Though not yet considered endemic, COVID-19 is here to stay


Dear Doctors: We don’t hear about COVID-19 that much these days. The words I keep hearing are endemic, epidemic and outbreak. Can you explain what the differences are? Is COVID-19 over?

Dear Reader: You’ve asked several questions that, based on the mail we’re getting, are on the minds of a lot of people. The last two-plus years of dealing with the COVID-19 pandemic have taken a steep toll on each of us. It’s hardly surprising that everyone is eager to move on. In a recent survey, the majority of people -- more than 70% -- said it’s clear that the coronavirus is here to stay. They believe it’s endemic, and that it’s time to accept it as a part of daily life.

And that brings us to the easier part of your question, which is defining the terms you have asked about. They fall into the branch of science known as epidemiology. That’s the study of how, and how often, disease occurs and spreads in groups of people.

Let’s begin with the word “outbreak.” That refers to a sudden and ongoing increase in the number of cases of a disruptive disease, beyond what is normally expected. An outbreak can occur within a specific group of people, or it can be observed in a limited geographic area. If an outbreak begins an uninterrupted spread beyond its initial population and geographic area, it is then referred to as an “epidemic.” Should the disease involved in an epidemic cross multiple international borders and spread worldwide, it is then classified as a “pandemic.” To put it simply, a pandemic is a global epidemic.

Elizabeth Ko, MD and Eve Glazier, MD

And that brings us to the concept of an “endemic” disease. This is a disease that has become established in a certain area, or among a certain group of people, and whose rates of circulation have become somewhat predictable. The flu and the common cold, each of which begin to circulate with increased frequency during the winter months, are endemic in the United States. In some parts of the world, malaria is considered to be endemic.

When it comes to COVID-19, the lifting of pandemic restrictions in much of the U.S., as well as a wide-spread abandoning of precautions such as wearing masks and limiting gatherings, has led people to treat the disease as endemic. Health officials say that as of yet, it is not. But, as Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, recently said, the U.S. appears to be entering a “transitional phase” of the pandemic. He was referring to the fact that the rates of both hospitalizations and deaths are dropping. This is due, in large part, to the build-up of immunity through vaccinations, boosters and infection.

However, that immunity is to severe illness and not to getting infected in the first place. In fact, infections continue. The Centers for Disease Control and Prevention recently estimated that roughly 60% of the population in the U.S. has now been infected with the coronavirus. And that leads us to your final question. Although we are gradually learning to manage and live with COVID-19, the reality is the virus is here to stay.

To learn more about the vaccines and for the latest information visit UCLA Health's COVID-19 Vaccine Info Hub.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)