Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

What You Need to Know About Variants

About Variants
Omicron Spread

CDC is monitoring the current surge of COVID-19 cases. Learn more about the Omicron variant and its expected impact on hospitalizations.

Omicron VariantHospitalization Forecast

What You Need to Know

Variants Are Expected

Viruses constantly change through mutation and sometimes these mutations result in a new variant of the virus. Some variants emerge and disappear while others persist. New variants will continue to emerge. CDC and other public health organizations monitor all variants of the virus that causes COVID-19 in the United States and globally.

Scientists monitor all variants but may classify certain ones as variants being monitored, variants of interest, variants of concern and variants of high consequence. Some variants spread more easily and quickly than other variants, which may lead to more cases of COVID-19. Even if a variant causes less severe disease in general, an increase in the overall number of cases could cause an increase in hospitalizations, put more strain on healthcare resources and potentially lead to more deaths.

Variants of Concern

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Omicron - B.1.1.529, BA.1, BA.1.1, BA.2, BA.3, BA.4 and BA.5

First identified: South Africa

Spread: Spreads more easily than other variants. CDC is working with state and local public health officials to monitor the spread of Omicron.

Symptoms:  Please refer to Symptoms of COVID-19 | CDC

Severe illness and death: Data suggest that Omicron is less severe in general. However, a surge in cases may lead to significant increases in hospitalization and death. More data are needed to fully understand the severity of illness and death associated with this variant.

Vaccine: Breakthrough infections in people who are vaccinated are expected, but being up to date on recommended vaccines is effective at preventing severe illness, hospitalizations, and death. The emergence of the Omicron variant further emphasizes the importance of vaccination and boosters.

Treatments: Some, but not all, 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.

Learn more about the Omicron variant

We Have the Tools to Fight COVID-19

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  • Vaccines reduce the risk of severe illness, hospitalization, and death from COVID-19.
  • People who are up to date on vaccines, including booster doses when eligible are likely to have stronger protection against COVID-19 variants, including Omicron. CDC recommends everyone eligible get vaccinated and a booster shot.
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When to wear a mask
  • Wear a well-fitting mask with the best fit, protection, and comfort for you.
  • If you are in an area with a high COVID-19 Community Level and are ages 2 or older, wear a well-fitting mask indoors in public.
  • If you are sick and need to be around others, or are caring for someone who has COVID-19, wear a mask.
  • If you are at increased risk for severe illness, or live with or spend time with someone at higher risk, speak to your healthcare provider about wearing a mask at medium COVID-19 Community Levels.
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  • Tests for COVID-19 tell you if you have an infection at the time of the test. This type of test is called a “viral” test because it looks for viral infection. Antigen or Nucleic Acid Amplification Tests (NAATs) are viral tests.
    • Additional tests would be needed to determine which variant caused your infection, but these typically are not authorized for public use.
  • As new variants emerge, scientists will continue to evaluate how well tests detect current infection.
  • Self-tests may be used if you have COVID-19 symptoms or have been exposed or potentially exposed to an individual with COVID-19.
    • Even if you don’t have symptoms and have not been exposed to an individual with COVID-19, using a self-test before gathering indoors with others can give you information about the risk of spreading the virus that causes COVID-19.