Investigation of three different UV-C irradiation schemes for bacterial decontamination of FFP2 masks to make them reusable.

The effect of FFP2 masks for infection prevention is essential in healthcare systems, however, depending on supply chains. Efficient methods to reprocess FFP2 masks may be needed in disasters. Therefore, different UV-C irradiation schemes for bacterial decontamination of used FFP2 masks were investigated.78 masks were irradiated with UV-light for durations between three and 120 seconds and subsequently analysed for the presence of viable bacteria on the inside. 10 masks served as control group. Irradiation on the inside of the masks reduced bacteria in proportion to the dose, with an almost complete decontamination after 30 seconds. Outside irradiation reduced the quantity of colonies without time dependent effects. Both side irradiation for cumulated 30 seconds or more showed almost complete decontamination.Overall, this study suggests that standardized UV irradiation schemes with treatment to both sides might be an efficient and effective method for FFP2 mask decontamination in times of insufficient supplies.