Endemic does not mean harmless

It means that disease is present in a population at a relatively predictable level.

5 minute read

Endemic does NOT mean harmless. A common misconception throughout the pandemic is the notion that once we shift from “pandemic” to “endemic” that also means COVID-19 is no longer dangerous. That is simply not the case.

Endemic in the context of infectious diseases refers to when a disease is always present in a given population in a given geographic area. It also means that infection rates of a given pathogen are predictable and generally stable. Stable also doesn’t mean low - you have an endemic disease that infects and potentially kills hundreds of thousands (or even millions) of people every year. Stable in this setting refers to a characteristic of consistency over a period of time.

It simply means that we can predict what may affect case rates, or if there is seasonality with the spread of disease, instead of being sideswiped with surges that we did not anticipate.

Many diseases are endemic within human populations. Influenza, “common cold” viruses, malaria, HIV, polio, and tuberculosis are all endemic. Smallpox was endemic until we eradicated it through vaccination. 

Endemic tells us nothing about the disease severity of the pathogen in question either. We can have extremely debilitating and fatal illnesses that also happen to be endemic. It simply means it is present among populations and it is not an epidemic. More than that, the shift to endemic from pandemic is a gradual process; it is not like we wake up one day, flip a switch, and suddenly we are in the endemic phase. This is all due to varying factors that have different weights in different situations.

So what do the terms epidemic, outbreak, and pandemic mean?