Lecture Notes: Module 1 Introduction to Public Health and Emergency Preparedness PDF

Lecture Notes: Module 1 Introduction to Public Health and Emergency Preparedness Learning Objectives By the end of this module, students will be able to: - Understand the concepts of health and public health - Define health, public health, emergency, emergency manageme...

Lecture Notes: Module 1 Introduction to Public Health and Emergency Preparedness Learning Objectives By the end of this module, students will be able to: - Understand the concepts of health and public health - Define health, public health, emergency, emergency management and public health preparedness - Characterise the three domains of public health - Identify four major ways to measure health - Understand and explain the determinants of health - Discuss public health approaches Introduction Public health is a multidisciplinary subject that concerns the health of a population. Its practitioners, composed of doctors, nurses, pharmacists, lawyers, educators, policymakers and researchers, aim to prevent diseases, promote health and prolong life through the organised efforts of society. This subject draws on a wide variety of disciplines and has developed tools which can allow practitioners to describe, analyse, manage and respond to problems that threaten the health and well-being of a society and community group. This chapter will introduce fundamental principles of public health and their applications to the study and understanding of disasters and medical humanitarian assistance. Basic terminology definitions and theories of public health will also be covered in this chapter. Historical background of how public health is involved in disaster response A brief review of the history of this field of study demonstrates the rapid development of the public health approach to medical disaster and humanitarian response. Although most disasters are natural phenomena, their impact is often defined by human consequences. Historically, major disasters were documented from the perspectives of how human communities might be affected and how systems were destroyed and subsequently improved after these natural calamities. The application of public health principles in studying disasters and their public health and medical humanitarian responses can be useful in mitigating and understanding the human impact of these disasters. Early papers published about the public health impact on disaster management can be dated back to the early 1970s. Results of health surveys related to a tropical cyclone hitting the coast of Bangladesh in 1970 with over 250,000 deaths demonstrated the complicated matrix of needs and risks faced by different stakeholders in disaster situations. The publication highlighted the “value of early on-the-spot assessments” in providing valid and timely data for disaster relief (Sommer & Mosley, 1972, p. 7759). Publications following the Guatemala earthquake that caused an estimated 23,000 deaths in Guatemala illustrated how significant logistical challenges and deficiencies in the international relief system might affect human toll and health outcomes of a natural disaster (de Ville de Goyet, del Cid, Romero, Jeannee, & Lechat, 1976; Spencer et al., 1977). These early examples illustrated the plausible use of disaster research methodology in identifying risk factors associated with specific negative health outcomes linked to the disaster, and hence the possible implementation of effective and targeted interventions as a means of health protection (Glass et al., 1980) (see Case Box 1.1). Concepts of health and public health The World Health Organization has defined health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (Constitution of the World Health Organization, 1946, p. 1). It is important to point out that this definition encompasses a wide range of outcomes from physical, mental and social well-being. It includes both negative and positive aspects of health. It implies that action should aim not only to minimise diseases but also to maximise attainment of potential health. Although this definition has been criticised for over 60 years since its enforcement in 1948, and alternative proposals have been published, it remains the working definition of health internationally. Public health has been defined as “the science and art of preventing disease, prolonging life and promoting health through organised efforts of society” (Acheson, 1988, p. 1; World Health Organization [WHO], 2004, p. 32). Unlike clinical medicine, where physicians and allied health professionals focus on treating diseases and managing the health of individuals, public health professionals focus on optimising the health of populations. The field of public health comprises evidence-based methods, decision-making and the application of theories in society. Effective public health practice is a multidisciplinary effort to make health a priority for all by understanding the determinants of health, addressing health disparities, identifying disease risk factors and implementing preventive strategies. In the context of disaster preparedness, response and management, the definition of health implies the importance of addressing all three fundamental components of health: the physical, social and mental well-being of a population. Although health and medical disaster response programmes tend to focus heavily on safeguarding physical health (e.g. injury management, communicable disease control, food access), an effective health response should consider the mental and social health aspects as well as activities which lead to health improvements instead of focusing only on physical dimensions (see Case Box 1.2). Three Domains of Public Health Public health is a multidisciplinary field in medicine that utilises epidemiology, clinical trials, biostatistics, laws and ethics to protect health, improve health and secure the provision of health services. The various components of public health practice can be grouped into three widely accepted domains of public health: health protection, health improvement and health services (Griffiths, Jewell,& Donnelly, 2005). The three domains of public health illustrate the multidisciplinary nature of this field and its potential applications in the development of evidence-based medical and humanitarian response in disasters. Figure 1.1 shows the anatomy of public health. The three domains include health protection, health improvement and health services, with global health encompassing, and some common tools supporting, all the domains. Health protection involves the prevention, control and response to outbreak of infectious diseases, the regulation of occupational hazards, the monitoring of environmental health hazards, such as air, water and food quality, and response to chemical or technological emergencies (e.g. bioterrorism and radiation disasters). Health improvement involves actions to improve outcomes and health determinants and to reduce health inequalities in a population. This area of work combines different sectors (e.g. housing and education) to ensure that policies and health promotion and education activities at the population level will empower and support individuals to make informed lifestyle choices. Health service and management focuses on the policies and delivery of health services. It promotes evidence-based clinical practices, governance and resource allocation. Of note, the three domains of public health are not mutually exclusive to each other; these subjects overlap and are often interdependent. These domains are commonly applied in general public health practice. Epidemiology, biostatistics, clinical trials, and law and ethics are overlapping public health skill sets that serve as foundation tools for public health practice. They provide common technical approaches to support the knowledge-based domains, as illustrated at the centre of the Venn diagram (Figure 1.1). Epidemiology is the branch of medicine studying the distribution and determinants of health-related states. Biostatistics is the application of statistical techniques to research related to the health field. Clinical trials are a specific type of clinical research that conducts comparisons between treatments/intervention options and serves three major purposes: confirming the safety of treatment, identifying side effects and comparing the effect of a new treatment with the existing standard procedure. This type of research produces evidence-based interventions in disaster response. Law and ethics provide frameworks for decision making. Specifically, public health law is the study of the legal power and hence the duties of the state in providing conditions where people remain healthy. Ethics provides a guiding principle for deciding what is right and wrong. In health care, it is also related to how professionals behave, based on professional bodies’ definition of what is right, fair and just when serving the general community (Griffiths, Jewell, & Donnelly, 2005). In public health- and medical-related disaster studies, epidemiology and biostatistics can provide the technical tools to assess and evaluate the impact and outcomes of disasters. Health policy and service analysis can support service emergency preparedness and training planning, and disaster response management. Health protection actions, such as outbreak and infection control, environmental health assessment and protection, and psychological first aid to support the mental health of responders and affected communities, are important activities to protect the community from the secondary impact of a disaster. Health promotion, nutritional programmes, health risk communication, resource mobilisation and technical capacity building (e.g. human resources development and disaster response team building) might not only support a disaster-affected community but also improve its underlying resilience in its health systems and technical capacity and, ultimately, safeguard the health and well-being of the community. Measuring health There are four major ways to measure health. Firstly, it can be measured by consequences, such as mortality, morbidity, economic implications and so forth. Secondly, it can be assessed by targeting population subgroups. The health impact of an incident toward children, women, older people or those with chronic diseases may vary within the same context. Health outcomes may thus be categorised according to the specific characteristics and needs of each of these subgroups. Thirdly, health might be measured by frequency. Incidence, prevalence, mortality rates and ratios are examples of metrics by which one can quantify health outcomes. Last but not least, disease severity might differentiate a person’s experiences in health. For example, someone who has an early asymptomatic stage of diabetes mellitus might experience a different quality of life when compared with someone who has a severe diabetic condition which requires dialysis or diabetic foot-related amputation. In a disaster, the actual health impact may be difficult to quantify. Available information (e.g. mortality data and hospitalisation information) might allow only a partial overview of the actual health implication of a situation. Figure 1.2 shows that unless specific effort is dedicated to examine the overall real impact of an incident or disaster, most reports provide only a specific and partial perspective toward the true impact. In order to build responsible and evidence-based disaster preparedness and response programmes, it is important to choose the relevant and appropriate metrics to quantify health impacts, assess needs, plan programmes, track intervention programmes and evaluate the effectiveness of activities in a post-disaster context. Determinants of health The socio-ecological approach in public health connotes health is governed by many external factors, not just individual biological make-up or lifestyle choices. This framework proposes that other social, economic, political and environmental factors are all important determinants of health as well, which are the “things that make people healthy or not” (WHO, 2014). Figure 1.3 illustrates the determinants of health organised according to the level of control an individual has over them. At the centre of the diagram are largely non-modifiable biological factors, such as the age, sex and genetic makeup of a person. The second ring beyond the centre includes a person’s individual lifestyle choices, such as dietary habits and activity level. Both the biological and individual lifestyle factors make up the intrapersonal-level determinants, which are mostly within the control of an individual. The third ring includes a person’s social capital, which refers to the social network among which he/she lives, works and interacts. Interpersonal-level determinants involve the impact on health of primary social relationships surrounding an individual, such as friends, family and co-workers. In principle, greater support from families, friends and communities tends to link to better health. In addition, culture, customs and traditions of family and community all impact on the context and how an individual may thrive and live healthily. The fourth ring refers to the wider socio-economic conditions of a person and the society in which he/she resides. Factors including education, work environment, housing and health systems constitute the community/institutional-level determinants that are likely to determine individuals’ material access through income and social status. The outermost ring refers to the general socio-economic, cultural and environmental conditions of the society. Policies, regulations and programmes may affect access to basic services, such as health care and education, and opportunities to thrive socially and economically in society. These are collectively known as macro/public policy-level determinants (McLeroy, Bibeau, Steckler, & Glanz, 1988). In the context of a disaster, although an individual may be free of physical and mental health symptoms, the socio-ecological approach conceptualises health outcomes of individual or population subgroups as varying according to how disaster impacts and alters the various levels of health determinants. For example, a disaster might cause the partial or complete breakdown of transportation networks that limit access to health services. The absence of social services (such as police or fire stations) or the closure of important facilities (such as banks and hospitals) will also pose an indirect impact on health outcomes and general well-being. What Exactly Is an Emergency? Let’s start with the basics. Is an emergency not the same as a disaster? Although these two terms are often used interchangeably they mean something quite different. An emergency can be defined as any event that negatively impacts a community or organisation’s production, safety, or personnel. That’s a wide-open definition that encompasses many events. The caution is to not view an emergency as a disaster. A disaster describes an emergency that has devolved into something with much greater impact. An emergency imposes a negative impact while a disaster’s impact is both negative and severe. By concentrating on disasters, we overlook the more common and often more costly emergencies that affect us all. Disaster planning is fine and quite necessary; however, the purpose of this book is to identify any event that might cause disruption in your life, your community, or your organisation. When we think of disasters, we tend to envision naturally occurring events such as hurricanes and tornadoes. However, emergency preparedness and planning must take into account all emergencies. These include man made emergencies, whether accidental like a chemical spill or deliberate acts such as a terrorist or arson attack. Interestingly, all disasters start out as emergencies. It is not until the event has transpired that the emergency becomes viewed as a disaster. Think about large-scale emergencies such as the Louisiana Flood of May 1995. This single event brought up to twenty inches of rain to New Orleans in a two-day period and caused nearly $350 million dollars in damage (damage total for all of southern Louisiana was more than $7 billion). During the course of the event, it was considered a definite emergency; some people even called it a disaster. However, federal disaster assistance was not available until the president surveyed the damage and declared it a disaster. Compare that with Hurricane Katrina, which slammed into New Orleans a decade later killing almost 1,800 people and causing more than $100 billion in damage. That was an immediate and very obvious disaster. The fact is that emergencies occur much more frequently than do disasters; therefore, an emergency is more likely to affect you or your business. While planning for emergencies, we are encouraged to ask the question: “What is the worst that can happen?” Planning for a worst-case scenario is essential; however, we need to spend quality time performing a true risk analysis by asking, “What events are most likely to happen?” Emergency Management The Federal Emergency Management Agency defines emergency management as the managerial function charged with creating the framework within which communities reduce vulnerability to hazards and cope with disasters. The mission of emergency management is to protect communities by coordinating and integrating all activities necessary to build, sustain, and improve the capability to mitigate against, prepare for, respond to, and recover from threatened or actual natural disasters, acts of terrorism, or other man-made disasters. Public Health Preparedness Public health preparedness, like homeland security, is a term that represents concerns and actions that have occurred throughout history. The term itself, however and the field devoted to thinking about, preparing for, and mobilising resources to respond to public health emergencies is relatively new. The Association of Schools and Programs of Public Health (ASPPH) defined public health preparedness as “a combination of comprehensive planning, infrastructure building, capacity building, communication, training, and evaluation that increase public health response effectiveness and efficiency in response to infectious disease outbreaks, bioterrorism, and emerging health threats.”7(p5) A group at the RAND Corporation, however, proposed a definition in 2007 that is a broader and better characterization of the field: “[P]ublic health emergency preparedness … is the capability of the public health and health care systems, communities, and individuals, to prevent, protect against, quickly respond to, and recover from health emergencies, particularly those whose scale, timing, or unpredictability threatens to overwhelm routine capabilities. Preparedness involves a coordinated and continuous process of planning and implementation that relies on measuring performance and taking corrective action.”8(s9) This definition raises the question: What exactly is a public health emergency? According to the RAND definition, it is an event “whose scale, timing, or unpredictability threatens to overwhelm routine capabilities.” These types of events fit into the following four basic categories: 1. The intentional or accidental release of a chemical, biological, radiological, or nuclear (CBRN) agent 2. Natural epidemics or pandemics, which may involve a novel, emerging infectious disease, a reemerging agent, a previously controlled disease, or occur in areas with limited infrastructure or resources 3. Natural disasters such as hurricanes, earthquakes, floods, or fires 4. Man-made environmental disasters such as oil spills For any of these categories of events to be classified as a public health emergency, it is not just enough for the event to occur, but it also must pose a high probability of large-scale morbidity, mortality, or a risk of future harm. A Trust for America’s Health (TFAH) report refers to public health preparedness as requiring the basic functions of a public health system, such as epidemiology, laboratory capacity, and event-based surveillance capacity.9,10 These core functions need to be supplemented by specialised training, procedures, laws, regulations, and planning, so that all relevant sectors can operate effectively and in a coordinated fashion during a crisis. Doing this well also requires the development of systems for surge capacity, distribution of medical countermeasures, and detecting and managing a response to rapidly mitigate the consequences of the event and move toward recovery. At the global level, the World Health Organization’s Revised International Health Regulations, adopted in 2005, define a public health emergency of international concern (PHEIC) as “[A]n extraordinary event which is determined... to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response.”11 Such an emergency can involve any of the above four types of public health events, as long as it is unusual, unexpected, and has the potential to cross international borders. Some public health concerns that have been called “emergencies” do not meet the criteria of any of the previous definitions. Public health preparedness refers to planning for and responding to acute events, as opposed to chronic conditions that evolve over time. The prevalence of breast cancer, for example, may be a “public health crisis,” but it is not considered an emergency within the purview of public health preparedness. Public health approaches Life-course approach An individual’s behaviour, socio-economic disadvantages and health disadvantages will accumulate over time, creating ever more daunting constraints on a person’s ability to be healthy. Social advantages and health risks will be presented across lifetimes and generations. Thus, the life-course approach takes age into consideration and how past experiences shape future health risks or status. The life-course approach examines the impact of time and human behaviour from both past and present experiences, as well as across generations to identify the current impacts on health. It emphasises how early life intervention shapes health in later life and potentially across generations. Figure 1.4 illustrates how the obstacles to health are passed on from generation to generation. The life-course approach includes two key concepts: first, that intervention in early life is important as it influences the future of one’s health, and second, that different life stages reflect different needs, and therefore require different approaches. Many studies have confirmed the importance of early life intervention. Barker hypothesised that metabolic syndromes in adulthood, such as cardiovascular disease, diabetes mellitus and hypertension, are associated with inadequate nutrition during foetal and infant growth (Barker, 2003). An adult’s mental health may also be related to early trauma (Anda et al., 2006). The Dutch famine provides evidence of undernutrition effects in the period of gestation: babies exposed to famine were lighter, shorter and thinner than unexposed babies (Roseboom et al., 2001; Roseboom, de Rooij, & Painter, 2006). The study also found an association between early undernutrition and the development of diseases in adult life, such as increased risk of chronic heart disease and increased prevalence of obstructive airway disease (Lopuhaa et al., 2000; Roseboom et al., 2000). Different life stages have different needs. Maternal nutritional deprivation in different pregnancy trimesters implies different effects on the in utero growth. Foetal length is mostly gained in the second trimester, while weight is mainly in the third trimester. These concepts have implications for action taken in disaster response. For instance, the nutrition provided for infants, pregnant women, children, adults and the elderly should be adjusted according to their particular needs. The life-course argument proposes important criteria and considerations in prioritisation of intervention in population subgroups in a resources-deficit environment such as that of disaster and humanitarian crisis (see Case Box 1.4). Pathway of care Pathway of care is a concept that illustrates how health needs may be addressed over the span of an individual’s health journey for a condition or a disease. As shown in Figure 1.5, for any health-related risk or condition, an individual will begin by experiencing activities/interventions that address “health protection”, “disease prevention” and “health promotion” to try to keep him/her free from diseases. His/ her disease or health experiences will then be followed by diagnosis, treatment and rehabilitation, and finally palliative care if he/she is in the terminal stage of a disease. In public health, an emphasis on prevention in all aspects of the pathway of care model will demonstrate how comprehensive health care services might be possible even under limited resources. It is important to highlight once again that the management of medical conditions involves a spectrum of services that range from disease prevention/protection to health promotion, diagnosis, treatment, rehabilitation and palliative care. Heath responses after a disaster will focus on diagnosis and treatment of clinical conditions. Medical relief groups and health respondents who might have limited technical capacity and resources could consider technical knowledge transfer and community capacity training of local staff so as to ensure the possibility of clinical case follow-up. Community partnerships and collaborations that promote local ownership and technical transfer would be essential for the sustainability of service beyond the disaster relief period. Even if medical and health relief programmes do not include the provision of chronic disease treatment, agencies could consider: (1) providing health education and promotion information that are relevant to protect patients with knowledge to enhance well-being and to reduce potential disease complications, (2) identifying potential referral where relevant services and clinical management support may be provided,(3) facilitating referral with good clinical record keeping, and (4) coordinating with other domains of relief services (e.g. food and nutrition-based assistance groups to provide a nutritionally appropriate diet for a medical disease affected population, such as a low-salt, low-sugar diet) to minimise avoidable clinical disease complications. At the very least, relief groups and respondents might consider documenting the key disease burdens among the disaster-affected population so as to highlight health gaps that need to be addressed in the post-disaster rebuilding phase. Hierarchy of prevention There are three levels of health prevention – namely primary, secondary and tertiary (Leavell & Clark, 1958). Primary prevention concerns measures that prevent the onset of disease. Strategies may include health protection and health promotion. Health protection can be carried out through the establishment of health policies, regulations and vaccinations, while health promotion mainly involves health education. Secondary prevention refers to stopping the progression of disease after it occurs. It aims to detect disease early, thus increasing the opportunity for intervention to prevent its progression and the emergence of symptoms. Screening is one classic example of secondary prevention. Tertiary prevention focuses on the rehabilitation of patients with an established disease to minimise residual disabilities and complications. It aims to restore bodily functions that have been impaired by the disease. Services in this category include treatment, rehabilitation and palliative care. The application of these prevention concepts in establishing disaster mitigation strategies, response programmes and post-disaster recovery policies may enhance individual survival and protect communities from adverse health outcomes in natural disasters (Leavell & Clark, 1958; Hong Kong Special Administrative Region [HKSAR], 2008). Figure 1.6 displays the hierarchy of prevention related to disasters. In disasters, primary prevention is at the lowest level of the pyramid, covering the largest proportion of preventable health impact. This is because primary prevention is targeted at the wider community. Secondary prevention is targeted at smaller populations which are affected by the disaster. Tertiary prevention focuses only on people who have already sustained the health impact of the disaster, which constitute a small portion of the affected population.