EPIDEMIOLOGICAL SURVEILLANCE: COMPONENTS, TYPES AND IMPORTANCE - MEDICINE - 2025

The epidemiological surveillance is an ongoing process of research, evaluation and control of public health. It involves the collection of epidemiological data for its analysis and interpretation and the dissemination of information. In addition, it serves as the basis for designing short-term and long-term strategies to combat infectious diseases.

Such a process of periodic surveillance allows the public bodies in charge of health to make important decisions about existing diseases or possible threats to public health. For its effectiveness, epidemiological surveillance must be integrated into macro prevention plans.

Through epidemiological surveillance, it is possible to identify and prevent the spread of cases of dangerous diseases or events, such as epidemics, outbreaks of infectious diseases, cases of poisoning by pesticides and other poisons.

For the full fulfillment of the epidemiological surveillance function of the state, it is necessary to have a network at all levels of care. This network must be properly structured and trained.

Only in this way is it possible to detect, evaluate, verify and analyze data, and then notify the authorities and launch preventive information campaigns. In addition, it is a first-hand indicator for planning human and financial resources to attend to the health of the population.

goals

The objectives are divided into two types: individual and collective. The main objectives of epidemiological surveillance at the individual level are three.

The detection of health hazards, the identification of human groups susceptible to risks and the adaptation of the population to the plans.

At the collective level, the objectives are the diagnosis of the health situation and the timely detection of new risks, then the planning of priority and necessary preventive actions.

Components of the epidemiological surveillance system

Initial diagnostic

Before analyzing, processing and interpreting the information collected, a prior diagnosis of the situation must be carried out, either for the design of a specific program or for routine purposes and updating of the general plan.

Periodically, said initial diagnosis must be updated taking into account various variables such as socioeconomic aspects of the population, as well as geographical distribution, environmental and climatological resources, sources of contamination, etc.

Entry

This is a very important component of the epidemiological surveillance process. The accuracy of the diagnosis and the design of the strategy to deal with a situation largely depend on effective data entry or collection.

Prosecution

It has two components: the analysis of the information collected and its interpretation. Information processing should be done through a quick and clear management and work organization scheme. In this way, the accumulation of erroneous or useless information is avoided.

Likewise, it is necessary to define the flow and quantity of information that will be processed together with its periodicity, place of collection and emission, from the primary source to the highest instance of the system and vice versa.

Analysis and interpretation

The raw data collected is analyzed and interpreted in order to draw conclusions about the study or research program. The information is grouped by categories with their respective observations.

Departure

This phase of the epidemiological surveillance system involves the proposal made from the analysis and interpretation of the data. Likewise, the action plan to follow for the dissemination of information is executed.

Information bulletins are then designed for the management and execution levels of the system (doctors and nurses), as well as for the general population.

Feedback

It involves the evaluation of the results obtained and of the system in general to adjust its structure or plans.

Types

There are several types of Epidemiological Surveillance Systems (EVS), which are established according to their coverage, objectives, budget, human resources and interest for state and non-governmental organizations.

Universal EVS

It covers the total number of cases in the population studied, which is why it is called "population-based". It involves all institutions that collect information on risks or events.

EVS from case samples

It is based on a part of the collected cases; that is, it comprises a representative sample of all the events. It must be sufficiently representative of the total population analyzed to be able to make realistic inferences.

EVS of institutional records

It is based on cases taken from institutional records that are periodically reviewed in order to identify and analyze some variables of interest.

Here, proper identification of the institutions and their sources is very important: medical records, emergencies, patient admissions and discharges, police reports, etc.

The EVS of institutional records requires great precision regarding the periodicity of the information collected. It also requires determining the mechanisms used, the treatment of information, its evaluation, subsequent dissemination and the selection of variables.

Sentinel-type EVS

One or more institutions are chosen to determine the tendency of the problem to analyze and focus the planned EVS activities.

Preventive interventions are suggested. Here, representative samples of the population are not taken, but risk situations are determined as a priority in order to make decisions.

Examples of this are hospitals with higher morbidity and police stations with more crime cases.

EVS by surveys

The information is obtained through surveys or questionnaires oriented towards the collection of information on specific topics; it must be done during defined periods. This type of EVS is combined with population samples in order to determine possible epidemics.

An example of this type of system is the increase in suicides or crime with certain common characteristics.

Laboratory EVS

It is used to obtain specific information, confirm diagnoses or even to verify other possible risk factors. Its usefulness or importance increases when the purpose of the information obtained in this way serves to establish possible risks of collective interest.

Importance

Epidemiological surveillance is vital to detect serious public health problems. It serves to design short and long-term strategies to confront and combat infectious diseases. It is also important in case of situations or events that endanger the life of a certain population.

The monitoring carried out through the Epidemiological Surveillance Systems is generally carried out by governments at all levels (national, regional and local). These include individual cases and the evaluation of collective cases.

It seeks to identify the causes of epidemics or cases and the systematic, timely and reliable compilation of data on a population. The analysis and interpretation of these data will be the main input that the government will use to make decisions about situations.

Examples of this are gastrointestinal, dermatological events, viral hepatitis, sexually transmitted diseases, etc. EVS serve as the basis for drawing up public policies for the prevention and defense of the population's health.

References

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5. Epidemiological surveillance at work (PDF). Consulted of osalan.euskadi.eus.
6. Epidemiological surveillance. Retrieved from who.int.