Figure 1.

Recovery of virus after elution from inoculated, untreated surgical masks and filtering facepiece respirators (FFRs). Recovery of infectious porcine respiratory coronavirus from inoculated untreated surgical masks (SM) and FFRs was analysed in swine testicular cells. The cell culture limit of detection (LOD) was 0.8 log₁₀ TCID₅₀/mL (6.31 × 10⁰). Similar levels of virus recovery were detected for left, right and middle (L, R, M) coupons of masks and respirators; recovery efficacy of infectious virus from straps (S) deviated significantly in all analyses from the mean of all coupons and remained below the LOD for all assays performed on FFR straps. P-values were computed using a two-sided independent sample t-test to calculate differences between individual coupon values and differences between mean values of all coupons and straps, where ∗∗∗∗P<0.0001, ∗∗∗P<0.001, ∗∗P<0.01, ∗P<0.05, and ns is P≥0.05. UV, ultraviolet.