key: cord-0997249-q53ijefa
authors: Pottage, T.; Garratt, I.; Onianwa, O.; Carter, J.; Bennett, A.M.
title: Rapid inactivation of SARS-CoV-2 after exposure to Vapour Hydrogen Peroxide
date: 2021-10-14
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2021.10.007
sha: 79af93def22c8e6d31e72627e7ebad34e0ea46f5
doc_id: 997249
cord_uid: q53ijefa

nan

proposed as a method for decontamination of single-use face masks to avoid supply 18 shortages [3, 4] . The current study investigated the inactivation of SARS-CoV-2 dried from 19 multiple media using a commercial vaporised hydrogen peroxide (VHP) generator (X10, 20

Steris, UK). 21 SARS-CoV-2, England 02/2020 (EPI_ISL_407073), was propagated as described by Paton et al. 22 [5] . The viral stock was used to create two separate suspensions for exposure; A) diluted 1:1 23 with complete minimal essential medium (CMEM), B) diluted 1:1 with artificial saliva (BS EN 24 16711-3:2019) with additional protein (mucin (2.5 mg/ml) and bovine serum albumin (2.0 25 mg/ml)). Suspension A or B (10 µl) was dried onto stainless steel coupons (15 mm diameter) 26 within an operating class III biological safety cabinet for around 2.5 hours. Coupons were 27 then transferred to the flexible film isolator (FFI, 488 litres) for exposure. The X10 generator 28 was connected to the FFI and the smallest preset cycle started, triplicate zero-minute time 29 point coupons were sampled immediately taken by placing each into 1 ml of CMEM plus 30 catalase (VWR, UK). Samples were further taken at 5 and 10 minutes after VHP exposure. 31

Inoculated coupons not exposed to VHP were also made to assess the loss in recovery over 32 the exposure period. Samples were then removed from the FFI and transferred to a class III 33 BSC for processing. Once in the BSC, the drying control coupons were placed into recovery 34 J o u r n a l P r e -p r o o f media and all coupons were processed as described previously by serial dilution and plaque 35 assay using Vero E6 cells [5] . 36 37 After exposure to VHP, no viable SARS-CoV-2 (detection limit 2.5 pfu in each sample) was 41 recovered from any exposure samples taken, producing a log reduction in comparison to the 42 loading at time point zero, of >3.9 logs for SARS-CoV-2 exposed in saliva and protein and 43 >4.4 logs from SARS-CoV-2 exposed in CMEM. The concentration of hydrogen peroxide 44 within the FFI was measured at a peak of 726 ppm at 150 seconds. 45

Hydrogen peroxide technologies have been evaluated previously for their ability to 46 inactivate SARS-CoV-2 dried onto surfaces [6, 7] . These studies used SARS-CoV-2 virus 47 suspended in its propagation media [6] , or in other soil [7] , which does not replicate the 48 presentation of the virus on used face masks from exhaled or sprayborne droplets. To the 49 authors' knowledge, no study has been completed with SARS-CoV-2 suspended in artificial 50 saliva, with added protein and mucin to mimic that of human nasopharyngeal secretions. 51

The presence of additional salts and protein around the virus have previously been shown to 52 have a protective effect on agents exposed to gaseous decontamination [8] leading to 53 incomplete inactivation of the agent. This is particularly important in areas where 54 decontamination processes are chosen for their rapid turnaround time and a more intensive 55 exposure cycle (concentration or time) would be necessary to inactivate the agent. 56

This current study was the first to investigate the inactivation kinetics, taking sampling 57 timepoints, finding inactivation of SARS-CoV-2 to below the detection limit within five 58 minutes of the injection of VHP to the enclosure. It is expected that an enveloped virus 59 would be inactivated quickly as these are generally most easily inactivated by chemical 60 disinfection. However, this study demonstrates that even when additional protective protein 61 and salt media are present on non-porous surfaces, SARS-CoV-2 is rapidly inactivated by 62 

Transmission of SARS-CoV-2: implications for infection 77 prevention precautions

Influenza Virus Infectivity Is Retained in Aerosols and Droplets 79 Independent of Relative Humidity

Effectiveness of N95 Respirator Decontamination and Reuse 81 against SARS-CoV-2 Virus

Decontamination and Reuse of N95 Respirators with Hydrogen Peroxide Vapor to 85

Address Worldwide Personal Protective Equipment Shortages During the SARSCoV-2 86 (COVID-19) Pandemic

Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 88 (SARS-CoV-2) Virus and Viral RNA in Relation to Surface Type and Contamination 89 Concentration

Hydrogen Peroxide Vapor Decontamination of 92

Hazard Group 3 Bacteria and Viruses in a Biosafety Level-3 Laboratory. Applied 93 Biosafety

Vapourized hydrogen peroxide decontamination in a 95 hospital setting inactivates SARS-CoV-2 and HCoV-229E without compromising 96 filtration efficiency of unexpired N95 respirators

Impact of the suspending medium on 99 susceptibility of meticillin-resistant Staphylococcus aureus to hydrogen peroxide 100 vapour decontamination

We thank Professor K. Richards, High Containment Microbiology, PHE, Porton Down, for 67