On July 27 in response to rising COVID-19 case counts caused by the Delta variant, the Centers for Disease Control and Prevention updated its guidance for individuals who have been fully vaccinated to recommend that they wear a mask indoors in public if they are in an area of substantial or high transmission of COVID-19. Currently, a large percentage of the United States, especially in the Southeast, is categorized as experiencing either substantial or high transmission. The CDC reasons that such additional measures are necessary in order to reduce the risk of being infected with the Delta variant and possibly spreading it to others.

The CDC guidance is not legally binding. However, many municipalities and local governments, such as Los Angeles County and the City of St. Louis, Missouri, have similarly responded to this new wave of infection by reinstituting mask mandates. Employers who are not located in states and localities that have reinstituted mask mandates are free to implement their own policies. Prudent employers should consider their own vaccination rates, current levels of infection, and other mitigation strategies as they decide whether it may be appropriate to temporarily reinstitute masking in the workplace.