Ultraviolet Germicidal Irradiation on the New Silicone Half-Piece Elastometric Respirators

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.

Conditions

• Covid19

Interventions

DEVICE

UVC Irradiation

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.

DRUG

UVC Irradiation

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.

DEVICE

Fit test

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),

DEVICE

Tensile strength

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

Sponsors & Collaborators

• Bangkok Metropolitan Administration Medical College and Vajira Hospital

  lead OTHER_GOV

Principal Investigators

• Thananda Trakarnvanich · Bangkok Metropolitan Administration and Vajira Hospital

Study Design

Allocation

NA

Purpose

PREVENTION

Masking

NONE

Model

SEQUENTIAL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-04-01

Primary Completion

2021-02-05

Completion

2021-02-05

Countries

• Thailand

Study Locations