Passive surveillance is the collection of data from those who voluntarily report it, such as hospitals, healthcare providers, parents, or health departments. Surveillance is the process or system for tracking cases of risk factors, medical conditions, cases of diseases, adverse events, etc. It is often used to track the incidence of a disease or the side effects of drugs or vaccines. The two basic types of surveillance are active and passive. Active surveillance involves actively searching for cases through a notification system or through a systematic protocol, such as calling all health departments in a region during a disease outbreak.
Another form of active surveillance is the use of a Remote Surveillance Trailer in Santa Ana CA to monitor and track potential cases in a specific area. Deeper dive With passive surveillance, no one actively and systematically searches for specific cases. Passive surveillance is useful for detecting patterns or “signs”, such as a cluster of cases of illness or a higher-than-expected notification of side effects from a drug. The biggest limitation of passive surveillance is not knowing the denominator, that is, the total number of encounters or people whose cases are reported, since the notification is voluntary and self-selective. Active surveillance, on the other hand, has a clear denominator, the total number of people, clinics, hospitals, populations, etc.
With active surveillance, the incidence or prevalence (the numerator) can be established as a fraction of the evaluated population (the denominator). Vaccine Safety Datalink (VSD) is an active surveillance program that researchers can use to search for a specific adverse effect among a set number of patients who received a vaccine (the denominator). Human health surveillance systems continuously monitor changes in natural patterns and the presence of diseases, the increase in the number or severity of cases of a specific disease, unusually severe cases of a disease, the unusual geographical spread of a disease, and groups of non-seasonal diseases. Surveillance systems are based on the continuous collection, analysis and interpretation of health-related data19. PulseNet from the CDC uses molecular subtyping tools to generate DNA fingerprints of bacteria that make people sick.
This national network of laboratories connects cases of foodborne, waterborne and related diseases to One Health20 to detect thousands of local and multi-state outbreaks.21 Passive surveillance data also includes traditional reporting of cases of diseases that may pose a threat to public health and that local doctors and hospitals must report by law to public health authorities.22 It is important to emphasize that passive systems need design and care dynamic. The most commonly used passive systems are disease reporting systems, which require doctors to submit disease reports to a central institution. These diseases are generally notifiable through legislation. Laboratory systems produce surveillance data when samples are passively received for microbiological diagnosis or reference.
Death reports, illness records, hospital records, and physician billing systems included in health insurance plans are examples of passive surveillance. Many countries have passive mechanisms for reporting outbreaks of infection in order to intervene quickly. Obtaining exposure data, which may include estimates derived from hazard data using sophisticated models or direct measurements of individual exposure obtained through the use of personal monitors (for example, passive air samplers), is not usually practical in developing countries. Blood lead levels in children are the only biomonitoring data that is routinely collected in several countries, either in national surveys or in screening programs for high-risk children.
Foodborne illness surveillance provides the framework within which public health officials can act to control and prevent diseases that can be acquired through food. Surveillance is necessary to determine the occurrence or significant changes in the frequency or distribution of cases. These observations are an ongoing process for determining the extent of the disease and the risk of transmission and for evaluating the impact of prevention and control measures. Disease surveillance is the regular collection, monitoring, and analysis of data for the control and prevention of diseases or other conditions. The data can be used to determine baseline levels of the disease.
By knowing the reference point, unusual cases of illness, such as an increase in incidence or an abnormal distribution, can be identified. An active surveillance system is one in which public health officials regularly request reports on diseases. This is often done by regularly calling (daily, weekly, or biweekly) selected individuals, usually doctors, infection control professionals in hospitals, laboratories, schools, urgent care clinics, etc., and asking them if specific diseases have been detected. This type of system has been shown to double the number of complaints of some diseases.
Active surveillance is also used during outbreak investigations. In active surveillance, the organization receiving the information takes direct steps to collect it. This can also occur by reviewing medical and laboratory records, interviewing people who are involved in investigating an outbreak, or screening high-risk populations. A passive surveillance system, such as the Iowa system for routine reportable diseases, is one where individuals are notified (that is, doctors, infection control professionals in hospitals, laboratories, or individuals themselves if they file a complaint about a foodborne illness, etc.).It is the most common routine surveillance system used by state and local public health agencies. The two main limitations of this type of system are underreporting and late reporting.
A subcategory of passive surveillance is “enhanced passive surveillance,” in which the organization receiving the data works closely with healthcare providers and laboratories that are most likely to report a particular disease or group of diseases and establishes systems to increase the timeliness and completeness of reporting. One method for gathering information about a possible foodborne illness is to complete the preliminary foodborne illness complaint form when a complaint is received. See Chapter 6 Complaint Handling for additional information on the use of the preliminary food-borne illness complaint form. By submitting reports, a surveillance system receives a timely and regular flow of information about cases.
As mentioned, some reportable diseases in Iowa can be acquired through food. Most are gastrointestinal, such as salmonellosis, and, once confirmed, local public health agencies collect and report additional information using the enteric disease monitoring form. There are several case notification forms available for other notifiable diseases that can be transmitted by food, such as listeriosis and trichinosis. These forms are found in the Epidemic Manual for each specific disease.
When a health care provider, laboratory, or other information source notifies a local agency about a notifiable disease, they must report it to the IDPH as soon as possible. The local public health agency (LPHA) will begin to collect the requested information and record it on the enteric disease monitoring form or other appropriate case reporting form. Since initial case reports usually contain minimal information, completing the follow-up form can provide clues to determine a possible or probable means by which a person may have become infected (for example, to complete the follow-up form, it may be necessary to contact the laboratory or provider to obtain the information needed to contact the sick person (address, telephone numbers, etc. The Center for Epidemiology of Acute Diseases (CADE) collaborates with LPHAs in the research on communicable diseases and implementation of appropriate control and prevention measures.
The guidelines in this manual, as well as other reference material, form the basis for reporting, research, and control of communicable diseases by local public health agencies. In the case of foodborne illnesses, local health departments assume the primary role in investigating individual cases of notifiable diseases. When an institution, such as a health center or school, is the site of possible transmission, the facility's infection control personnel or school nurses should be involved in research and implementation of control and prevention measures. Ideally, the IDPH, the LPHA and the infection control personnel (or their equivalent) of the affected institution should jointly make decisions on control measures. However, the IDPH and the LPHA, if they work together, have the highest authority.
All cases of illnesses reported to IDPH are reported to CADE using an official case report form. Certain diseases must be reported immediately to CADE by telephone when a suspected or confirmed case is identified (see the disease notification poster). Diseases that require immediate notification should be prioritized over other case investigations. In addition, any suspected disease group or outbreak should be reported immediately and prioritized.
accordingly. After the investigation, the local public health agency can follow up with official case report forms. All diseases that are not classified as “immediate” must be reported and investigated within one week, and a complete case notification form must be submitted with appropriate laboratory confirmation (if appropriate to the disease). The importance of timely notification can never be overemphasized.
For example, if a local health authority reports cases of salmonella and only files them once a month, a possible outbreak that occurs from one county to another may go unnoticed and without control. The IDPH strongly recommends that local public health agencies purchase a secure fax machine for use by individuals involved in the notification, research, and control of communicable diseases. It must be located in a safe area where disease control personnel work and must not be accessible to the public. The fact that communicable disease control personnel and city or county government personnel share a fax machine poses a risk of a breach of confidentiality.
Case reports and records on the investigation of an outbreak should not be left out in sight and should ideally be kept in a drawer or closet when not are using. It is important to recognize the types of information that may allow the identification of a case or a company. This can change with each situation. For example, demographic information, such as age, race, gender, or zip code, may or may not be disclosed based on factors such as the extent of the outbreak and whether it can be traced back to an individual case.
The general rule is that if the information being disclosed can identify a person or company or can be traced back to an individual case, the information should not be disclosed. Local and state public health authorities have investigated cases of infectious diseases and have collected sensitive information for more than 100 years. These efforts would not be as successful if all staff failed to maintain the public's trust while maintaining strict confidentiality. Recently, concerns have been raised about the disclosure of medical records for public health purposes, in light of the recently enacted Health Insurance Portability and Accountability Act (HIPAA). The HIPAA Privacy Rule states that a covered entity may, without individual authorization, disclose private information to a public health authority for the purpose of preventing and controlling diseases, injuries, or disabilities, including, but not limited to, reporting illnesses, injuries, or vital events and carrying out surveillance activities, investigations, and public health interventions. Health care providers don't always inform patients that an illness is notifiable to local or state health departments.
This can cause distress in patients when they are contacted for research. Educating healthcare providers on this topic is a good strategy for local public health agencies, who must determine when the test results and diagnosis were communicated to the patient. It is usually best to start an investigation by contacting the reporting doctor. Laboratory reports are often sent directly to the IDPH.
This has allowed for more timely notification of diseases. The IDPH sends the results to local health agencies for follow-up. Some laboratories group test results and submit them periodically, which can cause long delays in receiving and identifying or confirming cases. The IDPH is working to eliminate this practice through laboratory education and the implementation of electronic transmission of laboratory data. As part of the investigation form for cases of diseases caused by possible foodborne pathogens (such as salmonellosis), the appropriate person fills out a case investigation report form, which is submitted to CADE.
Case responses to exposure history may reveal that food was a possible or probable source of the infection. The case investigation report forms are entered into a large computer database. Diseases are routinely analyzed for trends. Occasionally, more cases of a given disease are reported than would be expected or have a single distribution. In these situations, CADE attempts to determine the similarities between the cases and to determine if an outbreak is taking place.
It is clear that the monitoring of reportable diseases at the local level is essential to identify generalized groups of foodborne or other diseases. Perhaps the most important reason for using the preliminary foodborne illness complaint form is that it allows local and state public health officials to “speak the same language about foodborne illnesses.” Standardized data shared between agencies will be more easily interpreted, providing an opportunity to respond more quickly. By routinely examining the data, answers will emerge to these and other questions about foodborne illnesses in the community. These answers will help guide policymaking, allocate resources to the most common problems, and identify potential outbreaks of diseases transmitted by food.
Health conditions are not reported randomly. For example, illnesses in a health facility are reported more often than those diagnosed in outpatient care. A provider is more likely to report a case of hepatitis A if the patient is sick than if the patient has few or no symptoms. Reporting bias can distort the interpretation of data about the disease.
Professionals use a variety of case definitions for health problems. The more complex the pathological syndrome, the greater the difficulty in reaching a consensus on the definition of a case. With newly emerging diseases and as understanding progresses, case definitions are frequently adjusted to allow for greater accuracy in diagnosis. In addition, as new diagnostic tests are developed, case definitions sometimes change to incorporate them. Case definitions establish uniform criteria for disease reporting and are not definitive for diagnosis.
The use of outdated or different case definitions may lead to incomplete or insufficient reporting of the disease. Communities will lead the response to a bioterrorist event or to any emergency related to an infectious disease. Planning and communication are extremely important and will be more effective if there is a strong partnership between public health, first responders, for example. State agencies, such as the IDPH and the Department of Homeland Security, are available for consultation or assistance.
The best surveillance comes when accurate and timely data is collected and carefully and correctly interpreted. The interpretation should focus on the elements that could lead to the control and prevention of the condition. Researchers can use surveillance as a basis for taking appropriate public health measures. Community baselines can be established, epidemics recognized, preventive strategies applied and the effects of such actions evaluated. Lucas Building 321 East 12th Street Des Moines, IA 50319. Passive surveillance systems can be used to establish adverse event reporting patterns and monitor changes in those patterns as vaccines change (different batches, different formulations, different antigens) or as the populations receiving certain vaccines change.
While case reports can provide important information about causation in specific circumstances, participants generally agreed that passive surveillance systems serve better at detecting signs or warnings that there might be a problem rather than answering questions about causation. These signals can lead to hypotheses about causality, which can then be tested by other methods, such as epidemiological studies or laboratory surveillance. Passive surveillance is the use of local health services to collect data on the incidence of diseases or the adverse effects of medications. It is based on staff and services, which are part of a reporting network, collect data and generate reports.
There is no active case search. As most surveillance systems rely on passive notification of diseases by healthcare providers, it is inevitable that they are not properly reported. The results of these tests, in addition to their use for patient care, can also be reported to a passive surveillance program that analyzes the incidence of certain bacterial infections. It should be determined, for example, if the VAERS has really worked well as the signal detector that should be a passive surveillance system.
Some existing research on statistical modelling of adverse event reporting systems shows that relative risks must be very high (given the state of underreporting) or that the adverse event is extraordinarily unusual for passive reporting systems to detect adverse events. If the primary objective of passive surveillance systems is a signal detection system (especially for the detection of previously unrecognized adverse events, but also for the detection of a larger number of reports of a recognized adverse event), participants suggested that search strategies should focus on false positives and not false negatives. The disadvantage of this passive surveillance method is that the quality, completeness, and timeliness of the data collected are difficult to control. The collection strategies and the results of surveillance systems vary by state and can provide data immediately, for example, during ongoing investigations, or it may take weeks before passive reporting of data on some diseases is available. For example, passive surveillance is the most commonly used method to control the incidence of diseases that can be prevented by vaccination, so that national and international agencies can identify possible outbreaks and organize the supply of vaccines.
To better protect the population, whenever possible, a combination of active and passive detection systems, the analysis of effects on human health, the monitoring of signals on the environment and local animal populations and the observation of other characteristics of an incident should be used at the community level. However, as with questions of causation, without full information in each report, a passive surveillance system cannot answer these questions. Some deficiencies of passive surveillance systems are common to those of other strategies for evaluating adverse effects; for example, no data collection system, including LLDBs, can easily assess causality when several vaccines are administered simultaneously. Those who had reservations were concerned that the increase in complaints would only increase the noise inherent in the systems and that it would be better to invest the necessary resources to sufficiently improve passive surveillance systems in other investigative tools.
In a passive surveillance system, reporting is not deliberately encouraged by reminding health facilities to report diseases. Passive surveillance systems refer to systems that collect and analyze individual case reports of adverse reactions that doctors and patients submit to the system on a voluntary basis. The PHS Vaccine Adverse Reaction Reporting System (VAERS) is a fairly new passive surveillance system.
