Reusability of Facemasks During an Influenza Pandemic
Institute of Medicine
Board on Health Sciences Policy
Telephone News Conference
April 27, 2006
John C. Bailar III, M.D, Ph.D.
The University of Chicago, Chicago
Donald S. Burke, M.D.
Professor of International Health and Epidemiology
Bloomberg School of Public Health, Johns Hopkins University, Baltimore
Co-chairs, Committee on the Development of Reusable Facemasks
For Use During an Influenza Pandemic
Good morning. I'm John Bailar. Before we take your questions, I and my colleague Donald Burke will provide a short overview of the study and our report's recommendations.
This report is the result of a three-month-long study addressing questions posed by the U.S. Department of Health and Human Services, namely, whether disposable medical masks and N95 respirators that were made to be used once could be reused in the event of a flu pandemic, and what steps would be needed to develop a reusable mask for the general public. Face coverings are one of several strategies that could be deployed in the event of an outbreak to help control the spread of influenza. The question of reusability arises from predictions that inexpensive, disposable masks likely would be in short supply if a pandemic develops in the near future.
During the course of our study, the committee heard from many experts, including public health researchers, influenza experts, representatives of medical mask and respirator manufacturers, and government officials, among others. In addition, we reviewed the available scientific literature on the uses of medical masks and respirators and what is known about their effectiveness against various contaminants. We also considered information on the use of face coverings during the SARS outbreak of 2003. Finally, we heard from materials scientists and experts in the manufacturing of polymers and other components of facemasks.
The committee was not asked to assess the effectiveness of various forms of face covering against the flu. And, in fact, no form of face covering has been tested for its effectiveness against influenza viruses specifically. However, the committee's approach to the question of reusability was shaped by several well-supported ideas. Some refer to flu generally and some to the first use of a face covering.
· First, of the forms of respiratory protection the committee was asked to consider, properly fitted N95 filtering facepiece respirators are likely to provide the best protection against influenza to the extent that it may be spread via an airborne route.
· A closely fitting, high-efficiency medical mask is likely to provide adequate protection against viruses borne in droplets projected through coughing and sneezing.
· A facemask that combines traits of both a medical mask and an N95 filtering facepiece will provide protection against both droplets and aerosols.
· Medical masks are likely to provide far less protection against aerosols than filtering facepiece respirators, but may offer better protection than woven masks, homemade alternatives, or no protection at all.
· No device is fail-safe, and its effectiveness depends on fit, level of exposures, and appropriate use.
· None of these devices protects against transmission of flu spread through direct contact, and hand washing is necessary when using and after removing these devices.
After considering all the testimony and other information we received, the committee concluded that there is currently no simple, reliable way to decontaminate these devices and enable people to use them safely more than once. There is relatively little data available about how effective these devices are against flu even the first time they are used. To the extent they can help at all, they must be used correctly, and the best respirator or mask will do little to protect a person who uses it incorrectly. Substantial research must be done to increase our understanding of how flu spreads, to develop better masks and respirators, and to make it easier to decontaminate them. Finally, the use of face coverings is only one of many strategies that will be needed to slow or halt a pandemic, and people should not engage in activities that would increase their risk of exposure to flu just because they have a mask or respirator.
Donald Burke will now provide some more detailed information on our specific findings about each of the different kinds of face covering and on our recommendations.
Thank you, John.
Any method of decontaminating a disposable N95 filtering facepiece respirator or medical mask must remove the viral threat, be harmless to the user, and not compromise the integrity of the various parts of the device. The committee found no method of decontamination that met all three criteria.
Also, there is no simple way to modify the manufacturing process or to dispense with fit-testing that would permit disposable N95 respirators to be reused.
Many versions of reusable respirators – also called elastomeric respirators – have facepieces that can be cleaned and reused. Although they are more expensive than the disposable N95 filtering facepieces, they could be considered as an alternative.
Protecting a disposable N95 respirator from contamination could allow for limited reuse. If an individual needs to reuse his or her own disposable N95 respirator, the committee recommends that it be done by:
· Placing a medical mask or a washable faceshield over the respirator to protect it from external surface contamination when there is a high risk of exposure to influenza.
· Using and storing the respirator in such a way that the physical integrity and efficacy of the respirator will not be compromised.
· Thoroughly washing up before and after removal of both the respirator and the device used to shield it and, if necessary and possible, appropriately disinfect the object used as a shield.
A respirator should not be reused if it is damaged or dirty, if it becomes too difficult to breathe while wearing the device, or if it does not pass a user seal check.
Washable, woven cloth masks have been used in hospitals in some countries. Also, in the absence of any alternative, some members of the public may improvise respiratory protection out of t-shirts, scarves, or other cloth. Given the lack of sufficient data either supporting or refuting the effectiveness of woven cloth masks and improvised coverings in blocking influenza transmission, the committee hesitates to discourage their use, but cautions that they are not likely to be as protective as medical masks or respirators. We are concerned that their use may give users a false sense of protection that could encourage risk-taking.
As noted earlier, considerable research needs to be done to address the use and reuse of face coverings. We call on the U.S. Department of Health and Human Services to expand pandemic influenza research to determine and characterize the exact routes of flu virus transmission and the risks associated with each. The department also should sponsor or conduct research on the effectiveness of simple decontamination techniques, such as bleach and ultraviolet light, and sponsor or conduct research on alternative filtering materials such as bioactive filters. Companies that make respirators and masks should consider modifications to processing conditions, chemicals, and finishes in order to improve the durability of filters. Finally, research is needed to develop appropriate public education and communication strategies to increase rates of proper usage and compliance by the public in the event of a pandemic.
That concludes our opening remarks. We will be glad to take your questions now. We would appreciate it if you would identify yourself by name and affiliation before asking your questions.