Epidemic Risk Analysis and Assessment in Transport Services

COVID-19 and Other Viruses

Rafał Burdzik

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000455328
• Edition: 1
• Topic: Medicina
• Subtopic: Epidemiologia

"Accurate and fully explicit mathematical models and derivations make the proposed method truly universal irrespective of the geographical location and the kind of virus epidemic."

Minvydas Ragulskis, Kaunas University of Technology, Lithuania

The effects of a pandemic on public, personal and freight transport can be sudden and massive, and yet transport is vital to the functioning of an advanced economy and society. On the other hand, transport, due to social mobility, has a decisive influence on the speed and scope of epidemic spread. This book presents a complete methodology for assessing the hazards, and probability and risks of viral transmission on transport services, using as a detailed example the SARS-CoV-2 coronavirus pandemic. It gives proposals and recommendations for estimating human deaths caused by virus infection in transport. Significantly, it considers not only passenger transport but also freight transport, such as delivery or parcel services. The tools include a matrix of hazard assessment in various transportation services, with a methodology for estimating the probability of virus transmission through both droplets and surface contact. These allow estimation of the effects of infections and consequent epidemic risk in all kinds of transport services, including freight, and provide methods for forecasting and risk management which determine transport safety.

Rafa? Burdzik is a professor in the Faculty of Transport and Aviation Engineering at Silesian University of Technology, Poland, with more than 20 years of transport research experience.

Chapter 1

Introduction

1.1 Pandemic Threats in Transport, the Present and the Future

The global pandemic and the resulting epidemic threats of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may directly cause the coronavirus disease 2019 (COVID-19), display characteristics of a global crisis that affects absolutely all areas of human activity and human existence. Population movements within and between regions and countries play a key role in seeding the virus outbreaks and accelerating the COVID-19 spread (Simiao Chen et al., 2020; Tian et al., 2020).

Transport, which is perceived as not only the bloodstream of the world economy but also the foundation of human mobility and very often the manifestation of freedom, has also been affected by the global pandemic. One of the most critical challenges facing transport was the imbalance in global supply chains, associated with the economic and trade stability at the local, national and continental levels. Supply chain problems were obviously also caused by production downtime, drastic changes in the product demand structure and political decisions. Another sphere of the crisis in transport is passenger transport, especially collective public transport. This socially relevant transport sector, which has always required balance and compromise between financial result and mobility, and urban mobility in particular, as well as a sustainable transport policy in terms of minimising the negative environmental impact as opposed to individual transport, has faced new challenges. Attempts to sustain the image of an epidemically safe public transport and to comply with the restrictions imposed by state governments often boiled down to reducing the number of travellers in the means of collective public transport, for example, to 50% (or even 30%) of capacity. However, it is difficult to find a methodological, mathematical or sanitary basis for determining such safety measures.

In the author’s opinion, there are numerous and very serious problems of the transport sector and transport services which, in this case, result from the lack of a methodical approach to the problem of epidemic threats, including infection in an epidemic of global reach, all the more so since the current SARS-CoV-2 pandemic is a phenomenon that has never been seen before, and the effects of COVID-19 and the related death rate make it necessary to adopt new measures and scales of epidemic hazard, even if compared to the Spanish flu pandemic of 1918–1920, which was also global and its mortality rate was claimed to be higher, as extremely divergent sources provide, ranging between 21.5 million (Jordan, 1927) and as much as 100 million (Johnson and Mueller, 2002) people. The circumstances of the spread of an epidemic should be taken into account. In 1918–1920, during the First World War, the disease encountered perfect conditions for spreading. There were virtually no hygienic and sanitary rules in place, soldiers at the front line stayed in close proximity in trenches under extreme conditions of exhaustion and lack of strength, additionally deprived of medical aid. Today, the situation is completely different, and so is people’s awareness and available means of personal hygiene, a wide range of effective drugs and medical aids for improving immunity, as well as prevention. So why, given such disparate conditions, has the SARS-CoV-2 epidemic been developing so dynamically? The answer seems to be mobility, i.e. the ability to move large groups of people in a short time over very long distances. Hence, the enormous pace of the coronavirus spread, which poses such a huge global threat.

Therefore, the author decided to address the issue of the coronavirus pandemic in transport services in a methodical manner. He decided to develop a dedicated proprietary methodology for identification and assessment of epidemic hazards in the implementation of transport services based on the risk management methodology. In addition to the assumed effects of the methodology developed, it seems very important to use it to limit the spread of the coronavirus through transport processes, for purposes of identifying risk factors, selecting security systems and deciding on the method assumed to enable provision of transport services.

People are exposed to viruses in everyday activities, also in different transport processes. Coronavirus transmission is classified under two main categories: airborne virus transmission in droplets exhaled and surface transmission of viruses deposited on touch surfaces from either exhalations or hand contact (Garciá De Abajo et al., 2020). An important and fundamental input to the study of the SARS-CoV-2 transmission problem in transport has been provided in the studies by Smieszek (2009), Smieszek et al. (2009) and Smieszek et al. (2019). These papers describe a formula which models transmission probabilities based on mechanistic considerations, the actual amount of infectious organisms ingested by an individual according to the Poisson probability distribution (Smieszek, 2009), models of epidemics based on the random mixing model without repetition of contacts, the Susceptible, Infectious or Recovered (SIR) model (Smieszek et al., 2009) and aerosol transmission perceived as a major contributor to the spread of influenza (Smieszek et al., 2019).

An interesting approach has been presented by Ng et al. (2020), represented by two risk prediction models for determining COVID-19 positive patients. The effect of each predictor in the model was converted into a score and summation of all predictors that can be mapped to an estimated risk of being COVID-19 positive. A total of 1,330 patients with and without COVID-19 from 4 Hong Kong hospitals were included in the survey.

Given the fact that infected people can travel worldwide and transmit the virus to remote locations, the issue of the epidemic hazard assessment in transport services has become extremely important. Additionally, the conditions of confined spaces typical of means of transport necessitate a short distance between passengers, which may consequently boost virus transmissions. There are five main mechanisms for the transmission and spread of microorganisms: direct contact, fomites, aerosol (airborne), oral (ingestion) and vectorborne. Droplet and airborne mechanisms probably represent the greatest risk for passengers using means of transport.

The study by Mangili and Gendreau (2005) emphasises that, prior to 2002, data from epidemiological studies indicated that the risk of transmitting the disease to other asymptomatic passengers in an aircraft cabin was associated with contagious passengers sitting in two rows for a flight time exceeding 8 hours. These conclusions were based on studies of in-flight spread of tuberculosis, which were considered representative of other airborne infectious diseases. However, a study of the SARS-CoV-1 virus behaviour in 2002 revealed significant differences. In that case, infection was found in passengers sitting up to seven rows away from the host passenger.

With regard to the SARS-CoV-2 epidemic, i.e. the coronavirus, which is characterised by even greater transmission capacity and environmental resistance, the associated threats have become unimaginably greater.

An attempt to address issues related to risk assessment vis-à-vis coronavirus infection in air transport was made by Schultz and Fuchte (2020). The problem of evaluation of aircraft boarding scenarios considering reduced transmission risks was studied. Schultz and Fuchte (2020) implemented a transmission model in a virtual aircraft environment to evaluate individual interactions between passengers during aircraft boarding and deboarding.

If one comes across any scientific papers on the epidemic risk assessment in transport, they are based on virus propagation simulation models or data from epidemic studies. Risk assessment incorporating epidemiological data into mathematical models may reveal the factors of transmission (e.g. ventilation effects). In the study addressed by Ko et al. (2004), the risk of tuberculosis transmission on board a typical airliner was analysed using a simple one box model and a sequential box model.

Opinions on this matter vary to a considerable extent. International Air Transport Association (IATA), in contrast, states that 1,100 infected people flying have been traced and no secondary cases have been identified. The reasons for this phenomenon are said to be connected with air circulation and are explained as follows: the aircraft cabin airflow is downward, the air inside aircraft cabins is exchanged frequently, recirculated air flows through high-efficiency particulate air (HEPA) filters, and the air is quite dry at the cruising altitude. But there are apparently no data that would substantiate such a statement, especially if one should consider other research projects (Olsen et al., 2003; Mangili and Gendreau, 2005). A study on the SARS transmission during the Amoy Gardens outbreak in Hong Kong reported that a total of 40 flights were investigated for carrying SARS-infected passengers. Five of these flights were suspected of probable on-board transmission of SARS in 37 passengers (a 3-hour flight carrying 120 passengers on 15 March 2003). It began a super spreading event, which may account for 22 of the 37 cases of persons who contracted SARS after travelling by air. Laboratory-confirmed SARS coronavirus infection occurred in further 16 persons. The number of secondary cases attributable to that flight remains under investigation, but more than 300 people might have been affected. It should be underscored once again that the current SARS-CoV-2 virus is transmitted much more easily and its environmental resistance is higher.

In this case, the transport sector and transport services have faced very serious problems, which result from the lack of a methodical approach to the problem of epidemic hazards, including infection in a global epidemic, all the more so since the current SARS-CoV-2 pandemic is a completely unprecedented phenomenon, and the effects of COVID-19 as well as the related death rates make it necessary to adopt new measures and scales of epidemic hazard. Therefore, the author decided to address the problem of the coronavirus pandemic in transport services methodically. He decided to develop a dedicated proprietary methodology for identification and assessment of the epidemic hazards attributable to the implementation of transport services based on the risk management methodology.

Chapter 2

Risk Management in Transport

2.1 Risk Management Objectives: Epidemic Threats in Transport

Risk assessment is the cornerstone of the worldwide approach to prevention of occupational accidents and ill health. The most important piece of European legislation relevant to risk assessment is Framework Directive 89/391, which has been transposed into national legislation.

The purpose of risk assessment is to allow for the measures that are necessary for safety and health protection to be undertaken. These measures include:

• prevention of risks,
• providing information about hazards,
• providing training to workers,
• providing the organisation and means to implement the necessary measures.

While the purpose of risk assessment includes prevention of risks, which should always be its goal, it will not always be achievable in practice. Where elimination of risks is not possible, the risks should be reduced and the residual risk should be controlled.

Hazard, as any source of potential harm or adverse health effects, can be caused by anything – whether a piece of equipment, operations or processes, work methods or practices. The definition of risk provided by the ISO 31000:2009 standard is an effect of uncertainty on the objectives. The ISO 31000 definition of risk shifts emphasis from past preoccupations with the possibility of an event to the possibility of an effect and, in particular, an effect on the objectives (Purdy, 2010). ISO 31010:2009 also describes risk assessment techniques. The latest revision of ISO 31000, Risk management – Guidelines, was published in 2018. Following are the main changes introduced since the previous edition:

• review of the principles of risk management, which are the key criteria for its success,
• focus on leadership by top management,
• greater emphasis on the iterative nature of risk management, drawing on new experiences, knowledge and analysis for the revision of process elements, actions and controls at each stage of the process,
• streamlining of the content with greater focus on sustaining an open systems model that regularly exchanges feedback with its external environment to fit multiple needs and contexts.

These changes led to a revision of the ISO 31000 model which represents principles, the framework and the process, as shown in the Figure 2.1.

Figure 2.1Risk management principles, framework and process, based on ISO 31000:2009.

The risk management process involves systematic application of policies, procedures and practices to the activities involved in communicating and consulting, establishing the context and assessing, treating, monitoring, reviewing, recording and reporting risk.

Generally speaking, risk estimation methods can be divided into three groups:

• quantitative,
• qualitative,
• mixed.

The quantitative methods are based on predefined measures which determine the probability of the occurrence of hazards as well as the effects thereof. When using properly defined measures and scales, one can treat these methods as objective and repeatable in assessment. An example of a quantitative method is the Events Tree Analysis (ETA), which consists in analysing the consequences resulting from specific events. What follows is the isolation of the triggering event on the basis of which the probable sequences of events are established. In this case, the probability score is the product of the probabilities of all sequences of events. Another example is the Faults Tree Analysis (FTA) method. In contrast to the ETA method, the fault tree in this method is created by starting from the consequences, whereupon they are identified by moving in the direction of the preceding events.

Qualitative methods are based on individual risk estimation using subjective measures. The correctness of inferring from this group of methods is strongly determined by the expertise of the person conducting the assessment. This poses a considerable risk for the application of these methods and contributes to t...