Ultraviolet Germicidal Irradiation on the New Silicone Half-Piece Elastometric Respirators
Condition: Covid19
MeSH terms: COVID-19
Study type: Interventional

Summary: 
      Since the innovation of our new half- elastometric half-piece respirator, this type of FFR
      has been used widely in our country. Decontamination methods including ultraviolet C (UVC)
      germicidal irradiation and 70% alcohol have been implemented to decontaminate the respirator.
      We than examined inactivation potential for the Porcine epidemic diarrhea virus (PEDV),
      numerous bacterial strains ,mostly skin-derived after the decontamination process.To enable
      rigorous integrity after repeated decontamination process, fit test by the Bitrex test
      ,tensile strength and elongation at break were also evaluated. Our results showed that the
      UVC at the dose of 3 J/cm2 can eradicate the bacteria at 60 min and virus at 10 min.No fungus
      was found on the mask surface at the beginning. Good Fit test , tensile strength and
      elongation at break were still main maintained after multiple cycles of decontamination. No
      evidence of physical degradation by gross visual inspection was found. 70% alcohol is also an
      easy and effective way to eradicate microorganisms on the mask.As the current pandemic is
      expected to continue for months to years, the need to supply adequate reserves of PPE and
      develop effective reprocessing is crucial. Our studies demonstrated that the novel silicone
      mask can be safely reprocessed and decontaminated for many cycles by UVC irradiation and help
      restore the shortage of the important protective devices in the COVID-19 pandemic era.
    

Detailed description: 
      this study showed that UVC irradiation at the dosage 300 uWatt-sec/cm2 for 1 minute
      satisfactorily decontaminated the silicone mask as measured by viral culture. The timing to
      eradicate bacteria was 60 minutes longer due to the tolerability of the bacteria .70% alcohol
      effectively decontaminate the virus and bacteria deposited on the masks and filters. Good
      level of fit can be maintained following UVC treatment. The tensile strength of the strap was
      retained over multiple decontamination cycles using UVC and dry heat upto 60 cycles.Given the
      efficacy of the disinfection by UVC and 70 % alcohol ,these types of decontamination method
      could potentially be used for the new type of silicone masks half-piece respirator in the
      setting of a crisis with inadequate supplies of PPE.
    

Intervention name(s): UVC Irradiation; UVC Irradiation; Fit test; Tensile strength
Intervention type(s): Device; Drug; Device; Device
Intervention description(s): We used the Porcine epidemic diarrhea virus (PEDV) as the indicator virus .An N99 mask was contaminated by spraying or applying with the virus on the exterior and interior surface of each silicone mask. Also, 100 μl of the viral suspension was spotted onto the filter part of N99 masks. Following 20-30 minutes of drying, the silicone masks underwent each of the decontamination procedures which are ultraviolet-C (UV-C) irradiation and 70% alcohol treatment. For UV irradiation, N99 masks were placed in an UV-C incubator ) and were exposed for different times at 1, 10 and 20 minutes, respectively.Untreated control and treated N99 masks were analyzed for viral infectivity in VERO cell cultures. At 48 hours post-infection, cells were examined for evaluation the viral infectivity via observation of cytopathic effect. Results for each treatment express mean ± standard deviations of 3 biological replicates.; Bacterial and fungal sampling were obtained from the inside and outside surface areas likely to the frequently touched and close contact with the face of hospital personnel. The cultures were then isolated onto the blood agars and Mac Conkey agars, respectively. After incubation, the total number of bacterial and fungal colonies were counted, recorded, and selected different colonies.; All the participants had to pass the initial fit test.After decontamination with UVC irradiation for 60 minutes, fit testing was conducted using qualitative fit test (Bittrex Solution aerosol),; We measured the tensile strength of the strap of the Silicone mask before and after the UVC irradiation to study the strength and reliliency of the strap
Intervention model: Sequential Assignment
Intervention model description: Before and after intervention in one group
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: COVID-19; Decontamination; Filtering facepiece respirators; UVC