Am J Infect Control . Exploring inactivation of SARS-CoV-2, MERS-CoV, Ebola, Lassa, and Nipah viruses on N95 and KN95 respirator material using pho

[tetano]

Am J Infect Control


. 2022 Aug;50(8):863-870.
doi: 10.1016/j.ajic.2022.02.016.
Exploring inactivation of SARS-CoV-2, MERS-CoV, Ebola, Lassa, and Nipah viruses on N95 and KN95 respirator material using photoactivated methylene blue to enable reuse


Florine E M Scholte[SUP] 1 [/SUP], Kareem B Kabra[SUP] 2 [/SUP], Sarah R Tritsch[SUP] 2 [/SUP], Joel M Montgomery[SUP] 1 [/SUP], Christina F Spiropoulou[SUP] 1 [/SUP], Christopher N Mores[SUP] 2 [/SUP], Brian H Harcourt[SUP] 3 [/SUP]



Affiliations

• PMID: 35908824
• DOI: 10.1016/j.ajic.2022.02.016

Abstract

Background: The COVID-19 pandemic resulted in a worldwide shortage of N95 respirators, prompting the development of decontamination methods to enable limited reuse. Countries lacking reliable supply chains would also benefit from the ability to safely reuse PPE. Methylene blue (MB) is a light-activated dye with demonstrated antimicrobial activity used to sterilize blood plasma. Decontamination of respirators using photoactivated MB requires no specialized equipment, making it attractive for use in the field during outbreaks.
Methods: We examined decontamination of N95 and KN95 respirators using photoactivated MB and 3 variants of SARS-CoV-2, the virus that causes COVID-19; and 4 World Health Organization priority pathogens: Ebola virus, Middle East respiratory syndrome coronavirus, Nipah virus, and Lassa virus. Virus inactivation by pretreating respirator material was also tested.
Results: Photoactivated MB inactivated all tested viruses on respirator material, albeit with varying efficiency. Virus applied to respirator material pre-treated with MB was also inactivated, thus MB pretreatment may potentially protect respirator wearers from virus exposure in real-time.
Conclusions: These results demonstrate that photoactivated MB represents a cost-effective, rapid, and widely deployable method to decontaminate N95 respirators for reuse during supply shortages.

Keywords: COVID-19; Decontamination; Hemorrhagic fever virus; Methylene blue; N95 respirator; Photochemical inactivation.

 

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Am J Infect Control


. 2022 Aug;50(8):857-862.
doi: 10.1016/j.ajic.2022.03.003.
Methylene blue applied to N95 respirators and medical masks for SARS-CoV-2 decontamination: What is the likelihood of inhaling methylene blue?


Thomas S Lendvay[SUP] 1 [/SUP], Jinwei Xu[SUP] 2 [/SUP], James Chen[SUP] 3 [/SUP], Tanner Clark[SUP] 4 [/SUP], Yi Cui[SUP] 5 [/SUP]



Affiliations

• PMID: 35908823
• DOI: 10.1016/j.ajic.2022.03.003

Abstract

Background: Global shortage of personal protective equipment (PPE), as consequence of the COVID-19 global pandemic, has unmasked significant resource inequities prompting efforts to develop methods for safe PPE decontamination for reuse. The World Health Organization (WHO) in their Rational Use of PPE bulletin cited the use of a photodynamic dye, methylene blue, and light exposure as a viable option for N95 respirator decontamination. Because WHO noted that methylene blue (MB) would be applied to surfaces through which health care workers breathe, we hypothesized that little to no MB will be detectable by spectroscopy when the PPE is subjected to MB at supraphysiologic airflow rates.
Methods: A panel of N95 respirators, medical masks, and cloth masks were sprayed with 5 cycles of 1,000 uM MB solution. Mask coupons were subjected to the equivalent of 120 L/min of 100% humidified air flow. Effluent gas was trapped in an aqueous solution and the resultant fluid was sampled for MB absorbance with a level of detection of 0.004 mg/m3.
Results: No detectable MB was identified for any mask using Ultraviolet-Visible spectroscopy.
Conclusions: At 500-fold the amount of MB applied to N95 respirators and medical masks as were used for the decontamination study cited in the WHO Rational Use of PPE bulletin, no detectable MB was observed, thus providing safety evidence for the use of methylene blue and light exposure for mask decontamination.

Keywords: COVID-19; Coronavirus; Global health; Personal protective equipment (PPE); Photodynamic therapy; Singlet oxygen.