Transmission to health care workers (HCW) poses a major burden in the current Covod-19 pandemic. Unprotected exposure to a SARS-CoV-2p patient is a key risk factor for HCWs. Droplet transmission, and high transmission during aerosol-generating procedures are modes of transmission, requiring a respirator such as N95 or FFP2 respirator to protect the HCWs, likely the most important part of personal protection equipment (PPE). However, many HCW were infected due to lack of PPE, or failure to use them. The worldwide shortage of respirators triggered the development of reprocessing used N95 or FFP respirator. Our proposal with H2O2 plasma sterilization for decontamination allows to reprocess a type of FFP2 still meeting filtration effectiveness of EN 149, the European standard for new respirators. The protocol is simple, uses available resources in hospitals and can be rapidly implemented to decrease the shortage of respirators during this crisis. The goal of the study was the evaluate if respirators can be reprocessed without hampering filtration capacity outlined by EN 149
Used FFP2 respirators – Model 3M AuraTM 1862+ - were sterilized using a low temperature process Hydrogen peroxide (H2O2) V-PRO® maX Low Temperature, a FDA approved method to decontaminate FFP2 respirator. Decontaminated respirators were further checked for residual peroxide by a single-gas detector for H2O2. The Total Inward Leakage of the protective respirators was quantitatively tested with 10 test persons in an atmosphere charged with Paraffin aerosol according to EN 149. The fit factor was calculated as the inverse of the Total Inward Leakage.
Ten new and ten decontaminated FFP2 respirators were simultaneously tested for filtration effectiveness. None of the respirators exceeded peroxide maximum acceptable concentration of peroxide before use. More than 4000 respirators have been reprocessed so far, at cost of approximately 0.3 Euro/piece.
FFP 2 respirators can be safely reprocessed once after decontamination with plasma peroxid sterilization still meeting EN 149 requirements as new respirators. This allows to almost double the current number of FFP2 respirators that are in serious shortage.