the flu seasons.

What about COVID-19?

The pandemic we are experiencing, the coronavirus pandemic is currently causing lockdowns, isolation, social distancing, deaths, and economic stress in many countries. Will this stay the same? Or will it go away? According to scientists, the answer to neither of these questions is yes. Researchers foresee that COVID-19 could turn into an endemic such as seasonal flu. 

A survey conducted by Nature inferred that “the coronavirus is here to stay”. More than 100 immunologists, infectious disease researchers, and virologists were asked if coronavirus could be eradicated. Nearly 90% of the researchers stated that they think the coronavirus will be endemic. However, this does not mean the virus will keep causing lockdowns and deaths in this scope. Although the coronavirus could be classified as an endemic because it has already spread around the globe, it is still considered a pandemic because of the rapid increase in numbers. 

It is unclear that for how long immunity is maintained after being infected with SARS-CoV-2. The weakening of the immunity against COVID-19 is one of the reasons scientists think that this will turn into an endemic.  Besides, it is possible that the virus can evade the immune system by mutations over time. Because of this, the SARS-CoV-2 could become seasonal where we encounter the virus during childhood and gain immunity. (2) 

To keep the coronavirus under control, we should all do our part meaning practicing social distance, isolation, wearing masks, getting vaccinated until enough people are immunized by either natural immunity or vaccination. 

Living in a pandemic means being cautious of our health more than ever. FluAI provides you analysis and personal suggestions when you feel like coming down with the flu, or a cold. Download now and start with your free analysis!


  1. 2019-2020 U.S. Flu Season: Preliminary In-season BURDEN ESTIMATES. (2020, December 03). Retrieved April 10, 2021, from https://www.cdc.gov/flu/about/burden/preliminary-in-season-estimates.htm
  2. Phillips, N. (2021). The coronavirus is here to stay — here’s what that means. Nature, 590(7846), 382-384. doi:10.1038/d41586-021-00396-2


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