Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
To maximize protection from the Delta variant and prevent possibly spreading it to others, get vaccinated as soon as you can and wear a mask indoors in public if you are in an area of substantial or high transmission.
UPDATE
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.

What You Need to Know about Variants

What You Need to Know about Variants
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About the Delta Variant: Vaccines continue to reduce a person’s risk of contracting the virus that cause COVID-19, including this variant. Vaccines are highly effective against severe illness, but the Delta variant causes more infections and spreads faster than earlier forms of the virus that causes COVID-19.

The virus that causes COVID-19 is constantly changing, and new variants of the virus are expected to occur. Sometimes new variants emerge and disappear. Other times, new variants persist. Numerous variants of the virus that causes COVID-19 are being tracked in the United States and globally during this pandemic.

Top Things You Need to Know

  1. Variants are expected. The best way to slow the emergence of new variants is to reduce the spread of infection by taking measures to protect yourself including getting a COVID-19 vaccine when available.
  2. Vaccines keep you from getting sick, being hospitalized, or dying from COVID-19.
  3. All COVID-19 tests can detect all variants, but they will not tell you which variant you have.
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Vaccines 

  • FDA-approved or authorized a COVID-19 vaccines protect against Delta and other known variants.
  • These vaccines are effective at keeping people from getting COVID-19, getting very sick, and dying.
  • We don’t yet know how effective the vaccines will be against new variants that may arise.
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Symptoms 

  • Most variants cause similar COVID-19 symptoms.
  • Some variants may cause more people to get sicker and die, for example, Alpha and Delta variants.
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Masks 

  • Wearing a mask is one way to reduce the spread of Delta and other variants.
  • People who are not fully vaccinated should wear a mask indoors in public at all levels of community transmission.
  • CDC recommends that people who are fully vaccinated should wear a mask indoors in areas of substantial or high transmission.
  • Wearing a mask is most important if you have a weakened immune system or if, because of your age or an underlying medical condition, you are at increased risk for severe disease, or if someone in your household has a weakened immune system, is at increased risk for severe disease, or is unvaccinated. If this applies to you or your household, you might choose to wear a mask regardless of the level of transmission in your area.
  • If you have a condition or are taking medications that weaken your immune system, you may not be fully protected even if you are fully vaccinated. You should continue to take all precautions recommended for unvaccinated people until advised otherwise by your healthcare provider.
  • People who are NOT vaccinated, should continue to take steps to protect themselves.
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Testing 

  • All tests work for all variants, but they will not tell you which variant you have.
  • As new variants emerge, scientists will continue to evaluate how well tests work.

Types of Variants

Scientists monitor all variants but may classify certain ones as variants of interest, concern, or high consequence based on how easily they spread, how severe their symptoms are, and how they are treated.

Some variants seem to spread more easily and quickly than other variants, which may lead to more cases of COVID-19. An increase in the number of cases will put more strain on healthcare resources, lead to more hospitalizations, and potentially more deaths.

Variants of Concern in the US

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Alpha - B.1.1.7

First identified: United Kingdom

Spread: Much faster than other variants

Severe illness and death: May potentially cause more people to get sicker and to die

Vaccine: Currently FDA approved or authorized vaccines do work against this variant. Some breakthrough infections in fully vaccinated people are expected but remain rare. All vaccines are particularly effective against severe illness, hospitalization, and death.

Treatments: Treatments are effective against this variant.

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Beta - B.1.351

First identified: South Africa

Spread: May spread faster than other variants

Severe illness and death: Current data do not indicate more severe illness or death than other variants

Vaccine: Currently FDA approved or authorized vaccines do work against this variant. Some breakthrough infections are expected but remain rare. All vaccines are particularly effective against severe illness, hospitalization and death.

Treatments: Certain monoclonal antibody treatments are less effective against this variant.

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Gamma - P.1

First identified: Japan/Brazil

Spread: Faster than other variants

Severe illness and death: Current data do not indicate more severe illness or death than other variants

Vaccine: Currently FDA approved or authorized vaccines do work against this variant. Some breakthrough infections are expected but remain rare. All vaccines are particularly effective against severe illness, hospitalization and death.

Treatments: Certain monoclonal antibody treatments are less effective against this variant.

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Delta - B.1.617.2

First identified: India

Spread: Much faster than other variants

Severe illness and death: May cause more severe cases than the other variants

Vaccine: Infections happen in only a small proportion of people who are fully vaccinated, even with the Delta variant. Some breakthrough infections are expected but remain rare. However, preliminary evidence suggests that fully vaccinated people who do become infected with the Delta variant can spread the virus to others. All vaccines are particularly effective against severe illness, hospitalization and death.

Treatments: Certain monoclonal antibody treatments are less effective against this variant.