Where the CDC recommends masking up

The Centers for Disease Control and Prevention recommends that fully vaccinated people wear masks indoors in places where the virus is spreading, based on their "level of community transmission."

Specifically, the updated guidance applies to places that the CDC categorizes as having "high" and "substantial" transmission rates, as measured by a combination of case count and positivity rate thresholds.

Note: The CDC classifies transmission levels based on the following criteria:
■ High: At least 100 new cases per 100K residents over past week or 10%+ positivity rate
■ Substantial: 50-100 cases per 100K, 8-10% positivity rate
■ Moderate: 10-50 cases per 100K, 5-8% positivity rate
■ Low: 0-10 cases per 100K, 0-5% positivity rate Source: Centers for Disease Control and Prevention. As of August 11, 2021.