What Is an Outbreak Investigation Report?

An outbreak investigation report is a document that combines an outbreak report and an investigation report. By definition, an outbreak report is a record that describes the events of the outbreak after its completion. It summarizes the beginning of the situation and detection, the processes of conducting investigations, identified and observed control interventions, and details on descriptive epidemiology and outcomes. It is also a beneficial tool for conducting risk analysis to identify emerging hazards and open possibilities for investigation and intervention techniques. Outbreak investigation reports rangers from 2000 to 2500 words, excluding appendices, abstracts, tables, references, and additional documents. It is necessary to conduct this report to support future investigations and prevent insurmountable outbreaks.

From the live tally coming from the Statista website regarding the Coronavirus (COVID-19) pandemic, as of October 1, 2021, the total number of COVID-19 cases worldwide already reached monstrous levels at an estimate of 234,608,477 individuals. Numbers continue to rise because of various strains from different countries. However, a vast majority of the population already has protection from the virus through continuous vaccinations. With the general population getting vaccines, it can help lessen the spread to more people.

Types of Outbreaks

Outbreaks are often categorized based on the manner they spread through different populations. There are various classifications for them, including common-source that splits into sub-categories: point, continuous, and intermittent. There are also propagated, mixed, and other categories. Below are the types of outbreaks together with their definitions.

Common-source outbreak: The outbreak happens when there is a commonality of cases that originates from a single source. Point source outbreak is a sub-category where the source and infected cases stem from an individual location within a short period. In these situations, the source comes from an area at a single point in time and place. Most of these outbreaks have a bell-shaped curve on a line graph, increasing sharply at one point and declines the next. The graph represents the normal distribution of the incubation period of the causative agent. The epidemic curve of the point source outbreak help distinguish instances of transmission. A continuous source outbreak refers to cases stemming from a singular location for extended periods. The form of these curves tends to plateau over time until the removal of the source of the outbreak. When it comes to an intermittent source outbreak, the epidemic curve has a pattern that reflects the intermittent nature of exposure.Propagated outbreak: A propagated outbreak results from the disease transmission from one individual to another. The method of transmitting infections is through direct person-to-person contact. When it comes to propagated outbreaks, cases transpire for more than a single incubation period. The epidemic usually subsides over prolonged periods, usually over generations. It happens due to the expiration level of susceptible persons harboring the infection or the effectiveness of intervention measures. A relevant example of a propagated outbreak is measles.Mixed epidemics: Some epidemics feature elements of common-source and propagated outbreaks. Mixed epidemics is a general model originating from a common-source outbreak that extends to a propagated outbreak through person-to-person transmissions. Other outbreaks: There are instances when epidemics start neither through common-source, propagated, or both. Some outbreaks originate from zoonotic or vector-borne diseases resulting from the prevalence of infection in the host species. Other facts that affect these outbreaks are the presence of vectors and the interaction between host and vector.

The Structure of an Outbreak Investigation Report

The composition of an outbreak investigation report shares similarities with other investigation reports. The article presents the components of an outbreak investigation report with their corresponding descriptions to guarantee that the document you have contains all the essential details.

Summary or abstract: The abstract of the report presents the key points of an outbreak, and answers questions about the affected population, root cause of the pandemic, the date and location of its origin, and the process of emergence. There must be an emphasis on the crucial lessons and list all necessary recommendations. The summary also highlights an effective action plan to control and prevent future outbreaks and create further contingency plans. The information must be present in the general report. Introduction and background: The introduction contains information that assists readers in understanding the context and background of the epidemic. Content including population demographics, surveillance data, similar outbreaks, site descriptions, healthcare systems, and essential industries must be visible in this section. Outbreak Description: It starts with detailing the initial situation of the outbreak, including its initial reporting, immediate response, and current facts about it. It must also mention investigation procedures and objectives, register the factors and sources of the pandemic with knowledge of the extent of its negative effects. It also contains outbreak management responses, including details about the outbreak management teams and control measures.Methods: The method section supplies the components to comprehend the methodical responses to investigate and control the outbreak. Epidemiological processes include case definition and finding, study design and population, comparison groups, exposures of interest, sampling and sampling size, data collection, analysis plan, and statistical test. Laboratory information details clinical and environmental specimens, while environmental studies focus on risk assessments and site visits.Results: The result section contains the necessary findings leading to the conclusion. The results must be consistent with the included methods in the report to remain factual and accurate. Refrain from including explanations and discussion in the section and must mainly consist of data graphs, charts, tables, and other visual representations. Information including response rates, epidemic curve, mode of transmission, number of cases, molecular results, and other related data.Discussion: The section provides a clear interpretation of the results. The facts must have a connection with the context of the outbreak, methodologies, and limitations. The structure must focus on the result summary, findings, main problem, and study inferences. The conclusion must have clear and logical interpretations, approval or disapproval of the hypothesis, and actions taken for well-being.Lessons learned: Stemming from the investigations and experiences of the outbreak, there must be a clear outline of relevant problems and suggestions for improvement. These insights are necessary to agencies and establishments facing similar approaches, methods, tools, and plans of prevention in the future.Recommendations: The recommendation section must present specifications on the process to control and prevent outbreaks. It must also present advice on improving management and methods of investigation in the future. The section must be short, concise, specific, targeted, and realistic.References: The report includes facts and information indirectly linked to it. The reference format allows the readers to source the original documents.Annexes: Annexes cover vital tools to collect data and inform readers of the performed work during the investigation. Documents present in the section include series of events, outbreak control team, detailed results, relevant questionnaires, information letters, and press releases.

The Process of an Outbreak Investigation

There are necessary steps that individuals take to guarantee their reports possess accurate and factual results when it comes to an investigation surrounding the health and safety of the public. Below is a guide that helps individuals process outbreak investigations.

Step 1: Verify Diagnosis and Confirm the Outbreak

The first step into outbreak investigation is to verify the diagnosis and confirm the outbreak officially exists. Gather relevant and factual information that relates to the origin of the pandemic. Identify associated symptoms that lead to contracting the disease from initial findings from exposed individuals. As much as possible, investigators must travel to the point of origin where the outbreak started.

Step 2: Define the Case and Conduct Case Findings

The case description with the exclusion criteria can be straightforward or complex, depending on the serotype or causative agent of the outbreak. In many outbreak investigations, multiple case descriptions exist depending on the data files present after initial diagnosis. The data results follow a comprehensive analysis through different case descriptions. However, if the number of cases available does not contain limiting factors and is a controlled study that examines risk factors, there must be a strict case definition to increase specificity and reduce misclassifications.

Step 3: Tabulate and Orient the Information

To pinpoint the who, how, and when of the outbreak, it is beneficial to produce visual representations to readers. It must show demographics about the age, gender, and location of each patient. By plotting significant cases on a map, you can determine the origin of the outbreak. Once the investigators discover the cause of the pandemic, they can now classify the type and make the necessary countermeasures to lessen and prevent its spread.

Step 4: Formulate and Test the Hypothesis

The source and route of exposure explain the occurrence of the outbreak. While the accurate source of the spread comes from a short list of possibilities, there is still a need to investigate and formulate a hypothesis. A review of epidemiological, microbiological, and veterinary data is useful to learn about known and suspected sources of the previous outbreak with similarities to the current one. In testing the hypothesis, considerations about the analytic epidemiologic study must always be possible. Considering various case study methods is necessary to get the most accurate results for the investigation.

Step 5: Implement and Evaluate Control Measures

When it comes to the prevention of illnesses, there are different measures investigators must consider. Control measures include transmission prevention by medical practitioners, patient isolation, proper disposal of waste, isolation of possible and suspected individuals, mass vaccination, and herd immunity.

Step 6: Communicate Finding to the General Public

Once the entire process undergoes verification and completion, all associated findings to the pandemic must be available to the public. Initially, the results must first be presented to medical professionals and practitioners, then to government officials to transmit the necessary information to the population. The final step ensures the society receives factual and accurate data from experts to prevent or lessen the transmission of disease.


What are the basic components of an outbreak investigation?

According to the Centers for Disease Control and Prevention, the essentials of an outbreak investigation consists of establishing case definitions, confirming cases are real, establishing the background rate of disease, defining the scope of the outbreak, examining epidemiologic features, generating and testing hypothesis, collecting and testing environmental samples, performing control measures, and informing the public.

How do you confirm the existence of an outbreak?

One of the ways health officials determine the occurrence of outbreaks is through public health surveillance. The process is through routinely gathering reports of illnesses to identify the types of disease and the location where it will emerge. If the infection happens within a large population surpassing the estimated number, it is a cluster. If the people in a cluster manifest similarities in contracting the illness, it is an outbreak.

What is the importance of outbreak investigations?

The principal purpose of an outbreak investigation is to determine the cause of an outbreak. Knowing the origin of the disease aids in controlling and preventing the spread of the illness. Utilizing lessons from these investigations helps generate useful recommendations to restrict similar outbreaks in the future. Without the presence of an outbreak investigation, it becomes impossible to find the cause of a pandemic.

Outbreak investigation reports help the public to understand the conditions of a pandemic. Without it, relayed knowledge about diseases and illnesses can stem from false information to discourage individuals from making the right decisions to prevention and safety. To protect the people around us, it pays to get factual and accurate data backed up by experts to control the spread of the outbreak. From the article above, outbreak investigation report samples are available for use and download. Use them to inform future generations to limit the circumstances of pandemics.