Fomite Transmission Research Articles

Awareness and Preparedness of Fomite Transmission Among Malaysian Online Shoppers: A Cross-Sectional Survey

Introduction: COVID-19 outbreak is the greatest communicable disease that hit globally, caused by SARS-CoV-2 virus. Malaysia commenced a Movement Control Order (MCO) to contain the epidemic, and thereby altered consumer’s purchasing pattern drastically into online shopping, thus increase the demand of delivery services. The virus able to survive on surfaces up until 9 days depending on the type of surface. Nonetheless, the negligence of proper hygiene management among the vendor, the courier or the user can trigger fomite transmission. The aims of this study were to determine the level of awareness and readiness of fomite transmission caused by COVID-19 among Malaysian online shoppers by evaluating knowledge, precautionary measurements and psychological state. Methods: Convenience sampling method was used for data collection, and 416 respondents participated. The survey instrument comprised of 2 parts; socio-demographic characteristics and the second part consist of COVID-19 transmission as well as its survivability, precautions and psychological state during the outbreak. This was transferred to a Google form and the link was shared through social medias. Data were analysed using SPSS software v.23.0. Results: In spite of the fact that 88% of respondents worried about being infected with COVID-19 and well informed regarding fomite transmission, almost half of respondents (42.3%) did not sanitize their parcels received from outside. Conclusion: In light of this, health authorities should implement more campaigns to emphasize the utmost importance of disinfection of any foreign items by consumers and it is strongly believed that it will provide enhanced protection against fomite transmission.

Variability in Donor Lung Culture and Relative Humidity Impact the Stability of 2009 Pandemic H1N1 Influenza Virus on Nonporous Surfaces.

Respiratory viruses can be transmitted by multiple modes, including contaminated surfaces, commonly referred to as fomites. Efficient fomite transmission requires that a virus remain infectious on a given surface material over a wide range of environmental conditions, including different relative humidities. Prior work examining the stability of influenza viruses on surfaces has relied upon virus grown in media or eggs, which does not mimic the composition of virus-containing droplets expelled from the human respiratory tract. In this study, we examined the stability of the 2009 pandemic H1N1 (H1N1pdm09) virus on a variety of nonporous surface materials at four different humidities. Importantly, we used virus grown in primary human bronchial epithelial cell (HBE) cultures from different donors to recapitulate the physiological microenvironment of expelled viruses. We observed rapid inactivation of H1N1pdm09 on copper under all experimental conditions. In contrast to copper, viruses were stable on polystyrene plastic, stainless steel, aluminum, and glass, at multiple relative humidities, but greater decay on acrylonitrile butadiene styrene (ABS) plastic was observed at short time points. However, the half-lives of viruses at 23% relative humidity were similar among noncopper surfaces and ranged from 4.5 to 5.9 h. Assessment of H1N1pdm09 longevity on nonporous surfaces revealed that virus persistence was governed more by differences among HBE culture donors than by surface material. Our findings highlight the potential role of an individual's respiratory fluid on viral persistence and could help explain heterogeneity in transmission dynamics. IMPORTANCE Seasonal epidemics and sporadic pandemics of influenza cause a large public health burden. Although influenza viruses disseminate through the environment in respiratory secretions expelled from infected individuals, they can also be transmitted by contaminated surfaces where virus-laden expulsions can be deposited. Understanding virus stability on surfaces within the indoor environment is critical to assessing influenza transmission risk. We found that influenza virus stability is affected by the host respiratory secretion in which the virus is expelled, the surface material on which the droplet lands, and the ambient relative humidity of the environment. Influenza viruses can remain infectious on many common surfaces for prolonged periods, with half-lives of 4.5 to 5.9 h. These data imply that influenza viruses are persistent in indoor environments in biologically relevant matrices. Decontamination and engineering controls should be used to mitigate influenza virus transmission.

MERS-CoV Found in Hyalomma dromedarii Ticks Attached to Dromedary Camels at a Livestock Market, United Arab Emirates, 2019.

The main mode of transmission of Middle East respiratory syndrome-related coronavirus (MERS-CoV) between dromedaries is likely via the respiratory route. However, there must be other modes to explain how the infection is brought to MERS-CoV-negative closed herds, such as transmission by ticks. Here, we present a study performed at three different locations in the United Arab Emirates (UAE) involving 215 dromedary camels (Camelus dromedarius) and the ticks attached to them. We tested the camels and ticks via RT-(q)PCR for the presence of MERS-CoV nucleic acids, as well as flaviviruses that may be present in the region (e.g., Alkhumra hemorrhagic fever virus). Camel sera were additionally analyzed for evidence of previous exposure to MERS-CoV. In total, 8 out of 242 tick pools were positive for MERS-CoV RNA (3.3%; Ct 34.6-38.3), 7 of which contained Hyalomma dromedarii ticks, and one contained a Hyalomma sp. tick (species not identified). All of the virus-positive ticks' host camels were also positive for MERS-CoV RNA in their nasal swab samples. Short sequences established in the N gene region from two positive tick pools were identical to viral sequences from their hosts' nasal swabs. In total, 59.3% of dromedaries at the livestock market had MERS-CoV RNA in their nasal swabs (Ct 17.7-39.5). While dromedaries at all locations were negative for MERS-CoV RNA in their serum samples, antibodies were detected in 95.2% and 98.7% of them (tested by ELISA and indirect immunofluorescence test, respectively). Given the probably transient and/or low level of MERS-CoV viremia in dromedaries and the rather high Ct values observed in the ticks, it seems unlikely that Hyalomma dromedarii is a competent vector for MERS-CoV; however, its role in mechanical or fomite transmission between camels should be investigated.

Effects of portable air filtration on submicrometer- and micrometer-sized particle deposition and concentration in a natural ventilated skilled nursing facility

Older adults are highly vulnerable to respiratory diseases. Effective engineering controls are critical to reduce transmission risk via airborne particles, particularly in spaces where older adults reside (e.g., skilled nursing facilities; SNF). We thus investigated how recirculating portable air filtration (PAF) units and natural ventilation influenced airborne particle travel via the direct aerosol (i.e., representing airborne transmission) and indirect aerosol (i.e., representing fomite transmission) routes. A breathing simulator atomized fluorescein-tagged submicrometer- (0.6–0.7 μm) and micrometer-sized (2 μm) particles simultaneously utilizing a physiologically-correct inhalation-exhalation waveform, with the breathing simulator outlet connected to an anatomically-correct respiratory manikin. Experiments involved two SNF resident rooms, the ‘infector’ and ‘susceptible’ rooms, with the former room containing the breathing simulator (i.e., proxy infected resident) and the latter room representing a susceptible resident's room. Observations revealed that despite PAF units enhancing deposition velocities for submicrometer- and micrometer-sized particles, effective deposition fluxes of submicrometer-sized particles were significantly lower during PAF use versus the Baseline Condition. Further, PAF units increased the effective air exchange rate by ∼3.7–4.5x for submicrometer- and micrometer-sized particles, respectively, resulting in significantly lower particle concentrations (>60%) for these particle sizes versus the Baseline Condition. While natural ventilation significantly reduced submicrometer- and micrometer-sized particle concentration and deposition, cross contamination between rooms was identified when natural ventilation was the singular ventilation solution. Observations validated our previous studies in that particle deposition is non-negligible in smaller rooms with poor ventilation and that PAF units are recommended to supplement natural ventilation and best limit airborne particle concentration and deposition.

Innovate and Stockpile: Respiratory Protection for Essential Workers in a Catastrophic Pandemic.

Innovate and Stockpile: Respiratory Protection for Essential Workers in a Catastrophic Pandemic.

Comparative Aerosol and Surface Stability of SARS-CoV-2 Variants of Concern.

SARS-CoV-2 transmits principally by air; contact and fomite transmission may also occur. Variants of concern are more transmissible than ancestral SARS-CoV-2. We found indications of possible increased aerosol and surface stability for early variants of concern, but not for the Delta and Omicron variants. Stability changes are unlikely to explain increased transmissibility.

Assessing the potential for fomite transmission of SARS-CoV-2

Assessing the potential for fomite transmission of SARS-CoV-2

Mpox in Young Woman with No Epidemiologic Risk Factors, Massachusetts, USA.

We describe a case of mpox characterized by a circularly distributed facial rash but no identified risk factors. Fomite transmission of monkeypox virus from contaminated linen at a massage spa was suspected. Clinicians should consider mpox in patients with consistent clinical syndromes, even in the absence of epidemiologic risk factors.

Review of animal transmission experiments of respiratory viruses: Implications for transmission risk of SARS-COV-2 in humans via different routes.

Exploring transmission risk of different routes has major implications for epidemic control. However, disciplinary boundaries have impeded the dissemination of epidemic information, have caused public panic about "air transmission," "air-conditioning transmission," and "environment-to-human transmission," and have triggered "hygiene theater." Animal experiments provide experimental evidence for virus transmission, but more attention is paid to whether transmission is driven by droplets or aerosols and using the dichotomy to describe most transmission events. Here, according to characteristics of experiment setups, combined with patterns of human social interactions, we reviewed and grouped animal transmission experiments into four categories-close contact, short-range, fomite, and aerosol exposure experiments-and provided enlightenment, with experimental evidence, on the transmission risk of severe acute respiratory syndrome coronavirus (SARS-COV-2) in humans via different routes. When referring to "air transmission," context should be showed in elaboration results, rather than whether close contact, short or long range is uniformly described as "air transmission." Close contact and short range are the major routes. When face-to-face, unprotected, horizontally directional airflow does promote transmission, due to virus decay and dilution in air, the probability of "air conditioning transmission" is low; the risk of "environment-to-human transmission" highly relies on surface contamination and human behavior based on indirect path of "fomite-hand-mucosa or conjunctiva" and virus decay on surfaces. Thus, when discussing the transmission risk of SARS-CoV-2, we should comprehensively consider the biological basis of virus transmission, environmental conditions, and virus decay. Otherwise, risk of certain transmission routes, such as long-range and fomite transmission, will be overrated, causing public excessive panic, triggering ineffective actions, and wasting epidemic prevention resources.

Umbilicated vesicles and multiple pustules on the genital area in a man

Umbilicated vesicles and multiple pustules on the genital area in a man

Impact of Plastic-Wrap Properties and Cleaning Intervals on the Disinfection of Elevator Buttons.

Fomite transmission is a possible route by which different pathogens spread within facilities. In hospital settings, elevator buttons are widely observed to be covered with various types of plastic wraps; however, limited information is available concerning the impact of different plastic materials on cleaning. Our study aimed to identify which plastic material is suitable for the coverage of elevator buttons and the optimal intervals for their cleaning. We tested six plastic covers, including polyethylene (PE), polymethylpentene (PMP), polyvinyl chloride (PVD), and polyvinylidene chloride (PVDC) plastic wraps; a thermoplastic polyurethane (TPU) keyboard cover; and a polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) laminating film, which are plastic films. The bioburden on the elevator buttons at different time intervals was measured using an adenosine triphosphate (ATP) bioluminescence assay. Our results show that wraps made of PVDC had superior durability compared with those of PMP, PVC, and PVDC, in addition to the lowest detectable ATP levels among the six tested materials. Regarding different button locations, the highest ATP values were found in door-close buttons followed by door-open, and first-floor buttons after one- and three-hour intervals (p = 0.024 and p < 0.001, respectively). After routine disinfection, the ATP levels of buttons rapidly increased after touching and became more prominent after three hours (p < 0.05). Our results indicate that PVDC plastic wraps have adequate durability and the lowest residual bioburden when applied as covers for elevator buttons. Door-close and -open buttons were the most frequently touched sites, requiring more accurate and precise disinfection; therefore, cleaning intervals of no longer than three hours may be warranted.

Infection control behaviours, intra‐household transmission and quarantine duration: a retrospective cohort analysis of COVID‐19 cases

ObjectivesTo study COVID‐19 (Delta Variant) cases and close contacts co‐located within households. Focusing on epidemiology of transmission of COVID‐19, quarantine duration and utilisation of infection control behaviours under a telehealth model of care in an elimination setting. MethodsA retrospective cohort analysis examined household spread of infection, duration of quarantine and change in PCR CT value during illness. A survey explored infection control behaviours used by household members during isolation and quarantine. ResultsThe cohort was 141 individuals in 35 households. Thirty‐seven were index cases, and 48 became positive during quarantine, most within 10 days. Whole‐household infection occurred in 12 households with multiple members. Behaviours focused on fomite transmission reduction rather than preventing aerosol transmission. The median duration of close contact household quarantine was 25 days. The majority of COVID‐19 cases were de‐isolated after 14 days with no evidence of further community transmission. ConclusionIntrahousehold transmission was not universal and, if it occurred, usually occurred quickly. Behaviours utilised focused on fomites, suggesting a need for improved education regarding the potential utilisation of strategies to prevention the transmission of aerosols. Households experienced long durations of home‐based quarantine. Implications for public healthThe impact of long quarantine durations must be considered, particularly where most community benefit from quarantine is achieved within 10 days from exposure in the setting of the Delta Variant. Education of households regarding aerosol risk reduction is a potential strategy in the household setting of individuals at risk of disease progression.

Household characteristics associated with surface contamination of SARS-CoV-2 and frequency of RT-PCR and viral culture positivity-California and Colorado, 2021.

While risk of fomite transmission of SARS-CoV-2 is considered low, there is limited environmental data within households. This January-April 2021 investigation describes frequency and types of surfaces positive for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (RT-PCR) among residences with ≥1 SARS-CoV-2 infection, and associations of household characteristics with surface RT-PCR and viable virus positivity. Of 1232 samples from 124 households, 27.8% (n = 342) were RT-PCR positive with nightstands (44.1%) and pillows (40.9%) most frequently positive. SARS-CoV-2 lineage, documented household transmission, greater number of infected persons, shorter interval between illness onset and sampling, total household symptoms, proportion of infected persons ≤12 years old, and persons exhibiting upper respiratory symptoms or diarrhea were associated with more positive surfaces. Viable virus was isolated from 0.2% (n = 3 samples from one household) of all samples. This investigation suggests that while SARS-CoV-2 on surfaces is common, fomite transmission risk in households is low.

Photodynamic inactivation of SARS-CoV-2 on inanimate surfaces

Since coronaviruses can remain infectious on different inanimate surfaces for several hours or even days, the possibility of indirect fomite transmission through infected objects and surfaces cannot be ruled out. We describe a method for the photodynamic disinfection of inanimate surfaces infected with severe acute respiratory syndrome coronavirus 2, Omicron variant strain. Application of only 5 µM photosensitizer octakis(cholinyl)zinc phthalocyanine followed immediately by 7 min irradiation with light emitting diode (LED) light 692 nm (12.5 mW cm−2) results in complete inactivation of the virus on polystyrene and glass surfaces, while 10 min irradiation lead to complete eradication of the virus also on Al-foil and medical mask fabric. A photodynamic technique is being considered to combat the spread of coronaviruses.

A hand-targeted auxiliary personal protective equipment for intervention of fomite transmission of viruses.

In COVID‐19, fomite transmission has been shown to be a major route for the spreading of the SARS‐CoV‐2 virus due to its ability to remain on surfaces for extended durations. Although glove wearing can mitigate the risk of viral transmission especially on high touch points, it is not prevalent due to concerns on diversion of frontline medical resources, cross‐contamination, social stigma, as well as discomfort and skin reactions derived from prolonged wearing. In this study, we developed FlexiPalm, a hand‐targeted auxiliary personal protective equipment (PPE) against fomite transmission of viruses. FlexiPalm is a unique palmar‐side hand protector designed to be skin‐conforming and transparent, fabricated from medical‐grade polyurethane transparent film material as a base substrate. It serves primarily as a barrier to microbial contamination like conventional gloves, but with augmented comfort and inconspicuousness to encourage a higher public adoption rate. Compared to conventional glove materials, FlexiPalm demonstrated enhanced mechanical durability and breathability, comparable hydrophobicity, and displayed a minimal adsorption of SARS‐CoV‐2 spike protein and virus‐like particles (VLP). Importantly, FlexiPalm was found to bind significantly less viral protein and VLP than artificial human skin, confirming its ability to reduce viral contamination. A pilot study involving participants completing activities of daily living showed a high level of comfort and task completion, illustrating the usability and functionality of FlexiPalm. Moreover, we have demonstrated that surface modification of FlexiPalm with microtextures enables further reduction in viral adsorption, thereby enhancing its functionality. An effective implementation of FlexiPalm will bolster PPE sustainability and lead to a paradigm shift in the global management of COVID‐19 and other infectious diseases in general.

Viral cultures for assessing fomite transmission of SARS-CoV-2: a systematic review and meta-analysis

IntroductionThe role of fomites in the transmission of SARS-CoV-2 is unclear. Our objective was to assess whether SARS-CoV-2 can be transmitted through fomites, using evidence from viral culture studies.MethodsWe conducted searches in the WHO Covid-19 Database, PubMed, LitCovid, medRxiv, and Google Scholar to 31 December 2021. We included studies that investigated fomite transmission and performed viral culture to assess the cytopathic effect (CPE) of positive fomite samples and confirmation of SARS-CoV-2 as the cause of the CPE. We assessed the risk of bias using a checklist modified from the QUADAS-2 criteria.ResultsWe included 23 studies. The overall risk of bias was moderate. Five studies demonstrated replication-competent virus from fomite cultures and three used genome sequencing to match fomite samples with human clinical specimens. The mean Ct of samples with positive viral culture was significantly lower compared with cultured samples that returned negative results: SMD -1.45, 95%CI -2.00 to -0.90, I2=0%; P<0.00001. The likelihood of isolating replication-competent virus was significantly greater when the Ct was <30: RR 3.10 (95%CI 1.32 to 7.31, I2=71%, P=0.01). Infectious specimens were mostly detected within 7 days of symptom onset. One study showed possible transmission of SARS-CoV-2 from fomites to humans.ConclusionThe evidence from published studies suggests that replication-competent SARS-CoV-2 is present on fomites. Replication-competent SARS-CoV-2 is significantly more likely when the PCR Ct for clinical specimens and fomite samples is <30. Further studies should investigate the duration of infectiousness of SARS-CoV-2 and the frequency of transmission from fomites.

Stability and transmissibility of SARS-CoV-2 in the environment.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the virus causing the ongoing global coronavirus disease 2019 (COVID‐19) pandemic, is believed to be transmitted primarily through respiratory droplets and aerosols. However, reports are increasing regarding the contamination of environmental surfaces, shared objects, and cold‐chain foods with SARS‐CoV‐2 RNA and the possibility of environmental fomite transmission of the virus raises much concern and debate. This study summarizes the current knowledge regarding potential mechanisms of environmental transmission of SARS‐CoV‐2, including the prevalence of surface contamination in various settings, the viability and stability of the virus on surfaces or fomites, as well as environmental factors affecting virus viability and survival such as temperature and relative humidity. Instances of fomite transmission, including cold‐chain food transmission, and the importance of fomite transmission in epidemics, are discussed. The knowledge gaps regarding fomite transmission of SARS‐CoV‐2 are also briefly analyzed.

ANALYSIS OF COVID-19 FOMITE TRANSMISSION MODEL WITH DISINFECTANT SPRAY

The SARS-CoV-2 virus causes the infectious disease COVID-19. This virus can be transmitted via the fomite mode of transmission (the surface of objects contaminated with the virus). It is possible to prevent the spread of COVID-19 by spraying disinfectant on infected objects. This research aims to develop a mathematical model of COVID-19 fomite transmission with disinfectant spraying intervention. The model was analyzed by determining its stability and critical point. A Ro analysis was conducted to determine the impact of disinfectant spraying on the eradication or spread of the disease. The results demonstrated that, in the absence of disinfectant spraying, the number of infected humans increased rapidly and abruptly. Based on the findings of sensitivity analysis, it is known that spraying disinfectants is highly effective at reducing Ro, thereby reducing the number of infected humans and eradicating the disease from the population. In this study, the recommended measure to prevent the spread of COVID-19 is the periodic application of disinfectant in accordance with medical regulations.

Monkeypox virus contamination in an office-based workplace environment

Monkeypox virus contamination in an office-based workplace environment

Evaluating fomite risk of brown paper bags storing personal protective equipment exposed to SARS-CoV-2: A quasi-experimental study.

Literature is lacking on the safety of storing contaminated PPE in paper bags for reuse, potentially increasing exposure to frontline healthcare workers (HCW) and patients. The aim of this study is to evaluate the effectiveness of paper bags as a barrier for fomite transmission of SARS-CoV-2 by storing face masks, respirators, and face shields. This quasi-experimental study evaluated the presence of SARS-CoV-2 on the interior and exterior surfaces of paper bags containing PPE that had aerosolized exposures in clinical and simulated settings. Between May and October 2020, 30 unique PPE items were collected from COVID-19 units at two urban hospitals. Exposed PPE, worn by either an infected patient or HCW during a SARS-CoV-2 aerosolizing event, were placed into an unused paper bag. Samples were tested at 30-minute and 12-hour intervals. A total of 177 swabs were processed from 30 PPE samples. We found a 6.8% positivity rate among all samples across both collection sites. Highest positivity rates were associated with ventilator disconnection and exposure to respiratory droplets from coughing. Positivity rates differed between hospital units. Total positivity rates were similar between 30-minute (6.7%) and 12-hour (6.9%) sample testing time intervals. Control samples exposed to inactivated SARS-CoV-2 droplets had higher total viral counts than samples exposed to nebulized aerosols. Data suggests paper bags are not a significant fomite risk for SARS-CoV-2 transmission. However, controls demonstrated a risk with droplet exposure. Data can inform guidelines for storing and re-using PPE in situations of limited supplies during future pandemics.