����������������������������M.S.S. in Health Economics�HE 604: Public Health and Epidemiology (PHE)�Outbreak and Emergency Management in �Public Health�

Dr. Aninda Nishat Moitry

MBBS, MPH, MSc (Epi), FRSPH

08 June 2023

Overview

• Introduction to outbreak investigation
• Steps of outbreak investigation
• Public Health emergency management

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Let’s begin with some definitions

• Endemics: AN ENDEMIC is something that belongs to a particular people or country
• Refers to the constant presence and/or usual presence of a disease or infectious agent in a population within a geographic area
• Sporadic refers to a disease that occurs infrequently and irregularly
• Hyperendemic refers to persistent, high levels of disease occurrence
• Epidemic: AN EPIDEMIC is a disease that affects a large number of people within a community, population, or region
• CDC describes an epidemic as an unexpected increase in the number of disease cases in a specific geographical area: Yellow fever, smallpox, measles, and polio are prime examples
• An epidemic disease doesn't necessarily have to be contagious, e.g., West Nile fever and the rapid increase in obesity rates are also considered epidemics
• Epidemics can refer to a disease or other specific health-related behavior (e.g., smoking) with rates that are clearly above the expected occurrence in a community or region
• Pandemic: A PANDEMIC is an epidemic that’s spread over multiple countries or continents
• WHO declares a pandemic when a disease’s growth is exponential, the growth rate skyrockets, and each day cases grow more than the day prior
• In being declared a pandemic, the virus has nothing to do with virology, population immunity, or disease severity; it means a virus covers a wide area, affecting several countries and populations

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What is an outbreak?

• AN OUTBREAK is a greater-than-anticipated increase in the number of endemic cases
• It can also be a single case in a new area
• If it’s not quickly controlled, an outbreak can become an epidemic

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Causes of Disease Outbreaks

• Several factors contribute to the outbreak of infectious diseases.
• Contraction can occur as a result of transmission from people, animals, or even the environment. For example:
• Weather conditions: e.g., whooping cough occurs in spring, whereas measles tend to appear in the winter season
• Exposure to chemicals or radioactive materials: e.g., Minamata is a disease contracted after exposure to mercury
• The social aftermath of disasters: such as storms, earthquakes, and droughts can lead to high disease transmission
• A number of environmental factors: such as water supply, food, air quality, and sanitation facilities can catalyze the spread of infectious diseases

Disease origins

• Can also be unknown
• These kinds of diseases could be caused by a variety of factors, including:
• A new or newly modified pathogen
• Natural toxins
• Undetected chemical releases
• Unknown ionizing radiation over-exposure

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Steps of an Outbreak Investigation

Step 1:  Prepare for field work

• The preparations can be grouped into two broad categories: 

     (a) Scientific and investigative issues, and

     (b) management and operational issues

• Good preparation in both categories is needed to facilitate a smooth field experience

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Step 2 : Establish the existence of an outbreak

• An outbreak or an epidemic is the occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time
• Usually, the cases are presumed to have a common cause or to be related to one another in some way

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Step 3: Verify the diagnosis

•  The next step, verifying the diagnosis which is important: 

   (a) To ensure that the disease has been properly identified and

   (b) To rule out laboratory error as the basis for the increase in reported cases

Step 4: Construct a working case definition

• A case definition is a standard set of criteria for deciding whether an individual should be classified as having the health condition of interest
• A case definition includes clinical criteria and particularly in the setting of an outbreak investigation restrictions by time, place, and person

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Step 5: Find cases systematically and record information

• Many outbreaks are brought to the attention of health authorities by concerned healthcare providers or citizens
• So, the first effort to identify cases is directed at healthcare practitioners and facilities — physicians’ clinics, hospitals, and laboratories
• Alternatively, it should conduct active surveillance by telephoning or visiting the facilities to collect information on any additional cases

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Step 6: Perform descriptive epidemiology

• Conceptually, the next step after identifying and gathering basic information on the persons with the disease is to systematically describe some of the key characteristics of those persons
• This process, in which the outbreak is characterized by time, place, and person, is called descriptive epidemiology

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Step 7: Develop hypotheses

• In an outbreak context, hypotheses are generated in a variety of ways
• First, consider what you know about the disease itself:
• What is the agent’s usual reservoir?
• How is it usually transmitted?
• What vehicles are commonly implicated?
• What are the known risk factors?
• In other words, by being familiar with the disease, you can, at the very least, “round up the usual suspects”
• Another useful way to generate hypotheses is to talk to a few of the case-patients
• The conversations about possible exposures should be open-ended and wide-ranging, not necessarily confined to the known sources and vehicles

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Step 8: Evaluate hypotheses epidemiologically

• After a hypothesis that might explain an outbreak has been developed, the next step is to evaluate the plausibility of that hypothesis
• Typically, hypotheses in a field investigation are evaluated using a combination of environmental evidence, laboratory science, and epidemiology

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Step 9: Reconsider, refine, & re-evaluate hypotheses

• When an outbreak occurs, whether it is routine or unusual, consider what questions remain unanswered about that particular disease and what kind of study you might do in this setting to answer some of those questions
• The circumstances may allow you to learn more about the disease, its modes of transmission, the characteristics of the agent, host factors, and the like
• Even when an analytic study identifies an association between an exposure and disease, the hypothesis may need to be honed
• Sometimes a more specific control group is needed to test a more specific hypothesis

Step 10: Compare & reconcile with laboratory &/or environmental studies

• While epidemiology can implicate vehicles and guide appropriate public health action, laboratory evidence can confirm the findings
• Environmental studies are equally important in some settings, they are often helpful in explaining why an outbreak occurred
• While you may not be an expert in these other areas, you can help
• Use a camera to photograph working or environmental conditions
• Coordinate with the laboratory, and bring back physical evidence to be analyzed

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Step 11: Implement control and prevention measures

• In most outbreak investigations, the primary goal is control of the outbreak and prevention of additional cases where confidentiality is an important issue in implementing control measures
• In practice control and prevention activities should be implemented as early as possible
• The health department’s first responsibility is to protect the public’s health, so if appropriate control measures are known and available, they should be initiated even before an epidemiologic investigation is launched
• For example, a child with measles in a community with other susceptible children may prompt a vaccination campaign before an investigation of how that child became infected
• Confidentiality is an important issue in implementing control measures: Healthcare workers need to be aware of the confidentiality issues relevant to collection, management and sharing of data
• In general, control measures are usually directed against one or more segments in the chain of transmission (agent, source, mode of transmission, portal of entry, or host) that are susceptible to intervention

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Step 12: Initiate or maintain surveillance

• Once control and prevention measures have been implemented, they must continue to be monitored
• If surveillance has not been ongoing, now is the time to initiate active surveillance
• If active surveillance was initiated as part of case finding efforts, it should be continued

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Step 13: Communicate findings

• The final task is to summarize the investigation, its findings, and its outcome in a report, and to communicate this report in an effective manner
• This communication usually takes two forms:

i. An oral briefing for local authorities

• If the field investigator is responsible for the epidemiology but not disease control, then the oral briefing should be attended by the local health authorities and persons responsible for implementing control and prevention measures
• Often these persons are not epidemiologists, so findings must be presented in clear and convincing fashion with appropriate and justifiable recommendations for action

ii. A written report

• Investigators should also prepare a written report that follows the usual scientific format of introduction, background, methods, results, discussion, and recommendations
• By formally presenting recommendations, the report provides a blueprint for action
• It also serves as a record of performance and a document for potential legal issues. It serves as a reference if the health department encounters a similar situation in the future
• Finally, a report that finds its way into the public health literature serves the broader purpose of contributing to the knowledge base of epidemiology and public health

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Public Health Emergency Management (PHEM)

The Emergency Management Cycle

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1. Focuses on reducing hazard losses or risk and controlling anticipated damage; activities in this phase can be carried out before, during, or after an event

2. Activities occur before an event and center on building or maintaining staff, systems, and infrastructure capacity as well as carrying out the planning, training, and exercising necessary to identify gaps and improve emergency response capabilities

4. Phase occurs during and after the response and encompasses efforts to return or adapt to “new” normal conditions after an event

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3. In the emergency management cycle occurs in recognition of a hazard that threatens to overwhelm day-to-day functions or capacities

Standards

• We define standards as codified expectations for practice, typically in the form of guidelines or requirements for functions, processes, resources, or performance in an organization or system
• Standards serve multiple purposes like:
• Hazard and risk assessment,
• Planning,
• Prevention and mitigation,
• Incident management,
• Resource management,
• Communications,
• Operations, and
• Training, exercising, evaluation, and corrective action and quality improvement

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Incident Management Systems

According to the National Response Framework describes key contributions of an IMS in a response context, including

•  Developing a single set of objectives, 
•  Using a collective, strategic approach, 
• Improving information flow and coordination, 
•  Creating a common understanding of joint priorities and limitations,
•  Ensuring that no agency’s legal authorities are compromised or neglected, and
•  Optimizing the combined efforts of all participants under a single plan

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Emergency Management in a Global Context

• Internationally, PHEM is becoming a more prominent fixture in global health initiatives
• In 2005 the revised International Health Regulations provided a framework for member countries to better protect their populations from public health threats and emphasized the need for emergency preparedness and response activities to meet their obligations
• The Global Health Security Agenda launched in 2014 expanded on International Health Regulations (2005) by strengthening national public health EOCs among other elements of PHEM

Where Do We Go From Here?

• A spate of recent global disease outbreaks serves as a reminder of the importance of developing and maintaining capacities to effectively manage responses to public health emergencies
• The future of PHEM as a field of practice is difficult to predict, but its maturation may hinge in part on at least 2 factors:
• The first factor relates to the need for evidence: Prominent public health programs in areas such as infectious and chronic disease surveillance and prevention depend on high-quality data and evidence of effectiveness
• The second factor relates to instruction and pedagogy: Whether and to what extent PHEM will further cohere as a field of practice will depend on how its core precepts and practices are imparted to entering practitioner cohorts

Thank You