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.


Updated July 12, 2021

CDC is reviewing this page to align with updated guidance.

Omicron Variant

Learn what you should know about Omicron and other COVID-19 variants.

About Variants
When to wear a mask
  • Wear a mask with the best fit, protection, and comfort for you.
  • Wear a well-fitting mask or respirator when the COVID-19 Community Level is high.
  • 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 high risk of getting very sick, wear a well-fitting mask or respirator when the COVID-19 Community Level is medium or high.
Have questions about getting or spreading COVID-19 after being vaccinated?

Learn more about COVID-19 vaccine myths and facts.