New Information: What We Know about Omicron and Other COVID-19 Variants

Microbiologist Esther Babady in her lab

Esther Babady is Director of MSK’s Clinical Microbiology Service.

You may have heard about a new variant of COVID-19 called Omicron. There are many questions about Omicron, and scientists will have more answers in the coming weeks.

Esther Babady, Director of MSK’s Clinical Microbiology Service, is a nationally recognized leader in understanding variants and testing for the virus that causes COVID-19.

Here, Dr. Babady answers questions you may have now about Omicron and how to protect yourself.

What is the Omicron variant of COVID-19?

The Omicron variant is a new strain of COVID-19 that was first identified in South Africa. When scientists find variants, it means the virus is changing as it moves from person to person throughout the population. It is completely normal and expected.

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Is the Omicron variant more contagious? Does it cause more severe disease?

We don’t know yet. We do know that Omicron has a high number of mutations, and many scientists say this could make it easier to spread. Scientists are studying if current vaccines and treatments will work against Omicron, and if Omicron causes more severe disease. There is much to be learned.

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Should I be worried about the Omicron variant?

The Omicron variant of COVID-19 is labeled by the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) as a “variant of concern.” The CDC says a variant of concern could have several possible attributes, including any or all of the following:

  • increased transmissibility
  • increased disease severity
  • decreased vaccine protection

Delta, which spread widely in the US in the summer of 2021, is another variant of concern. It’s important to understand that the vaccines continued to offer strong protection against Delta. Read more about how the CDC defines a variant of concern »

The variant was first seen in South Africa, and several countries have since reported cases.

On December 1, 2021, the CDC stated that the US had its first confirmed case of the Omicron variant. The person — a traveler who returned to California from South Africa on November 22 — was fully vaccinated, had mild symptoms that are improving, and is self-quarantining. The individual’s close contacts have tested negative.

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Will the current vaccines protect against the Omicron variant?

Manufacturers of all three vaccines are currently testing to see how well they work against the Omicron variant, and they are preparing to reformulate them if necessary.

Experts in the scientific community believe that current vaccines will provide at least some protection from severe illness caused by the Omicron variant. The beauty of the mRNA vaccines (made by Moderna and Pfizer-BioNTech) is that they can be quickly adjusted and improved. If we find out the current vaccines don’t provide adequate immunity from the Omicron variant, a new and improved vaccine could be made in a couple of months.

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What can I do now to protect myself from Omicron and other variants?

The most important thing you can do is get vaccinated against COVID-19 and get your booster shot. Young children and adolescents are eligible to receive the Pfizer-BioNTech vaccine. On November 19, 2021, the CDC expanded eligibility for booster shots to all adults over age 18. Getting your initial vaccination and following up with a booster shot can protect against severe illness and can stop the virus from spreading easily. Read more about when you should get a booster dose »

In addition to being vaccinated, you should wear a mask in some situations, stay home when you are sick, and wash your hands frequently. We know that these actions slow the spread of COVID-19, as well as other sicknesses like the cold and flu.


December 1, 2021

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