Dear Students, Faculty and Staff,

Renewed discussions regarding the potential benefit of double masking on source control and prevention of COVID-19 transmission have prompted questions about whether changes will be made to the current University masking policy. Eleven months of experience has demonstrated that robust infection prevention protocols such as masking, maintaining physical distance, limiting gatherings, and washing hands regularly have been effective in limiting the transmission of COVID-19 on campus.

At this time, we are not aware of a well-designed study that has been conducted to scientifically answer the question, “are two masks better at preventing COVID-transmission than one?” One study demonstrates the impact of wearing a well-fitting mask to improve source control and how wearing an overlying mask may improve overall mask fit. Logically, having additional layers of barrier protection over the nose and mouth should reduce particle dispersion.

With variants of the virus that cause COVID-19 now circulating, many are looking for ways to augment the infection prevention strategies in place – double masking is one such strategy. In an effort to support this approach, Duke will make available disposable medical masks on campus for students, faculty, staff and visitors who want them. These masks can be obtained at any of the surveillance testing sites on campus.

As we strive to continuously update our COVID-19 guidance to keep in step with the scientific community, we have updated masking guidance language as follows. We will continue to closely monitor COVID-19 infections among Duke community members and, should we see any concerning trends or signals, will reevaluate our recommendations below:

  • Double masking is optional at this time. Duke students, faculty, staff, and visitors are still required to wear a mask in all outdoor public settings where social distancing measures cannot be maintained (even briefly), and at all times in shared spaces indoors. Should individuals choose to wear a second mask, they may place a Duke-issued medical mask over the top of their own mask. Wearing the Duke-issued medical mask as the outer layer provides a fluid-resistant barrier. Duke-issued medical masks will be available at any of the surveillance testing sites on campus.

In addition, the proper fit of a mask improves its effectiveness. Simple mask modifications can be made to help improve its fit, and thereby improve source control. There are many options to make your mask fit better if it is too loose.

  • This video demonstrates one way to make your mask tighter.
  • A second option is to simply twist the straps of your Duke-issued mask before you put it on so that the elastic is in a crisscross.
  • Another option is to use a plastic clip to pull the straps tighter behind your head.

More information about proper use of masks is available on the Centers for Disease Control (CDC) website.


Matthew Stiegel, Ph.D.
Director, Occupational and Environmental Safety Office

Becky Smith, MD,
Associate Professor of Medicine, Division of Infectious Diseases and International Health, Medical Director, Duke Infection Prevention and Hospital Epidemiology

Kyle Cavanaugh,
Vice President, Administration