Inanimate objects or surfaces contaminated with infectious agents, referred to as fomites, play an important role in the spread of viruses, including SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The long persistence of viruses (hours to days) on surfaces calls for an urgent need for effective surface disinfection strategies to intercept virus transmission and the spread of diseases. Elucidating the physicochemical processes and surface science underlying the adsorption and transfer of virus between surfaces, as well as their inactivation, is important for understanding how diseases are transmitted and for developing effective intervention strategies. This review summarizes the current knowledge and underlying physicochemical processes of virus transmission, in particular via fomites, and common disinfection approaches. Gaps in knowledge and the areas in need of further research are also identified. The review focuses on SARS-CoV-2, but discussion of related viruses is included to provide a more comprehensive review given that much remains unknown about SARS-CoV-2. Our aim is that this review will provide a broad survey of the issues involved in fomite transmission and intervention to a wide range of readers to better enable them to take on the open research challenges.

SUMMARYIn healthcare settings, contaminated surfaces play an important role in the transmission of nosocomial pathogens potentially resulting in healthcare-associated infections (HAI). Pathogens can be transmitted directly from frequent hand-touch surfaces close to patients or indirectly by staff and visitors. HAI risk depends on exposure, extent of contamination, infectious dose (ID), virulence, hygiene practices, and patient vulnerability. This review attempts to close a gap in previous reviews on persistence/tenacity by only including articles (<i>n</i> = 171) providing quantitative data on re-cultivable pathogens from fomites for a better translation into clinical settings. We have therefore introduced the new term "replication capacity" (RC). The RC is affected by the degree of contamination, surface material, temperature, relative humidity, protein load, organic soil, UV-light (sunlight) exposure, and pH value. In general, investigations into surface RC are mainly performed <i>in vitro</i> using reference strains with high inocula. <i>In vitro</i> data from studies on 14 Gram-positive, 26 Gram-negative bacteria, 18 fungi, 4 protozoa, and 37 viruses. It should be regarded as a worst-case scenario indicating the upper bounds of risks when using such data for clinical decision-making. Information on RC after surface contamination could be seen as an opportunity to choose the most appropriate infection prevention and control (IPC) strategies. To help with decision-making, pathogens characterized by an increased nosocomial risk for transmission from inanimate surfaces ("fomite-borne") are presented and discussed in this systematic review. Thus, the review offers a theoretical basis to support local risk assessments and IPC recommendations.

Viruses contribute significantly to the burden of infectious diseases worldwide. Although there are multiple infection routes associated with viruses, it is important to break the chain of infection and thus consider all possible transmission routes. Consequently, laundering can be a means to eliminate viruses from textiles, in clinical settings well as for domestic laundry procedures. Several factors influence the survival and inactivation of microorganisms, including viruses on hard surfaces and textiles. Therefore, textiles should be regarded as potential fomites. While in clinical and industrial settings laundry hygiene is ensured by standardized processes, temperatures of at least 60 °C and the use of oxidizing agents, domestic laundry is not well defined. Thus, the parameters affecting viral mitigation must be understood and prudently applied, especially in domestic laundering. Laundering can serve as a means to break the chain of infection for viral diseases by means of temperature, time, chemistry and mechanical action.

The role of personal protective equipment (PPE) in protecting against exposure to infectious agents and toxic chemicals is well-established. However, the global surge in PPE demand during the pandemic exposed challenges, including shortages and environmental impacts from disposable waste. Developing effective, scalable, and sustainable decontamination methods for the reuse of PPE is essential. Ozone has emerged as a promising, eco-friendly disinfectant due to its strong oxidative properties, rapid action, and residue-free breakdown into oxygen. This study evaluates the effectiveness of the FATHHOME Trinion Disinfector, an innovative ozone-based dry sterilization device, for inactivating pathogens on PPE materials, such as not resistant to oil 95 (N95) masks and face shields. The device's bactericidal performance was tested against <i>Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhimurium, Enterococcus durans, Enterococcus faecalis</i>, and <i>Saccharomyces cerevisiae</i>, achieving a 1- to 2-log reduction in these bacterial and fungal pathogens. A 30-minute ozone exposure cycle was found to attain maximum sterilization efficiency. We also demonstrated the disinfector's efficacy against viral pathogens, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), adeno-associated virus (AAV), herpes simplex virus type 1 (HSV-1), and hepatitis B virus (HBV) on PPE surfaces. SARS-CoV-2 contamination on face shields and N95 masks decreased by 99.9 %, and AAV infectivity was nearly eliminated. Similar reductions were observed for HSV-1 and HBV. Overall, the findings confirm that ozone-based disinfection offers a rapid, scalable, and sustainable method for decontaminating PPE. These results support the establishment of standardized ozone disinfection protocols to enhance infection control, address PPE shortages, and minimize environmental waste. No previous research has thoroughly assessed its effectiveness against both enveloped and non-enveloped viruses, bacteria, and yeast on PPE surfaces under dry conditions. • New findings: The FATHHOME Trinion Disinfector achieved over 99.9 % inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and adeno-associated virus (AAV), and a 99 % reduction of herpes simplex virus type 1 (HSV-1) and hepatitis B virus (HBV) within 10 min at 60 ppm ozone. Bacterial and fungal pathogens, including Escherichia coli, Staphylococcus aureus , and Saccharomyces cerevisiae , showed more than 90 % reduction after 30 min. The device’s bactericidal performance was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhimurium, Enterococcus durans, Enterococcus faecalis , and Saccharomyces cerevisiae , achieving a 1- to 2-log reduction in these bacterial and fungal pathogens. A 30-minute ozone exposure cycle was found to attain maximum sterilization efficiency. We also demonstrated the disinfector’s efficacy against viral pathogens, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), adeno-associated virus (AAV), herpes simplex virus type 1 (HSV-1), and hepatitis B virus (HBV) on PPE surfaces. 2.4.5 HBV inactivation assay The experimental procedures outlined above for AAV and HSV were used for the inactivation of HBV, except for the downstream assay to detect residual infectious virus. After ozone treatment, an immunolocalization assay Abbreviations: GFP, green fluorescent protein; AAV, adeno-associated virus; ppm, parts per million; O 3 , ozone; N95, not resistant to oil 95. 3.4 Effectiveness of ozone exposure for disinfecting PPE contaminated with HSV We also assessed the effectiveness of ozone exposure using the FATHHOME device in inactivating HSV-1 on PPE, specifically face shields and N95 masks. Fig. 5 A shows representative plaque assay images comparing residual infectious virus on PPE surfaces after ozone treatment with samples that were not exposed to ozone. PPE exposed to 60 ppm ozone for 10 min had a significantly lower number of plaques than the controls, indicating effective inactivation of HSV-1. A) Infectious virus particles in the no O 3 (control) and O 3 (treated) face shield and N95 face mask supernatants were determined via plaque assay. Supernatant volumes (50 µL, 5 µL, and 0.5 µL) derived from the HSV control and test with ozone were tested. B) Quantification of the number of infectious virus particles on face shields and N95 masks after exposure to ozone or no ozone treatment. *, P < 0.05; ** , P < 0.01. Abbreviations: HSV, herpes simplex virus; ppm, parts per million; O 3 , ozone; N95, not resistant to oil 95. 3.5 Effectiveness of ozone exposure for disinfecting PPE contaminated with the hepatitis B virus We further evaluated the effect of ozone exposure on the inactivation of HBV present on PPE using our FATHHOME device. Similar to previous methods, the face shield and an N95 face mask contaminated with droplets carrying the infectious virus were subjected to ozone inactivation, followed by recovery of any residual virus to assess the efficacy of HBV inactivation from the PPE surfaces. The amounts of residual infectious viruses were estimated by counting the number of infected cells defined by the presence of a red signal for viral (HBV core) antigen present in the cells. Fig. Our study demonstrated that a 10-minute exposure to 60 ppm ozone can significantly reduce the levels of infectious viruses on contaminated PPE. We achieved a 3-log reduction (99.90 %) of SARS-CoV-2 and AAV, and a 2-log reduction (99.00 %) for HSV. HBV also showed a substantial decrease in residual infectious viruses, especially on face shields and solid surfaces, highlighting FATHHOME’s potential for decontaminating PPE to reduce the risk of virus transmission. These results confirm that our device can effectively inactivate both enveloped and non-enveloped viruses by oxidizing viral lipid envelopes and capsid proteins, making them non-infectious [ 30 , 31 ].