Table V.
Results of methods to recondition personal protective equipment
| Study | Virus | Disinfectant | Disinfection phase | Exposure time | Reduction of viral infectivity (log10) or (%) | Effect on material properties and functionality | |
|---|---|---|---|---|---|---|---|
| 1 | Blanchard et al. (2020) | IAV and RSV | Ozone (20 ppm) + 50–70% RH | Surgical facemasks (1 cm x 1 cm sample swatches) | 40 min | Equal to 70% ethanol inactivation | Material properties were preserved and filtration capacity of masks was maintained. |
| Tyvek (disposable gown) 1 cm x 1 cm | |||||||
| N95 respirators 1 cm x 1 cm | |||||||
| Bunny suits 1 cm x 1 cm | |||||||
| PAPR hoods 1 cm x 1 cm | |||||||
| 2 | Campos et al. (2020) | SARS-CoV-2 | Ambient humidity (60%) without BSA | Meltblown fabric from N95-grade FFRs | 60°C for 30 min | 2.16 ± 0.23 log10 | Temperatures of 75–85 °C are able to efficiently inactivate the virus in 20–30 min under 100% RH, without lowering filtration efficiency. Filtration efficacy started to decrease significantly after 10 cycles with temperature of 95°C probably due to the absorption of water or other mechanisms that can decay the electrostatic charge. |
| Ambient humidity (60%) without BSA | 75°C for 30 min | 3.69 ± 0.32 log10 | |||||
| Ambient humidity (60%) without BSA | 85°C for 20 min | >4.77 log10 | |||||
| Ambient humidity (60%) without BSA | 95°C for 5 min | >4.77 log10 | |||||
| Ambient humidity (60%) with BSA | 60°C for 30 min | 1.07 ± 0.06 log10 | |||||
| Ambient humidity (60%) with BSA | 75°C for 30 min | 2.89 ± 0.31 log10 | |||||
| Ambient humidity (60%) with BSA | 85°C for 20 min | 4.3 ± 0.55 log10 | |||||
| Ambient humidity (60%) with BSA | 95°C for 5 min | 4.8 ± 0.44 log10 | |||||
| 100% humidity without BSA | 60°C for 30 min | 2.82 ± 0.09 log10 | |||||
| 100% humidity without BSA | 75°C for 30 min | >4.97 log10 | |||||
| 100% humidity without BSA | 85°C for 20 min | >4.97 log10 | |||||
| 100% humidity without BSA | 95°C for 5 min | >4.97 log10 | |||||
| 100% humidity with BSA | 60°C for 30 min | 2.27 ± 0.09 log10 | |||||
| 100% humidity with BSA | 75°C for 30 min | 4.92 ± 0.12 log10 | |||||
| 100% humidity with BSA | 85°C for 20 min | >5.02 log10 | |||||
| 100% humidity with BSA | 95°C for 5 min | >5.02 log10 | |||||
| 3 | Choi et al. (2020) | SARS-CoV-2 | Moist heat generated by multi-cooker | FFRs 3M Model 1860 in simulated saliva | 65°C for 30 min | ∼1.5 log10 | All FFRs absorbed <1 g of water when in a paper bag. Collection efficacy exceeded 95% and inhalation resistance was preserved. After five cycles of moist heat treatment, 3M 8210 and NS 721 had no change in strap elasticity, while 3M 1860 and 3M 8511 showed a small change (<10%). |
| FFRs 3M Model 1860 in simulated lung fluid | ∼3.2 log10 | ||||||
| FFRs 3M Model 8511 in simulated saliva | ∼2.5 log10 | ||||||
| FFRs 3M Model 8511 in simulated lung fluid | ∼3.2 log10 | ||||||
| FFRs 3M Model 8210 in simulated saliva | ∼2.2 log10 | ||||||
| FFRs NS Model 7210 in simulated saliva | ∼2.2 log10 | ||||||
| 4 | Daeschler et al. (2020) | SARS-Cov-2 | 70°C + 50% RH | N95 respirators | 2–18 min | Reduced to undetectable levels | Masks maintained fibre diameters similar to untreated masks and continued to meet standards for fit, filtration efficiency and breathing resistance. |
| 5 | Gopal et al. (2020) | SARS-Cov-2 | Zinc oxide embedded into fabrics (only tested on PA66) | Cotton, polypropylene (PPP) fabrics and polyamide (PA66) | 60 min | 2 log | Cotton and polyamide 66 (PA66) can strongly trap viruses as only 56% of SARS-CoV-2 can be recovered from cotton samples and 92% from PA66 after viral inoculation. PPP is poor at trapping viruses. |
| 6 | Ibanez-Cervantes et al. (2020) | SARS-CoV-2 | Hydrogen peroxide plasma | N95 3M Model 8210 | 47 min | Undetectable by RT-PCR | Not tested |
| 7 | Ludwig-Begall et al. (2020) | PRCV | UV irradiation | Surgical mask coupons | 2 min | ∼5 log10 | Not tested |
| Vaporized H2O2 (59% liquid H2O2) 750 ppm | 28 min | ∼5 log10 | |||||
| Dry heat (102°C) | 60 min | ∼5.5 log10 | |||||
| UV irradiation | Surgical mask straps | 2 min | ∼2.9 log10 | ||||
| Vaporized H2O2 (59% liquid H2O2) 750 ppm | 28 min | Non-significant | |||||
| Dry heat (102°C) | 60 min | ∼1.2 log10 | |||||
| UV irradiation | FFR coupons | 4 min | ∼3.2 log10 | ||||
| Vaporized H2O2 (59% liquid H2O2) 750 ppm | 28 min | ∼4 log10 | |||||
| Dry heat (102°C) | 60 min | ∼2.5 log10 | |||||
| UV irradiation | FFR straps | 4 min | (-) | ||||
| Vaporized H2O2 (59% liquid H2O2) 750 ppm | 28 min | ∼1.2 log10 | |||||
| Dry heat (102°C) | 60 min | (-) | |||||
| 8 | Ma et al. (2020) | Avian infectious bronchitis virus | Steam | N95 FFR masks | 5 min | Undetectable by RT-PCR | Blocking efficacy of 99% verified in all masks except for one model that seemed to have thinner layers compared with other models. Therefore, masks with thinner layers can have reduced blocking efficacy. |
| 9 | Mantlo et al. (2020) | SARS-CoV-2 | Clyraguard copper iodine complex undiluted | Suspension test | 10 min | 2 log | Not tested |
| 30 min | Below limit of detection (<75 TCID50 per mL) | ||||||
| 60 min | Below limit of detection (<75 TCID50 per mL) | ||||||
| 10 | Ozog et al. (2020) | SARS-CoV-2 | UV-C irradiation (1.5 J/cm2 to each side) | N95 FFR models (3M 1860, 8210, 8511, 9211; Moldex 1511) | 60–70 s (for each side) | Below limit of detection (101.3 TCID50/4 mm punch) | Not tested |
| 11 | Perkins et al. (2020) | SARS-CoV-2 | Dry heat (60°C) | N95 respirator coupons + parchment paper | 60 min | All samples were positive analysed by microscopy for cytopathic effect | Not tested |
| Dry heat (70°C) | 60 min | All samples were positive analysed by microscopy for cytopathic effect | |||||
| Dry heat (75°C) | 60 min | All samples were positive analysed by microscopy for cytopathic effect | |||||
| Dry heat (60°C) | N95 respirator coupons + tissue culture | (-) | (-) | ||||
| Dry heat (70°C) | 60 min | All samples were positive analysed by microscopy for cytopathic effect | |||||
| Dry heat (75°C) | 60 min | All samples were positive analysed by microscopy for cytopathic effect | |||||
| Dry heat (60°C) | Intact N95 respirators | (-) | (-) | ||||
| Dry heat (70°C) | 60 min | All samples were positive analysed by microscopy for cytopathic effect | |||||
| Dry heat (75°C) | 60 min | Most samples were positive analysed by microscopy for cytopathic effect | |||||
| Ambient temperature | 5 days | 5/9 samples were positive analysed by microscopy for cytopathic effect | |||||
| 12 | Rathnasinghe et al. (2020) | SARS-CoV-2 | UV-C irradiation (5.43 mW/cm2) | N95 mask squares | 120 s per side | 3.5 log | Not tested |
| 13 | Rockey et al. (2020) | Bacteriophage MS2 | Temperature (72°C and 82°C) + PBS | N95 respirator coupons | 30 min | 0.24 log 10 (72°C + 1% RH), 0.19 log10 (82°C + 1% RH) | Not tested |
| 6.87 log 10 (72°C + 89% RH), 6,90 log10 (82°C + 89% RH) | |||||||
| Temperature (72°C and 82°C) + DMEM-A | 1.44 log 10 (72°C + 1% RH), 2.77 log10 (82°C + 1% RH) | ||||||
| 6.56 log 10 (72°C + 89% RH), 7.16 log10 (82°C + 89% RH) | |||||||
| Temperature (72°C and 82°C) + saliva | 0.99 log 10 (72°C + 13% RH), 0.88 log10 (82°C + 1% RH) | ||||||
| 1.45 log 10 (72°C + 25% RH), 1.74 log10 (82°C + 13% RH) | |||||||
| Temperature (72°C and 82°C) + (PBS + BSA) | 1.5 log 10 (72°C + 13% RH), 0.77 log10 (82°C + 1% RH) | ||||||
| 2.72 log 10 (72°C + 25% RH), 3.56 log10 (82°C + 13% RH) | |||||||
| Bacteriophage phi6 | Temperature (72°C and 82°C) + PBS | 0.99 log 10 (72°C + 1% RH), 1.48 log10 (82°C + 1% RH) | |||||
| 6.79 log 10 (72°C + 89% RH), 6,70 log10 (82°C + 89% RH) | |||||||
| Temperature (72°C and 82°C) + DMEM-A | 2.58 log 10 (72°C + 1% RH), 3.87 log10 (82°C + 1% RH) | ||||||
| 6.81 log 10 (72°C + 89% RH), 7.63 log10 (82°C + 89% RH) | |||||||
| Temperature (72°C and 82°C) + saliva | 0.95 log 10 (72°C + 13% RH), 1.09 log10 (82°C + 1% RH) | ||||||
| 1.69 log 10 (72°C + 25% RH), 2.62 log10 (82°C + 13% RH) | |||||||
| Temperature (72°C and 82°C) + (PBS + BSA) | 1.33 log 10 (72°C + 13% RH), 0.76 log10 (82°C + 1% RH) | ||||||
| 1.34 log 10 (72°C + 25% RH), 1.98 log10 (82°C + 13% RH) | |||||||
| MHV | Temperature (72°C and 82°C) + DMEM-A | 2.51 log 10 (72°C + 1% RH), 3.30 log10 (82°C + 1% RH) | |||||
| 4.19 log 10 (72°C + 89% RH), 4.38 log10 (82°C + 89% RH) | |||||||
| IAV | Temperature (72°C and 82°C) + DMEM-A | 1.25 log 10 (72°C + 1% RH), 2.71 log10 (82°C + 1% RH) | |||||
| 3.71 log 10 (72°C + 89% RH), 3.37 log10 (82°C + 89% RH) | |||||||
| 14 | Glasbrenner et al. (2021) | TGEV | UV (300–400 nm) simulated sunlight | FFR 3M 1860 | (-) | (-) | All FFRs maintained collection efficacy and breathing resistance after one and five cycles ((Model 3M 8210 not tested for five cycles). Reduced strap elasticity from NS 7210 model with 19% change in stress). |
| FFR 3M 8210 | (-) | (-) | |||||
| FFR 3M 8511 | (-) | Inactivation less efficient | |||||
| FFR NS 7210 | (-) | Inactivation below level of detection | |||||
| SARS-CoV-2 | FFR 3M 1860 + SS and LF | 20 min (13.3 J cm2) SS/40 min (26.5 J cm2) FL | Inactivation below level of detection | ||||
| FFR 3M 8210 + SS and LF | (-) | (-) | |||||
| FFR 3M 8511 + SS and LF | 60 min (37.8 J cm2) for SS and FL | Complete inactivation | |||||
| FFR NS 7210 + SS and LF | 20 min (13.3 J cm2) for SS and LF | Inactivation below level of detection | |||||
| 15 | Uppal et al. (2021) | HCoV-OC43 | Ozone (20 ppm) | N95 FFRs | 10 min | 98.1411% | Not tested |
| Ozone (25 ppm) | 10 min | 97.4138% | |||||
| 15 min | 99.9947% | ||||||
| 20 min | 99.9966% | ||||||
| Ozone (50 ppm) | 10 min | 99.9860% | |||||
| 15 min | 99.9956% | ||||||
| 20 min | 99.9925% | ||||||
| 16 | Valdez-Salas et al. (2021) | Enveloped H5N1 avian influenza virus | Formulated disinfectant - 0.2% benzalkonium chloride, 85% ethanol-water, 0.03% triclosan, 10% silver nanoparticles, 0.3% lauryl alcohol ethoxylate, 0.2% Triton X-100, 2% citric acid, microdacyn | Suspension test | 15 min | No presence of haemagglutinine - complete inactivation | Not tested |
IAV, avian influenza virus; RSV, respiratory syncytial virus; SARS-CoV-2, severe acute respiratory syndrome coronavirus-2; PRCV, porcine respiratory coronavirus; IBV, avian infectious bronchitis virus; MHV, mouse hepatitis coronavirus; PAPR, powered air purifying respirator; FFR, filtering facepiece respirator; RH, relative humidity; UV-C, ultraviolet C irradiation; PSB, phosphate-buffered saline; BSA, bovine serum albumin; DMEM, Dulbecco's modified Eagle medium; SS, simulated saliva; FF, lung fluid.