COVID-19 variants

Updated January 3, 2022.

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COVID variant

Viruses constantly change through mutation. Sometimes these mutations result in a new variant of the virus. Sometimes new variants emerge and then disappear. Other times, new variants emerge and continue to spread. Scientists have documented multiple variants of the virus that causes COVID-19 around the world. Scientists are studying these variants to learn more and control their spread.

Centers for Disease Control (CDC) and the World Health Organization (WHO) classify some variants as variants of concern. CDC defines a variant of concern as one that may spread more easily, cause more severe disease, reduce the effectiveness of treatments or vaccines, or be harder to detect using current tests.

The CDPHE laboratory and some private laboratories routinely do genetic tests on thousands of COVID-19 samples from around the state each week. This allows CDPHE to track the variants that are circulating in Colorado. Variant data is available on CDPHE’s data dashboard.

Omicron variant

As of December 2021, the omicron variant is the main variant in Colorado. According to CDC, omicron likely spreads more easily than the original COVID-19 virus. Medical researchers are still learning more about omicron.Getting three doses of the COVID-19 vaccine is  the best way to protect yourself,  loved ones, and the community.

While early evidence does show that vaccines are likely less effective against omicron, they still reduce your chance of getting seriously sick or needing to be hospitalized due to COVID-19. Even with limited data, there is strong evidence that people who have gotten their third dose have much better protection than those who have received only two doses. Those who get a dose of Pfizer or Moderna after the Johnson & Johnson vaccine also showed increased immunity in laboratory studies.

CDPHE is watching closely for omicron cases using three main disease monitoring systems: a robust wastewater surveillance program, enhanced case investigation and contact tracing, and traveler monitoring. You can see how many omicron cases have been identified in Colorado on our COVID-19 data dashboard

Delta variant

Delta variant was first identified in India in December 2020. From June 2021 to December 2021, delta was the main variant in Colorado. It is much more contagious than previous variants. Many cases of COVID-19 in the U.S. are caused by delta variant.

The COVID-19 vaccine is effective against delta variant. While some vaccinated people can still become infected with delta and spread it to others, the vaccine works very well to prevent serious illness and hospitalization in people who do get breakthrough infections. Monoclonal antibody therapy also works well to help people infected with delta get better.

To learn more about variants, visit CDC’s webpage What You Need to Know About Variants.