Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
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.
UPDATE
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.
UPDATE
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

Reinfection with COVID-19

Reinfection with COVID-19
Updated Aug. 6, 2021

Cases of reinfection with COVID-19 have been reported, but remain rare​.​

In general, reinfection means a person was infected (got sick) once, recovered, and then later became infected again. Based on what we know from similar viruses, some reinfections are expected. We are still learning more about COVID-19. Ongoing COVID-19 studies will help us understand:

  • How likely is reinfection
  • How often reinfection occurs
  • How soon after the first infection can reinfection take place
  • How severe are cases of reinfection
  • Who might be at higher risk for reinfection
  • What reinfection means for a person’s immunity
  • If a person is able to spread COVID-19 to other people when reinfected
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About Variants

Viruses are constantly changing, including the virus that causes COVID-19. These changes occur over time and can lead to the emergence of variants that may have new characteristics. Vaccines continue to reduce a person’s risk of contracting the virus that cause COVID-19. Vaccines are highly effective against severe illness.

What CDC is doing

CDC is actively working to learn more about reinfection to inform public health action. CDC developed recommendations for public health professionals to help decide when and how to test someone for suspected reinfection. CDC has also provided information for state and local health departments to help investigate suspected cases of reinfection. We will update this guidance as we learn more about reinfection.

Important Ways to Slow the Spread of COVID-19