Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review

Delikhoon, Mahdieh; Guzmán, Marcelo I.; Nabizadeh, Ramin; Baghani, Abbas Norouzian

doi:10.3390/ijerph18020395

Cited by 72 publications

(74 citation statements)

References 112 publications

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“…At a relative humidity below 40%, the probability of airborne transmission of SARS-CoV-2 is higher than the humidity of 90% or greater. The persistence of the SARS-CoV-2 at low temperatures (4°C) is signi cant, and at temperatures around 70°C, it can no longer be detected after 5 minutes (Ahlawat et al 2020, Delikhoon et al 2021. The ability of aerosols and small droplets to disperse increases in the atmosphere when the size declines, such that the transmission distance of the aerosols may exceed 2 meters from an infected person (Godri Pollitt et al 2020).…”

Section: Results Of Indoor Air Samplingmentioning

confidence: 99%

Investigating the presence of SARS-CoV-2 on the Surfaces, Fomites, and in Indoor Air of a referral COVID-19 Hospital in a Middle Eastern Area

Gharehchahi

Dehghani

Rafiee

et al. 2021

Preprint

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Coronavirus illness (COVID-19) is an immensely transmissible viral infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This study aimed to assess the presence of SARS-CoV-2 in the indoor air, on the surfaces, and the fomites, and in the indoor air of a COVID-19 referral hospital in Shiraz, Iran. Indoor air sampling was conducted utilizing a standard midget impinger contained 15 ml of viral transfer medium (VTM) equipped with a sampling pump with a flow rate of 10 L min− 1 for 60 minutes. Surfaces and fomites were sampled using sterile polyester swabs. The RNA of SARS-CoV-2 was detected in about 41.2% of indoor air and 32% of swab samples. Four out of the six (66.7%) indoor air samples up to a distance of 2 meters from the patient’s bed in intensive care units (ICU-1, ICU-3), accident and emergency (A&E-2), and negative pressure room were positive for SARS-CoV-2 RNA. All air samples within 2 to 5 meters from the patient’s bed were negative. This study’s results did not support the airborne SARS-CoV-2 transmission; However, it showed contamination of surfaces and fomites in the studied hospital’s wards.

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Section: Results Of Indoor Air Samplingmentioning

confidence: 99%

Investigating the presence of SARS-CoV-2 on the Surfaces, Fomites, and in Indoor Air of a referral COVID-19 Hospital in a Middle Eastern Area

Gharehchahi

Dehghani

Rafiee

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…Indeed, the experiment succeeded in reducing the spread of the airborne epidemic and using high-efficiency particulate air filters to remove 99% of fine air matter because the air change rate is approximately 25 times per hour ( Phoon MBBS, MMed Anaesthesia, FANZCA, MClinUS et al, 2019 ). Delikhoon et al Delikhoon et al, (2021) reviewed the related articles to exactly evaluate the SARS-CoV-2 transmission and the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. The predicted results through the whole review manifested that the airborne transmission of COVID-19 can be bounded indoors with sufficient ventilation through occupied rooms, by routine disinfection of toilets, using negative pressure, using face masks, and maintaining social distancing.…”

Section: The Role Of Hvac Systems In the Spread Of Covid-19mentioning

confidence: 99%

A critical review of heating, ventilation, and air conditioning (HVAC) systems within the context of a global SARS-CoV-2 epidemic

Elsaid

Mohamed

Abdelaziz

et al. 2021

Process Safety and Environmental Protection

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The Coronavirus disease (COVID-19) has spread over the world, resulting in more than 225 million patients, and 4.7 million deaths in September 2021. It also caused panic and terror, halted numerous activities, and resulted in the world economy deteriorates. It altered human behavior and compelled people to alter their lifestyles to avoid infection. Air conditioning systems are one of the most important sectors that must be considered because of the pandemic SARS-CoV-2 all over the world. Air is used as a heat transfer medium in heating, ventilation, and air conditioning (HVAC) systems. The air contains a variety of pollutants, viruses, and bacteria, all of which have an impact on and destroy human life. Significantly in summer, people spend more time in air conditioners which results in lower levels of vitamin D and melatonin which may affect the functioning of their immune system and are susceptible to receiving SARS-CoV-2 from other individuals. As an important component of air conditioning and ventilation systems, the air filter plays a significant role. As a result, researchers must work harder to improve its design to prevent the ultra-small particles loaded with COVID-19. This paper contributes to the design of existing HVAC systems in terms of their suitability and impact on the spread of the hybrid SARS-CoV-2 epidemic, as well as efforts to obtain a highly efficient air filter to remove super-sized particles for protection against epidemic infection. In addition, important guideline recommendations have been extracted to limit the spread of the SARS-CoV-2 throughout the world and to get the highest quality indoor air in air-conditioned places.

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“…These include physical distancing (i.e., keeping 1-2 meters distance from individuals from another household or infected household contacts), the use of face masks in public spaces, cough-, hand- and environmental hygiene measures, and limiting crowding (CDC (2020), RIVM (2021), WHO (2021), Fouda et al, (2021)). While effective at reducing transmission in many settings (Flaxman et al (2020), Delikhoon et al (2021)), the contributions of each non-pharmaceutical measure vary as a result of i) contextual variables, such as poor ventilation, crowding, prolonged durations of stay (Tang et al, 2020), ii) environmental conditions (temperature, humidity), iii) individual variation in infection kinetics, and human behaviours, including singing, shouting, iv) and imperfect adherence to distancing measures and self-isolation methods (Barreda et al, 2020). Understanding how these factors interact and affect the outcomes of NPI’s is important for informed and safe reopening of spaces and a more targeted implementation of interventions .…”

Section: Introductionmentioning

confidence: 99%

The multi-dimensional challenges of controlling respiratory virus transmission in indoor spaces: Insights from the linkage of a microscopic pedestrian simulation and SARS-CoV-2 transmission model

Duives

Chang

Sparnaaij

et al. 2021

Preprint

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Since its introduction in December of 2019, SARS-CoV-2, the virus that causes COVID-19 disease, has rapidly spread across the world. Whilst vaccines are being rolled out, non-pharmaceutical interventions remain the most important tools for mitigating the spread of SARS-CoV-2. Quantifying the impact of these measures as well as determining what settings are prone to instigating (super)spreading events is important for informed and safe reopening of spaces and the targeting of interventions. Mathematical models can help decipher the complex interactions that underlie virus transmission. Currently, most mathematical models developed during the COVID-19 epidemic evaluate interventions at national or subnational levels. Smaller scales of transmission, such as at the level of indoor spaces, have received less attention, despite the central role they play in both transmission and control. Models that do act on this scale use simplified descriptions of human behavior, impeding a valid quantitative analysis of the impact of interventions on transmission in indoor spaces, particularly those that aim for physical distancing. To more accurately predict the transmission of SARS-CoV-2 through a pedestrian environment, we introduce a model that links pedestrian movement and choice dynamics with SARS-CoV-2 spreading models. The objective of this paper is to investigate the spread of SARS-CoV-2 in indoor spaces as it arises from human interactions and assess the relative impact of non-pharmaceutical interventions thereon. We developed a world-wide unique combined Pedestrian Dynamics - Virus Spread model (PeDViS model), which combines insights from pedestrian modelling, epidemiology, and IT-design. In particular, an expert-driven activity assignment model is coupled with the microscopic simulation model (Nomad) and a virus spread model (QVEmod). We first describe the non-linear relationships between the risks of exposure to the virus and the duration, distance, and context of human interactions. We compared virus exposure relative to a benchmark contact (1.5meters for 15 minutes): a threshold often used by public health agencies to determine at risk contacts. We discuss circumstances under which individuals that adhere to common distancing measures may nevertheless be at risk. Specifically, we illustrate the stark increase in exposure at shorter distances, as well as longer contact durations. These risks increase when the infected individual was present in the space before the interaction occurred, as a result of buildup of virus in the environment. The latter is particularly true in poorly ventilated spaces and highlights the importance of good ventilation to prevent potential virus exposure through indirect transmission routes. Combining intervention tools that target different routes of transmission can aid in accumulating impact. We use face masks as an example, which are particularly effective at reducing virus spread that is not affected by ventilation. We then demonstrate the use of PeDViS using a simple restaurant case study, focussing on transmission between guests. In this setting the exposure risk to individuals that are not seated at the same table is limited, but guests seated at nearby tables are estimated to experience exposure risks that surpass that of the benchmark contact. These risks are larger in low ventilation scenarios. Lastly, we illustrate that the impact of intervention measures on the number of new infections heavily depends on the relative efficiency of the direct and indirect transmission routes considered. This uncertainty should be considered when assessing the risks of transmission upon different types of human interactions in indoor spaces. The PeDViS case study shows the multi-dimensionality of SARS-CoV-2 that emerges from the interplay of human behaviour and the spread of respiratory viruses in indoor spaces. A modelling strategy that incorporates this in risk assessments can be an important tool to inform policy makers and citizens. It can empower them to make better design and policy decisions pertaining to the most effective use of measures to limit the spread of SARS-CoV-2 and safely open up indoor spaces.

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Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review

Cited by 72 publications

References 112 publications

Investigating the presence of SARS-CoV-2 on the Surfaces, Fomites, and in Indoor Air of a referral COVID-19 Hospital in a Middle Eastern Area

Investigating the presence of SARS-CoV-2 on the Surfaces, Fomites, and in Indoor Air of a referral COVID-19 Hospital in a Middle Eastern Area

A critical review of heating, ventilation, and air conditioning (HVAC) systems within the context of a global SARS-CoV-2 epidemic

The multi-dimensional challenges of controlling respiratory virus transmission in indoor spaces: Insights from the linkage of a microscopic pedestrian simulation and SARS-CoV-2 transmission model

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