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.
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.

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
Delta Variant

The Delta variant causes more infections and spreads faster than earlier forms of the virus that causes COVID-19. It might cause more severe illness than previous strains in unvaccinated people.

  • Vaccines continue to reduce a person’s risk of contracting the virus that cause COVID-19, including this variant.
  • Vaccines continue to be highly effective at preventing hospitalization and death, including against this variant.
  • Fully vaccinated people with breakthrough infections from this variant appear to be infectious for a shorter period.
  • Get vaccinated and wear masks indoors in public spaces to reduce the spread of this variant.

About the Delta VariantVariants in the US

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