Vaporized Hydrogen Peroxide Decontamination Research Articles

Enzymatic Indicators in Vaporized Hydrogen Peroxide Decontamination Cycles: Application-related Research focusing on Fractional Kill Time (FKT) and Reverse Fractional Kill Time (RFKT) Studies

The accepted standard from a regulatory perspective for vaporized hydrogen peroxide (vH2O2) cycle validation is the use of biological indicators (BIs). Novel enzymatic indicators (EIs) are gaining more importance in this field, relying on specific enzymatic reactions for their functionality. The aim of this work is to determine how enzymatic indicators can contribute to the cycle development process. Emphasis was placed on the initial informative study, the fractional kill time study, which is a basis for future studies. The results indicate that enzymatic indicators have the potential to facilitate further development of the cycle. This requires an analysis of the determined data, measured in relative light units (RLU), and aligning it with the BI growth, resulting in Full Kill/ No Kill limits. The use of enzymatic indicators for decontamination cycle development opens new perspectives and holds considerable potential for practical use in the development and validation of decontamination processes.

Filtration performance of three models of N95 filtering facepiece respirators following clinical usage and vaporized hydrogen peroxide decontamination

N95 filtering facepiece respirators (FFRs) are essential personal protective equipment (PPE) for protecting healthcare workers from airborne pathogens. To perform the first large-scale evaluation of particulate filtration efficiency (PFE) of three models of N95 FFRs following clinical usage and vaporized hydrogen peroxide (VHP) decontamination. Three variables were assessed for effect on PFE following VHP decontamination: VHP sterilizer model, N95 respirator model, and prior N95 clinical usage. The VHP sterilizer model and N95 FFR model impacted PFE performance. Worn N95 FFRs had a 91% lower odds of exhibiting ≥95% PFE compared with the control. This work highlights the importance of validating any N95 FFR decontamination programme in its entirety, including prior clinical usage.

Validation of N95 respirator mask for the Re-use in the pandemic crisis

The SARS COVID 19 (Severe Acute Respiratory Syndrome Corona Virus Disease 2019) pandemic has created a surge in the need for N95 respirators all across the world. Health care systems are struggling to find a way to cleanse and decontaminate the N95 masks for reuse. To combat the crisis there is a need to validate the N95 mask for efficiency and air filterability on repeated exposure to UV irradiation and vaporized hydrogen peroxide with equal parts of normal saline. To validate N95 respirator mask by using UVGI (Ultra Violet Germicidal Irradiation) method using UV hood and VHP (Vaporized Hydrogen peroxide 6% with equal volume saline 0.9% using an OT fogger machine). VHP decontamination is the method of choice to repeatedly re-sterilize N95 masks. Decontamination by the VHP method is more efficient in killing microorganisms within a short duration of exposure (60 minutes). The method retains the texture of the mask material, re-usability and air filterability even with repeated exposure (up to 10 times). UVGI does sterilize the mask but is inferior to VHP in retaining air filterability.

Hydrogen peroxide vapor decontamination of N95 respirators for reuse.

The coronavirus disease 2019 (COVID-19) pandemic has led to global shortages of N95 respirators. Reprocessing of used N95 respirators may provide a higher filtration crisis alternative, but whether effective sterilization can be achieved for a virus without impairing respirator function remains unknown. We evaluated the viricidal efficacy of Bioquell vaporized hydrogen peroxide (VHP) on contaminated N95 respirators and tested the particulate particle penetration and inhalation and exhalation resistance of respirators after multiple cycles of VHP. For this study, 3M 1870 N95 respirators were contaminated with 3 aerosolized bacteriophages: T1, T7, and Pseudomonas phage phi-6 followed by 1 cycle of VHP decontamination using a BQ-50 system. Additionally, new and unused respirators were sent to an independent laboratory for particulate filter penetration testing and inhalation and exhalation resistance after 3 and 5 cycles of VHP. A single VHP cycle resulted in complete eradication of bacteriophage from respirators (limit of detection 10 PFU). Respirators showed acceptable limits for inhalation/exhalation resistance after 3 and 5 cycles of VHP. Respirators demonstrated a filtration efficiency >99 % after 3 cycles, but filtration efficiency fell below 95% after 5 cycles of HPV. Bioquell VHP demonstrated high viricidal activity for N95 respirators inoculated with aerosolized bacteriophages. Bioquell technology can be scaled for simultaneous decontamination of a large number of used but otherwise intact respirators. Reprocessing should be limited to 3 cycles due to concerns both about impact of clinical wear and tear on fit, and to decrement in filtration after 3 cycles.

Decontaminating N95 Respirators for Reuse in a Hospital Setting.

With the global outbreak of the COVID-19 pandemic, hospitals in Canada and around the world have been forced to consider conservation strategies to ensure continued availability of personal protective equipment (PPE) for healthcare providers. To mitigate critical PPE shortages, Sinai Health System (Sinai Health), a large academic healthcare institution in Canada, has developed and operationalized a standard operating procedure for the collection, decontamination and reuse of N95 respirators and other single-use PPE using a vaporized hydrogen peroxide decontamination method. Sinai Health has incorporated stringent quality assurance steps to ensure that the N95 respirators are successfully decontaminated without deformation and are safe to use.

Decontaminating N95 respirators during the COVID-19 pandemic: simple and practical approaches to increase decontamination capacity, speed, safety and ease of use

BackgroundThe COVID-19 pandemic has caused a severe shortage of personal protective equipment (PPE), especially N95 respirators. Efficient, effective and economically feasible methods for large-scale PPE decontamination are urgently needed.Aims(1) to develop protocols for effectively decontaminating PPE using vaporized hydrogen peroxide (VHP); (2) to develop novel approaches that decrease set-up and take-down time while also increasing decontamination capacity; (3) to test decontamination efficiency for N95 respirators heavily contaminated by make-up or moisturizers.MethodsWe converted a decommissioned Biosafety Level 3 laboratory into a facility that could be used to decontaminate N95 respirators. N95 respirators were hung on metal racks, stacked in piles, placed in paper bags or covered with make-up or moisturizer. A VHP® VICTORY™ unit from STERIS was used to inject VHP into the facility. Biological and chemical indicators were used to validate the decontamination process. Findings: N95 respirators individually hung on metal racks were successfully decontaminated using VHP. N95 respirators were also successfully decontaminated when placed in closed paper bags or if stacked in piles of up to six. Stacking reduced the time needed to arrange N95 respirators for decontamination by approximately two-thirds while almost tripling facility capacity. Make-up and moisturizer creams did not interfere with the decontamination process.ConclusionsRespirator stacking can reduce the hands-on time and increase decontamination capacity. When personalization is needed, respirators can be decontaminated in labelled paper bags. Make up or moisturizers do not appear to interfere with VHP decontamination.

Rapid and accurate evaluation of vaporized hydrogen peroxide on the efficiency of disinfection, using a sensitive dual-channel laser scanning cytometer

Vaporized hydrogen peroxide (VHP) is a highly active disinfectant, and VHP decontamination systems have been widely applied in hospitals, microbiological laboratories, and pharmaceutical industries. However, the decomposition of VHP into non-toxic by-products is essential. Evaluation of the disinfection efficacy of VHP is crucial to ensuring the reliability of VHP disinfection and controlling microbial contamination. In this study, a rapid and sensitive strategy is proposed to evaluate the efficacy of VHP in surface disinfection by detecting the survived and killed bacteria from VHP-exposed biological indicators (BIs). A dual-channel solid-phase cytometer is designed, and fluorescent dyes are used as indicators to automatically and accurately distinguish live cells from dead cells in the mixtures of bacteria. To verify the availability and effectiveness of the laser scanning cytometry, experiments on its application in estimating the efficacy of VHP disinfection practice have been carried out in this study, and its estimation effect compared with that of the traditional plate counting method. Results show that the proposed assay might distinctly identify live or killed cells labeled by green and red fluorescent dyes and examined the disinfection efficacy in 30 min by calculating the bactericidal rate. Compared with the plate counting method, the proposed approach is accurate and practical, with an average detection efficiency of 98.47% ± 1.55%. Moreover, an excellent correlation between the concentrations of B. subtilis var niger (ATCC 9372) measured by the proposed detection system and by the plate counting method is noticed (R2 = 0.9971), indicating that this approach had advantages in the detection of trace microorganisms. To summarize, the proposed strategy appears practical and significant in many fields in which microbial counting and identification are required.

Use, re-use or discard? Quantitatively defined variance in the functional integrity of N95 respirators following vaporized hydrogen peroxide decontamination during the COVID-19 pandemic

BackgroundCoronavirus disease 2019 has stretched the ability of many institutions to supply needed personal protective equipment, especially N95 respirators. N95 decontamination and re-use programmes provide one potential solution to this problem. Unfortunately, a comprehensive evaluation of the effects of decontamination on the fit of various N95 models using a quantitative fit test (QNFT) approach is lacking.AimsTo investigate the effects of up to eight rounds of vaporized hydrogen peroxide (VHP) decontamination on the fit of N95 respirators currently in use in a hospital setting, and to examine if N95 respirators worn by one user can adapt to the face shape of a second user with no compromise to fit following VHP decontamination.MethodsThe PortaCount Pro+ Respirator Fit Tester Model 8038 was used to quantitatively define functional integrity, measured by fit, of N95 respirators following decontamination with VHP.FindingsThere was an observable downward trend in the functional integrity of Halyard Fluidshield 46727 N95 respirators throughout eight cycles of decontamination with VHP. Functional integrity of 3M 1870 N95 respirators was reduced significantly after the respirator was worn, decontaminated with VHP, and then quantitatively fit tested on a second user. Furthermore, inconsistencies between qualitative fit test and QNFT results were uncovered that may have strong implications on the fit testing method used by institutions.ConclusionsThe data revealed variability in the functional integrity of different N95 models after VHP decontamination, and exposed potential limitations of N95 decontamination and re-use programmes.

Examination of Material Compatibilities with Ionized and Vaporized Hydrogen Peroxide Decontamination.

Hydrogen peroxide (HP) decontamination is effective for a wide spectrum of pathogenic microorganisms. However, exposure to HP causes deleterious effects on some materials. The purpose of this study was to examine material compatibilities with ionized and vaporized hydrogen peroxide (iHP and VHP). With regard to iHP, 24 kinds of materials were exposed up to 100 cycles to iHP. The tested materials included plastics, metals, woods and plated or coated goods. The procedure of iHP decontamination was as following: gas time (11 min), dwell time (15 min) and aeration time (120 min). iHP decontamination caused some damage to copper, brass, chromium plate and galvanized iron immediately after exposure. Repeated iHP decontamination caused marked damage in stainless steel and urethane-, silicone- or epoxy-coating materials. Condensation of iHP decontamination posed severe damage for the material surfaces. With regard to VHP, 36 kinds of materials were exposed for up to 200 cycles to VHP decontamination. Under dry (dehumidified) conditions, VHP decontamination caused few changes on the surfaces of resin materials in dry conditions, although some resins began to develop hardening or softening. Discoloration was found in the stainless steel and changes in its coating materials. Bleaching was also observed in wooden materials. Under condensation conditions of VHP, nylon softened and butyl rubber hardened. Condensation of VHP caused material damage such as discoloration in the stainless steel, corrosion of zinc-plated steel, and air-bubbling under the color-steel sheet. The high concentrations of HP with condensation caused severe changes in metals and resins after repeated exposure. The VHP decontamination tests provided evidence that the material damage was more severe under condensation conditions than under dry conditions. Our results demonstrate the importance of condensation of HP when using it to decontaminate equipment.

Vaporized Hydrogen Peroxide Decontamination of N95 Respirators in a Dedicated Animal Research Facility for Reuse During a Novel Coronavirus Pandemic.

Introduction:During the COVID-19 pandemic, health care systems and safety providers have faced an unprecedented challenge of limited access to personal protective equipment (PPE) to conduct patient and public care. In federal emergencies, reuse of PPE after disinfection can occur by processes, like vaporized hydrogen peroxide (VHP), recommended by the Centers for Disease and Control and Prevention. We identified a vacant animal holding facility at our institution to repurpose into a regional VHP decontamination center.Methods:The facility is a multiroom, 20 000 ft2 building with control of HVAC to adjust to VHP conditional requirements. H2O2 was delivered to rooms using robotic HaloFoggers, dispersing H2O2 vapor and increasingly concentrated microdroplets as a fog for a timed period based on cubic footage of rooms.Results:Fogging cycles eliminated 6-log Geobacillus stearothermophilus up to 7 days postcycle. Functional efficacy of treated N95s was confirmed by fit tests of institutional personnel. Signage, process flow mapping, and training materials facilitated ease of workflow and adherence to safety expectations within the building.Discussion and Conclusion:Our study determined that a variety of N95 respirator types and sizes were able to be cleared of potential bacterial and viral agents using VHP in a controlled fog/dwell/exhaust cycle. This repurposed animal facility has the capacity to decontaminate up to 6700 respirators daily, which will address the predicted surge of COVID-19 cases in the state, and ultimately allow each respirator to be reused multiple times. There is no other public site in the region with our capacity to offset the continued supply chain issues for PPE needs.

Impact of extended use and decontamination with vaporized hydrogen peroxide on N95 respirator fit

BackgroundTo address the shortage of N95 respirators in the wake of the COVID-19 pandemic, some organizations have recommended the decontamination of respirators using vaporized hydrogen peroxide (VHP) sterilizer for up to 10 times. However, these recommendations are based on studies that did not take into account the extended use of respirators, which can degrade respirator fit.MethodsWe investigated the impact of extended use and decontamination with VHP on N95 Respirator Fit. We performed a prospective cohort study to determine the number of times respirators can be decontaminated before respirator fit test failure. The primary outcome was the overall number of cycles required for half of the respirators to fail (either mechanical failure or fit test failure).ResultsThirty-six participants completed 360 hours of respirator usage across 90 cycles. The median number of cycles completed by participants before respirator failure was 2. The overall number of cycles required for half of respirators to fail was 1, 3, 5, and 4 for the 3M 1860(S), 3M 1870+, Moldex 151X and ProGear 88020 respirators, respectively.ConclusionsThe combination of prolonged usage and VHP decontamination was associated with early failure. Decontamination and prolonged usage of respirators must be done cautiously.

N95 reprocessing by low temperature sterilization with 59% vaporized hydrogen peroxide during the 2020 COVID-19 pandemic

BackgroundResponse to the COVID-19 pandemic by hospital systems has been strained by severe shortages in personal protective equipment (PPE), particularly N95 respirators. Recently, the Centers for Disease Control and Prevention endorsed decontamination strategies to prolong the lifespan of single use respirators. Battelle and Duke University have validated hospital protocols to decontaminate respirators using vaporized hydrogen peroxide (VHP) at 30%-35% concentrations. To prolong our supply of respirators, we evaluated and implemented VHP decontamination at 59% hydrogen peroxide concentration while detailing the effects of this process on the filtration efficiency and quantitative fit of single-use respirators. This study may help other health systems develop local solutions to their N95 mask shortage during this COVID-19 pandemic.MethodsN95 respirators (3M 8211 FF and 9210 FF) that were treated with 5 and 10 cycles of VHP by the V-PRO maX Low Temperature Sterilization System were evaluated quantitatively for filtration efficiency as well as with quantitative fit testing per Occupational Safety and Health Administration standards. A decontamination protocol was concurrently implemented at our institution. This process involved depositing used masks, reprocessing, and re-distributing treated masks efficiently back to frontline providers. Furthermore, we implemented patient safety officers on COVID-19/person under investigation units to ensure optimized donning/doffing of respirators through frontline provider education.ResultsThere were no statistically significant changes in mean filtration efficiency between the control and VHP-treated respirators. Furthermore, both treated and untreated respirators demonstrated fit factors above the minimum pass requirement.ConclusionsWe have successfully demonstrated that N95 respirator decontamination with VHP at 59% hydrogen peroxide can be safely utilized to decontaminate single-use N95 respirators without significant effects on filtration efficiency or quantitative fit testing. With the COVID-19 pandemic and N95 respirator shortage, health systems without access to commercial decontamination processes should investigate the viability of such a process in their facilities.

Effect of various decontamination procedures on disposable N95 mask integrity and SARS-CoV-2 infectivity.

The COVID-19 pandemic has created a high demand on personal protective equipment, including disposable N95 masks. Given the need for mask reuse, we tested the feasibility of vaporized hydrogen peroxide (VHP), ultraviolet light (UV), and ethanol decontamination strategies on N95 mask integrity and the ability to remove the infectious potential of SARS-CoV-2. Disposable N95 masks, including medical grade (1860, 1870+) and industrial grade (8511) masks, were treated by VHP, UV, and ethanol decontamination. Mask degradation was tested using a quantitative respirator fit testing. Pooled clinical samples of SARS-CoV-2 were applied to mask samples, treated, and then either sent immediately for real-time reverse transcriptase-polymerase chain reaction (RT-PCR) or incubated with Vero E6 cells to assess for virucidal effect. Both ethanol and UV decontamination showed functional degradation to different degrees while VHP treatment showed no significant change after two treatments. We also report a single SARS-CoV-2 virucidal experiment using Vero E6 cell infection in which only ethanol treatment eliminated detectable SARS-CoV-2 RNA. We hope our data will guide further research for evidenced-based decisions for disposable N95 mask reuse and help protect caregivers from SARS-CoV-2 and other pathogens.

Towards an Understanding of the Adsorption of Vaporized Hydrogen Peroxide (VHP) Residues on Glass Vials After a VHP Decontamination Process Using a Miniaturized Tool

Isolators for aseptic filling of biopharmaceuticals and vaccine products are commonly sanitized by vaporized hydrogen peroxide (VHP). However, remaining traces of H2O2 may contaminate the solution and cause oxidative degradation of the pharmaceutical products. The present report aims to establish a thorough understanding of the factors influencing H2O2 adsorption on empty glass intended for pharmaceutical product filling. A lab-scale miniaturized set-up that mimics the VHP- based isolator decontamination process was used. A fractional factorial design of experiment (DoE) was performed including relative humidity (RH), VHP concentration and exposure time as variables. The results revealed that VHP concentration and RH both impacts significantly the extent of H2O2 adsorption on the surface of glass vials and rubber stoppers. The lower extent of H2O2 adsorption at elevated RH implies the existence of competitive co-adsorption. Thus, adsorbed H2O2 may be removed more efficiently from the isolator after the decontamination phase by insufflating air with a high %RH rate during the isolator's aeration phase. The understanding gained from the present set-up can be applied to optimize the design of isolator decontamination cycles and evaluate the trade-off between process performance and the resulting product quality.

Facility-wide Eradication of Corynebacterium bovis by using PCR-validated Vaporized Hydrogen Peroxide.

Facility-wide Corynebacterium bovis eradication was established using vaporized hydrogen peroxide (VHP) decontamination guided by C. bovis PCR surveillance. Prior attempts limited to culling PCR-positive mice and decontaminating affected rooms were ineffective in preventing recurrence. Because research aims often require trafficking to and use of procedural cores, a 12-mo facility-wide C. bovis PCR surveillance of 2064 specimens was performed and documented that, despite the presence of few clinically hyperkeratotic mice, 35% of the murine housing and use space was contaminated by C. bovis. The airways of IVC racks and air-handling units (AHU) provided a substantive niche for C. bovis survival, comparable to the primary enclosure, with 26% of murine and 22% of airway specimens PCR-positive for C. bovis. Equipment airway VHP sterilization in a 'flex room' required an 'active-closed' setting with the IVC rack connected to the AHU set to the VHP cycle, because 12% of specimens from 'static-open' VHP-exposed airways remained PCR-positive for C. bovis, whereas 0% of specimens from active-closed VHP exposures were positive. VHP decontamination of the 29,931-ft2 facility was completed in 2 mo. C. bovis PCR testing of IVC exhaust plenums for 200 d in previously C. bovis-affected rooms confirmed that none of the 259 specimens tested were PCR-positive for the organism. Monthly surveillance identified a single recurrence during June 2017 (month 9), ensuring rapid culling of C. bovis PCR-positive mice and acute VHP decontamination of equipment and rooms. Molecular persistence of C. bovis was resolved in procedural and personnel areas, and no murine or housing specimens tested C. bovis PCR-positive during study months 11 and 12. Furthermore, since the conclusion of the 12-mo study, none of the 452 additional murine, cell biologic, environmental, and monthly equipment surveillance specimens tested were C. bovis PCR-positive, documenting an 11-mo period of facility-wide C. bovis eradication to date. Study invalidation due to C. bovis can be avoided through PCR surveillance for the organism, immediate culling of PCR-positive mice, and acute VHP decontamination of affected areas.

Control of an outbreak of Acinetobacter baumannii infections using vaporized hydrogen peroxide

Multidrug-resistant Acinetobacter baumannii (MRAB) is a serious nosocomial pathogen characterized by its survival on inanimate surfaces for long periods, making control of outbreaks difficult. To analyse two hospital outbreaks caused by MRAB, determine their epidemiology, carbapenem-resistance mechanisms and assess the effectiveness of surface disinfection by vaporized hydrogen peroxide (VHP). MRAB strains were isolated from patients in two intensive care units (ICUs). Antimicrobial susceptibility testing was performed by E-test. Polymerase chain reaction (PCR) was used to detect the presence of the most common A.baumannii carbapenemases. Epidemiological typing was performed by rep-PCR (DiversiLab) and pulsed-field gel electrophoresis. VHP was used to decontaminate the affected ICUs. MRAB was isolated from 28 patients between January 2009 and September 2010. All isolates were resistant to ciprofloxacin and gentamicin. Twenty-one were also resistant to carbapenems. Carbapenem resistance was associated primarily with the acquired OXA-23-like enzyme. Genotyping revealed three clones; the predominant clone corresponded to the international clone (IC) 2. Typing of the isolates pointed to a multifocal outbreak without a single source of infection, with horizontal spread of the dominating clone among ICU patients. A combination of rigorous infection control measures including strict isolation, education of staff, hand hygiene and surface decontamination using VHP halted the outbreak. The results of this study confirm the importance of rigorous infection prevention and control measures, combined with VHP decontamination in controlling an outbreak of MRAB.

Use of Vaporized Hydrogen Peroxide Decontamination during an Outbreak of Multidrug-ResistantAcinetobacter baumanniiInfection at a Long-Term Acute Care Hospital

To describe vaporized hydrogen peroxide (VHP) as an adjuvant in the control of multidrug-resistant (MDR) Acinetobacter baumannii infection in a long-term acute care hospital (LTACH) and to describe the risk factors for acquisition of MDR A. baumannii infection in the LTACH population. Outbreak investigation, case-control study, and before-after intervention trial. A 54-bed LTACH affiliated with a tertiary care center in northeastern Ohio. Investigation of outbreak with clinical and environmental cultures, antimicrobial susceptibility testing, polymerase chain reaction assay of repetitive chromosomal elements to type strains, and case-control study; and intervention consisting of comprehensive infection control measures and VHP environmental decontamination. Thirteen patients infected or colonized with MDR A. baumannii were identified from January 2008 through June 2008. By susceptibility testing, 10 (77%) of the 13 isolates were carbapenem-resistant. MDR A. baumannii was found in wound samples, blood, sputum, and urine. Wounds were identified as a risk factor for MDR A. baumannii colonization. Ventilator-associated pneumonia was the most common clinical syndrome caused by the pathogen, and the associated mortality was 14% (2 of the 13 case patients died). MDR A. baumannii was found in 8 of 93 environmental samples, including patient rooms and a wound care cart; environmental and clinical cultures were genetically related. Environmental cultures were negative immediately after VHP decontamination and both 24 hours and 1 week after VHP decontamination. Nosocomial acquisition of the pathogen in the LTACH ceased after VHP intervention. When patients colonized with MDR A. baumannii reoccupied rooms, environmental contamination recurred. Environmental decontamination using VHP combined with comprehensive infection control measures interrupted nosocomial transmission of MDR A. baumannii in an LTACH. The application of this novel approach to halt the transmission of MDR A. baumannii warrants further investigation.