Evaluation of environmental conditions as a decontamination approach for SARS-CoV-2 when applied to common library, archive and museum-related materials.

AIMS: The purpose of this study was to evaluate the effects of ambient or altered environmental conditions on the inactivation of SARS-CoV-2 applied to materials common in libraries, archives and museums. METHODS AND RESULTS: Porous and non-porous materials (e.g. paper, plastic protective book cover) were inoculated with approximately 1 × 105 TCID50 SARS CoV-2 (USA-WA1/2020), dried, placed within test chamber in either a stacked or unstacked configuration, and exposed to environmental conditions ranging from 4 to 29°C at 40 ± 10% relative humidity. The amount of infectious SARS-CoV-2 was then assessed at various timepoints from 0 to 10 days. Ambient conditions resulted in varying inactivation rates per material type. Virus inactivation rate decreased when materials were stacked or at colder temperatures. Virus inactivation rate increased when materials were unstacked or at warmer temperatures. CONCLUSIONS: SARS-CoV-2 at ambient conditions resulted in the inactivation of virus below limit of quantitation (LOQ) for all materials by Day 8. Warmer temperatures, for a subset of materials, increased SARS-CoV-2 inactivation, and all were

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.

Evaluation of altered environmental conditions as a decontamination approach for SARS-CoV-2 when applied to aircraft related materials.

AIMS: The purpose of this study was to evaluate the effects of altered environmental conditions, specifically elevated temperature at various levels of expected relative humidity (RH), on the inactivation of SARS-CoV-2 when applied to U.S. Air Force aircraft materials. METHODS AND RESULTS: SARS CoV-2 (USA-WA1/2020) was spiked (∼1 × 105 TCID50) in either synthetic saliva or lung fluid, dried onto porous (e.g. Nylon strap) and nonporous materials (e.g. bare aluminum, silicone, and ABS plastic), placed in a test chamber and exposed to environmental conditions ranging from 40 to 51.7 °C and RH ranging from 0% to 50%. The amount of infectious SARS-CoV-2 was then assessed at various timepoints from 0 to 2 days. Warmer test temperatures, higher RH, and longer exposure duration resulted in higher inactivation rates per material type. Synthetic saliva inoculation vehicle was more readily decontaminated compared to materials inoculated with synthetic lung fluid. CONCLUSIONS: SARS-CoV-2 was readily inactivated below limit of quantitation (LOQ) for all materials inoculated using synthetic saliva vehicle within 6 hours when exposed to environmental conditions of 51.7 °C and RH ≥ 25%. Synthetic lung fluid vehicle did not follow the general trend of an increase in RH resulting in increased efficacy. The lung fluid performed best at the 20%-25% RH range to achieve complete inactivation below LOQ.