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What are variants, like Delta and Omicron?

Variants are normal. All viruses mutate and change in order to create stronger, more harmful versions of themselves. This is called a variant.

Scientists around the world are studying a new variant of COVID-19 called the Omicron variant, just as they did with Delta. Here’s what we know about Omicron as of Dec. 3, 2021:

  • Contagiousness: The Omicron variant appears to be more contagious than the Delta variant, but we do not yet know how much more.

  • Disease severity: No unusual symptoms have been reported following Omicron infection, though it is still too early to determine if the variant causes more severe disease.

  • Vaccine effectiveness: It is unknown at this time how effective our current vaccines will be against severe infection caused by Omicron. This is being studied by scientists worldwide. If needed, Moderna and Pfizer can update their vaccines to improve protection against infection caused by Omicron.

  • Treatment: It is unknown at this time how effective treatments will be against infection caused by Omicron.

Vaccines and boosters – as well as wearing masks when around others, keeping 6 feet apart, and washing hands often – remain our best protection against COVID-19 infection and spread, including most variants.