What are the effective methods of decontaminating N95 mask for reuse?
Based on laboratory-based studies, ultraviolet germicidal irradiation (UVGI), microwave generated steam, warm moist heat, and hydrogen peroxide vapor (HPV) were able to reduce the load of influenza viruses (A/H5N1, H1N1) or G. stearothermophilus and at the same time maintain the integrity of N95 respirators.
• Considering the current pandemic, there is a potential for shortage of N95 facepiece filtering respirator (FFR) for healthcare workers.
• No studies in humans were found comparing effectiveness of N95 post-decontamination.
• Laboratory based studies done on influenza virus (A/H5N1, H1N1) have shown that ultraviolet germicidal irradiation, microwave generated steam, or warm moist heat was able to reduce the viral load by as much as 4 log and at the same time maintain respirator performance by keeping the percent penetration below 5% and the pressure drop within standards.
• While UVGI was able to maintain integrity of FFRs up to 3 cycles, microwave generated steam may melt the metallic components of certain N95 masks.
• Hydrogen peroxide vapor (HPV) had minimal effect on respirator performance and structural integrity up to 20 cycles and was also effective in eradicating G. stearothermophilus and aerosolized bacteriophages.
• Bleach, ethanol and isopropanol all affected the mean penetration of the mask beyond the 5% limit.
• The Centers for Disease Control (CDC) does not recommend decontamination then reuse of FFRs as standard care but decontamination with UVGI, HPV or moist heat may be considered as an option in FFR shortages.