Omicron variant: what you need to know

Omicron in the United States

The CDC is working with state and local public health officials to monitor the spread of the Omicron variant of SARS-CoV-2, the virus that causes COVID-19. Omicron continues to be the dominant variant in the United States.

What we know about Omicron

The CDC has worked with global public health and industry partners to learn more about Omicron as we continue to follow its evolution. We continue to assess how easily it spreads, the severity of the disease it causes, and the effectiveness of available vaccines and drugs against it.


The Omicron variant, like other variants of SARS-CoV-2, is composed of a number of lineages and sublineages. The three most common lines of Omicron are currently BA.2, BA.4 and BA.5.

The Omicron variant spreads more easily than earlier variants of the virus that cause COVID-19, including the Delta variant. The CDC expects that anyone infected with Omicron, regardless of their vaccination status or whether or not they have symptoms, can transmit the virus to others. Data suggests that Omicron can re-infect individuals, even if they have recently recovered from COVID-19.


People infected with the Omicron variant may experience symptoms similar to the previous variants. The presence and severity of symptoms may be affected by COVID-19 vaccination status, presence of other health conditions, age, and history of infection. You should get tested immediately if you have symptoms of COVID-19, even if you are up to date on your vaccinations or have recently recovered from COVID-19.

Serious illness

Infection with Omicron usually causes less severe disease than infection with earlier variants. The data suggests that Omicron may cause milder disease, although some people may still have severe disease, require hospitalization, and die from infection with this variant. Although only a small percentage of people infected with Omicron require hospitalization, a large number of cases in a community could stress and potentially overwhelm a healthcare system, which is why it is important to take steps to protect yourself.


Vaccines against COVID-19 remain the best public health measure to protect people against COVID-19. This includes primary sets, booster shots and additional doses for those who need them.

Current vaccines protect against serious illness, hospitalizations and death due to infection with the Omicron variant. However, breakthroughs of infection in vaccinated people do occur. People who are up to date with their COVID-19 vaccines and get COVID-19 are less likely to develop serious illness than those who are not up to date on their vaccines and get COVID-19.


Scientists are working to determine how well existing antibody treatments fight COVID-19. Some monoclonal antibody treatments are less effective against certain lineages. Other non-monoclonal antibody treatments remain effective against Omicron. Public health agencies work with healthcare providers to ensure that effective treatments are used appropriately to treat patients.

We have the tools to fight Omicron


  • The CDC recommends COVID-19 primary series vaccines for anyone 6 months and older, and COVID-19 boosters for anyone 5 years and older, if eligible.

To find COVID-19 vaccination centers near you: Search, text your zip code to 438829, or call 1-800-232-0233.


  • In general, people do not need to wear a mask when outdoors.
  • If you are sick and need to be around others or caring for someone with COVID-19, wear a mask.
  • If the COVID-19 community level where you live is
    • Down
      • Wear a mask according to your personal preference, depending on your personal risk level.
    • Medium
      • If you’re at risk for serious illness, talk to your healthcare provider about wearing masks indoors in public.
      • If you live or will be congregating with someone at risk of serious illness, wear a mask when you are indoors with them.
    • High
      • If you are 2 or older, wear a properly fitted mask indoors in public, regardless of immunization status or individual risk (including in K-12 schools and other community settings).
  • If you are at risk of serious illness, wear a mask or respirator that gives you better protection.


  • Two types of tests are used to test for current infection: nucleic acid amplification tests (NAATs) and antigen tests. NAATs, such as PCR-based tests, are usually done in a laboratory, and antigen tests are usually done in a healthcare facility or at home. Both types of tests can tell you if you have a current infection.
  • The self-tests can be used at home or anywhere, are easy to use and produce quick results.
    • If your self-test gives a positive result, self-isolate and talk to your healthcare provider.
    • If you have any questions about your self-test result, call your healthcare provider or the public health department.

Individuals can use the CDC’s COVID-19 Viral Testing Tool to determine what type of test to look for.

Your test result will only tell you whether or not you have COVID-19. It will not tell you which variant caused your infection. Visit your state, tribal, local, or territorial health department website for the latest local testing information.

What the CDC is doing to learn more about Omicron

Characteristics of viruses

CDC scientists are working with partners to analyze data and virus samples that may answer important questions about the Omicron variant. The CDC will provide updates as new information becomes available.

Variant monitoring

In the United States, the CDC uses viral genomic surveillance to rapidly identify and track SARS-CoV-2 variants, and act on those findings to better protect public health. The CDC has established several ways to connect and share viral genomic sequence data produced by the CDC, public health laboratories, and commercial diagnostic laboratories in publicly accessible databases maintained by the National Center for Biotechnology Information

Add Comment