What you should know about the omicron variant

Omicron—a variant of the COVID-19 virus that was first identified in South Africa—is now the dominant strain of coronavirus in the United States, according to the Centers for Disease Control and Prevention (CDC).

But what do we really know about this new variant? And how concerned should we be?

To answer these questions and break down what we know so far, Daniel Diekema, MD, infectious disease specialist with UI Health Care, explains that although much is still unknown, there are things we can do now to protect ourselves and others.

What is a variant? How do we know if a variant is concerning?

“All viruses change over time, and SARS-CoV-2 (the virus that causes COVID-19) is no different. So, virus ‘variants’ are expected to be identified over time. A variant is considered ‘concerning’ (a ‘variant of concern’) if it is more easily spread, causes more severe illness, evades the effectiveness of vaccines and treatments, or if it is harder to diagnose with our current COVID-19 tests.”

How does the omicron variant compare to the delta variant?

“Omicron spreads more easily and quickly than the delta variant, and it is now the most common variant in the United States. There is also evidence that some monoclonal antibody therapies might be less active against omicron. We should get more information about this in the next several weeks. We do know that our current tests will still detect the omicron variant.”

Are the symptoms of omicron different?

“The early reports do not suggest that the symptoms of omicron will be very different from those of the other variants. However, we won’t know for sure for another few weeks or months.”

Will our existing vaccines (Moderna, Pfizer-BioNTech, Johnson & Johnson) protect us from omicron?

“Existing vaccines provide protection against severe disease due to the omicron variant, as they have against all the previous variants. However, omicron seems better able to cause mild or moderate infections among vaccinated individuals than the previous variants. Receiving a booster dose of Moderna or Pfizer-BioNTech vaccines (regardless of which vaccine you received initially) is very important to get the best protection against omicron. New vaccines that are specifically designed for the omicron variant are in development but are not likely to be available for at least 3-4 months. So, at this time, your best protection is a booster dose.”


Wearing a mask and social distancing—in addition to receiving a COVID-19 vaccine—are the best ways to slow the spread of the COVID-19 virus.

Is UI Hospitals & Clinics testing for the omicron variant?

“Yes, our lab tests will detect the omicron variant, and we continue to perform additional specialized tests (in collaboration with our State Hygienic Laboratory) to sequence the viruses we detect so that we can determine how prevalent the omicron variant is in our community”

When will we know more about omicron?

“We are learning more every day about omicron, but it will take at least two to six weeks to have more reliable information about the impact that omicron is likely to have on the COVID-19 pandemic.”

What is the best way to protect ourselves from omicron?

“Continue with all the currently recommended practices: get vaccinated and complete the COVID-19 vaccination series if you haven’t yet done so, get a booster dose if you are eligible for one (all adults 6 months after the last mRNA vaccine or 2 months after the Johnson & Johnson vaccine), wear a mask when in public indoor settings, practice social distancing and limit the number of people at a gathering, practice good hand hygiene, get tested if you are ill or have been exposed to someone with COVID-19, and stay home (isolate yourself) if you test positive for COVID-19 (and contact your physician to arrange for monitoring and to be considered for treatment). Also, remember that influenza is now circulating in our community, so please also get your flu vaccination if you haven’t yet!”
Last reviewed: 
December 2021

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