KN95 respirators vs. N95 respirators
Due to the shortage of N95 respirators for healthcare workers and first responders, the Center for Disease Control (CDC) has authorized the use of KN95 masks in place of N95 masks for the response to COVID19. A N95 and KN95 respirator are filtering facepiece respirator. A filtering facepiece respirator is a negative pressure particulate respirator with the filter as an integral part of the facepiece or with the entire facepiece composed of the filtering medium. N95 means the mask has been rated to filter at least 95 percent of airborne particles it encounters down to a 0.3 micron particle. The difference between an N95 and a KN95 mask is where the mask is certified. The KN95 respirator is manufactured and certified in China while the N95 is certified in the US by the National Institute for Occupational Safety and Health (NIOSH).
To help address concerns about availability during the COVID-19 pandemic, the FDA has issued Emergency Use Authorizations (EUAs) for certain personal protective equipment products including face shields, other barriers, and respiratory protective devices. In April, 2020, the FDA issued an umbrella Emergency Use Authorization – Appendix A approving the use of certain filtering face-piece respirators (FFRs) that are manufactured in China and are not approved by NIOSH. Other countries approve respirators according to country-specific standards. On May 7, 2020, the FDA reissued the April 3, 2020 EUA removing numerous respirators that failed to demonstrate a minimum particulate filtration efficiency of 95 percent in testing conducted at NIOSH. Effective October 15, 2020 the EUA no longer includes the eligibility criteria that were included in the previous June 6, 2020 authorization letter, meaning FDA will no longer be reviewing requests and adding new respirator models to Appendix A based on those criteria. FDA has determined based on the available information that KN95 respirator models may be effective in preventing exposure to pathogenic biological airborne particulates during respirator shortages resulting from the COVID-19 emergency.
The Greater Boston Pandemic Fabrication Team (Harvard-MIT Center for Regulatory Science) evaluated KN95 respirators in July 2020 and concluded that many of the masks do not provide levels of fit and filtration similar to those of N95 masks and are not acceptable for use in healthcare settings. Researchers at ECRI, a not-for-profit organization for healthcare safety, found that 60-70% of imported KN95 masks do not filter 95 percent of aerosol particulates. The group issued a hazard warning in September, 2020 that “hospitals and staff who treat suspected COVID-19 patients should be aware that imported masks may not meet current U.S. regulatory standards despite marketing that says otherwise” and that KN95 filtering facepiece respirators should not be used in high risk areas when treating patients with known or suspect COVID-19 infections. Like many non-certified masks, KN95 have ear loops, not head and neck straps. NIOSH-certified respirators require head and neck straps.
A spokesperson at the National Protective Technology Laboratory indicated that non-NIOSH certified respirators should only be used in a crisis situation. In the October 15 statement, the FDA concluded that authorization on KN95 respirators is limited to the respirator models in Appendix A for use in healthcare settings pursuant to CDC’s recommendations to prevent exposure to pathogenic biological airborne particulates during respirator shortages resulting from the COVID-19 outbreak. ECRI stated that, “KN95 masks that don’t meet U.S. regulatory standards still generally provide more respiratory protection than surgical or cloth masks and can be used in certain clinical settings.”