Decontamination of SARS-CoV-2 contaminated N95 filtering facepiece respirators (FFRs) with moist heat generated by a multicooker

Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials

AIMS

The purpose of this study was to evaluate the efficacy of steam heat for inactivation of SARS-CoV-2 when applied to materials common in mass transit installations.

METHODS AND RESULTS

SARS CoV-2 (USA-WA1/2020) was resuspended in either cell culture media or synthetic saliva, inoculated (∼1 × 106 TCID50) onto porous and nonporous materials and subjected to steam inactivation efficacy tests as either wet or dried droplets. The inoculated test materials were exposed to steam heat ranging from 70°C to 90°C. The amount of infectious SARS-CoV-2 remaining after various exposure durations ranging from 1 to 60 s was assessed. Higher steam heat application resulted in higher inactivation rates at short contact times. Steam applied at 1-inch distance (∼90°C at the surface) resulted in complete inactivation for dry inoculum within 2 s of exposure (excluding two outliers of 19 test samples at the 5-s duration) and within 2-30 s of exposure for wet droplets. Increasing the distance to 2 inches (∼70°C) also increased the exposure time required to achieve complete inactivation to 15 or 30 s for materials inoculated with saliva or cell culture media, respectively.

CONCLUSIONS

Steam heat can provide high levels of decontamination (>3 log reduction) for transit-related materials contaminated with SARS-CoV-2 using a commercially available steam generator with a manageable exposure time of 2-5 s.

Disinfection methods against SARS-CoV-2: a systematic review

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease 2019, has caused millions of deaths worldwide. The virus is transmitted by inhalation of infectious particles suspended in the air, direct deposition on mucous membranes and indirect contact via contaminated surfaces. Disinfection methods that can halt such transmission are important in this pandemic and in future viral infections.

Aim

To highlight the efficacy of several disinfection methods against SARS-CoV-2 based on up-to-date evidence found in the literature.

Methods

Two databases were searched to identify studies that assessed disinfection methods used against SARS-CoV-2. In total, 1229 studies were identified and 60 of these were included in this review. Quality assessment was evaluated by the Office of Health Assessment and Translation's risk-of-bias tool.

Findings

Twenty-eight studies investigated disinfection methods on environmental surfaces, 16 studies investigated disinfection methods on biological surfaces, four studies investigated disinfection methods for airborne coronavirus, and 16 studies investigated methods used to recondition personal protective equipment (PPE).

Conclusions

Several household and hospital disinfection agents and ultraviolet-C (UV-C) irradiation were effective for inactivation of SARS-CoV-2 on environmental surfaces. Formulations containing povidone-iodine can provide virucidal action on the skin and mucous membranes. In the case of hand hygiene, typical soap bars and alcohols can inactivate SARS-CoV-2. Air filtration systems incorporated with materials that possess catalytic properties, UV-C devices and heating systems can reduce airborne viral particles effectively. The decontamination of PPE can be conducted safely by heat and ozone treatment.

Chemical design principles of next-generation antiviral surface coatings

The ongoing coronavirus disease 2019 (COVID-19) pandemic has accelerated efforts to develop high-performance antiviral surface coatings while highlighting the need to build a strong mechanistic understanding of the chemical design principles that underpin antiviral surface coatings. Herein, we critically summarize the latest efforts to develop antiviral surface coatings that exhibit virus-inactivating functions through disrupting lipid envelopes or protein capsids. Particular attention is focused on how cutting-edge advances in material science are being applied to engineer antiviral surface coatings with tailored molecular-level properties to inhibit membrane-enveloped and non-enveloped viruses. Key topics covered include surfaces functionalized with organic and inorganic compounds and nanoparticles to inhibit viruses, and self-cleaning surfaces that incorporate photocatalysts and triplet photosensitizers. Application examples to stop COVID-19 are also introduced and demonstrate how the integration of chemical design principles and advanced material fabrication strategies are leading to next-generation surface coatings that can help thwart viral pandemics and other infectious disease threats.