Long before the COVID-19 pandemic, the public health sector has been advocating for and has been taking important steps toward more integrated public health surveillance systems. The World Health Organization (WHO) Integrated Disease Surveillance and Response (IDSR) strategy, implemented in the Africa region[i] since 1998, is an illustration of resolute steps towards ensuring that the scope of surveillance is no longer limited to a few diseases within the health sector but is broadened to span across a large array of relevant diseases and fields. For public health, surveillance is defined as “the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health.”[ii] Previous versions of the IDSR focused less on integrated health systems to identify and respond to public health emergencies and the promotion of a multisectoral One Health approach.
More than ever, the public health sector now understands the need to extend surveillance beyond the traditional scope of the IDSR provisions to include all sectors adopting a One Health approach and embracing the use of new information technologies. Even though there is an increasing trend to adopt the multisectoral One Health approach, we feel the urge to emphasize the importance of including different sectors and all levels of the health system to ensure that public health surveillance fulfills its expected function of identifying health emergencies rapidly and monitoring them over time to ensure appropriate responses. The human health sector, the area predominantly concerned with traditional surveillance, needs to collaborate more with the animal health, agriculture, and environmental health sectors to form a holistic approach to public health surveillance that is known as the One Health approach. Among other reasons justifying this collaboration are an increasing number of human infectious diseases caused by animal pathogens, also known as zoonoses, and the more blatant impacts environmental factors have on human health.
Surveillance as comprehensive health data collection
Across institutions, the definition of public health surveillance that integrates data collection, analysis, and dissemination has largely remained the same. Without evidence in the form of data it is difficult to make a case on any subject, whether criminal investigations or clinical medical practices, and this applies to public health practice as well. The importance of data gathering lies in the fact that it is the foundation for sound judgement on the status of public health and identifying the emergence of new public health issues in any given community. Complete and accurate public health data is the cornerstone to proper understanding of disease, achieving and tracking health program goals, and use of resources. Without data we are relying on unverifiable facts or rumors, historical trends, or hearsay, all of which will not offer the evidence needed for a comprehensive, accurate, and relevant response to emerging issues.
The types of data collected and used in public health surveillance come in diverse forms. There are data that play a role in defining health problems in a community. Such information focuses on the type of pathogen involved, the mechanism of infection, symptoms, the infected population, and the morbidity and mortality rates. This type of information can be collected in clinical settings such as health facilities that range from primary to tertiary health system levels.. When the given information is gathered at the public health department level, an analysis can provide a high-level characterization of the disease. Indicators that can be used include incidence or proportion of individuals who newly develop a condition within a particular time period, and prevalence or proportion of people who have the condition during the period, disease severity, mortality rates, productivity loss, premature mortality, and cost in medical care. All this information is instrumental in making policy and funding decisions[iii].
Surveillance systems as a tree with different branches and levels
Community-based surveillance (CBS): Communities are at the center and the primary target of public health surveillance as it aims at identifying public health events and responding to them in concerned communities. Placing communities at the center of this activity is intuitive and affords a sound approach to conducting public health surveillance. However, it is not until recently that public health surveillance experts understood and implemented active involvement of communities in identifying, reporting, monitoring, and responding to health events concerning them.
CBS has several advantages since communities have the ability beyond any other structure to quickly detect and monitor changes in a community’s health status. The proximity of community structures to its members allows faster and more efficient mobilization of its members for action during public health events of concern. Being able to create a sense of ownership and collaboration within the community is one of the main assets of this form of surveillance that is embedded within the community structure as it helps to create a sense of urgency to tackle health crises affecting local populations[iv]. It also puts the community at the center of owning, designing, leading and managing the response which is consistent with the global focus on localization.
Surveillance in healthcare facilities: Facility level surveillance is based on routine data collected for the purpose of medical treatment and follow-up of patients cared for by healthcare facilities. This type of surveillance is passive, where facilities transmit the data collected periodically to health departments as mandated by public health law in most WHO member states.
Surveillance at facility levels puts the healthcare provider at the center and heavily relies on health professionals not only to collect and transmit data but to also use their best judgement to inform health departments when there are unusual occurrences of diseases among patients being cared for. Disease can be unusual as seen through the types of patient symptoms observed, but also in the number of patients showing specific symptoms or group of symptoms which together constitute a syndrome.
Community and facility levels of surveillance are complementary and both play a significant role in Early Warning Alert and Response Systems (EWARS), a very important mechanism that is involved in quick identification, reporting, and response to outbreaks in communities. When these two levels of surveillance are well organized and succeed in obtaining the buy-in of concerned stakeholders, outbreaks can be detected faster, and response mechanisms mounted in due course.
District, regional and national level surveillance
Depending on the structure of a particular health system, information collected from the community is first transmitted, verified, and confirmed at the health facility in charge of that community before it is escalated to the health district or department level which collates the information for regional and national levels. Most importantly, the health district or department is the first systemic level of decision-making where response activities are organized and initiated before more support is sent or requested from the upper layers of the health system.
Typically, the regional level administers and deliberates over several health districts, analyzes data, and monitors trends in priority diseases in their jurisdiction. The region also ensures that data is transmitted to the national level and coordinates with national stakeholders any need for support to the districts that need to respond to health crises concerning the communities they oversee.
Coordination and communication across all levels of the health system is central to success and informs efforts for the collection of comprehensive and accurate data for early detection and response to health emergencies. When we fail to establish clear and effective communication mechanisms between the different levels of the health system, we run the risk of not capturing quality data to inform quick public health decisions in response to health emergencies.
An ever-evolving concept
For decades, scientists and health experts have for the most part waited for public health threats to emerge before responding to them. Again, passive surveillance has been the traditional method of tracking disease trends using routine data reported from healthcare facilities and practitioners. Using routinely collected data to identify public health threats is important. However, it has several weaknesses, primarily inconsistencies in data and delays in informing outbreak control measures — delays that can end up costing millions of lives and significant economic and societal costs.
Today, we can uncover potential threats before they surface. While passive surveillance is routine and ongoing, another method of detecting emerging, threatening diseases is active surveillance. It allows for scientists to proactively collect relevant information at the source instead of waiting to react to second-hand information. Active surveillance, which first emerged in the early 1990s, provides more accurate and timely information, allowing for more effective and rapid responses. Today, active surveillance has ever-greater capabilities to protect us from future outbreaks as emerging infectious diseases are discovered in real time, allowing the quick development of control measures and their deployment with limited delays.
Surveillance data collection, storage, and reporting has also long evolved from a paper-based system to a heavily computerized system that uses recent technological developments to boost the speed and ease of using health information. The most recent challenges being tackled in this new age of information systems is the integration of health-related data from diverse sectors, including animal and human health, as well as the environmental sector to ensure that climate change data are accounted for in communities’ health status. The integration of human, animal, and climate factors in characterizing health status is again known as the One Health approach, which recognizes the role of interactions between humans, animals, and the environment in the transmission of pathogens between species and the impact that the environment also plays in determining human, animal, and environmental health. Additionally, other new technologies, including mobile health (m-Health) and artificial intelligence are playing an increasingly important role in revolutionizing health surveillance.
Historically, pathogens such as influenza, monkeypox, smallpox, and polio among others that were previously under control are now resurging due to genetic mutations, raising the need to also track for variations in the genetic make-up of germs. Genomic surveillance has hence been birthed in the past few years, allowing the scientific community to track changes in known pathogens that permit them to take new and different courses in their capacity to infect and cause more severe infections and make them more difficult to treat. Cognizant of these trends in disease surveillance tools and methods, FHI 360 is tracking and building further capacity to play its part in providing technical assistance to countries, especially in low- and middle-income countries (LMIC) in order to be continually relevant through these state-of-the-art methods.
A public health activity with a single and unique goal
Surveillance, as described in the above sections constitutes the detective branch of public health practice. When done properly, surveillance provides a tremendous wealth of information to the public health community at all health system levels and to the global scientific community to make appropriate decisions for the sake of preserving and protecting the health of the community. Early Warning, Alert and Response Systems are built on the premises that the data is appropriate, collected in a complete manner, and transmitted in a timely fashion for compilation, dissemination, and decision-making purposes.
Early detection of unusual diseases trends is paramount to ensuring quick control of emerging infectious diseases whenever they arise. Unusual infectious diseases include those crossing from animals to humans, otherwise referred to as zoonoses, previously unknown infectious diseases, and rare and formerly eradicated diseases. The occurrence of these types of infections are illustrated by the COVID-19 pandemic, equine encephalitis in its many forms (Eastern, Western, Venezuelan equine encephalitis), and avian influenza outbreaks among others. Zoonoses are expected to rise in frequency given recent changes observed in interactions between animals including wildlife, and humans, sometimes impacted by climate change. All these dynamics impose a concerted approach to preserving health across all concerned sectors.
In the end, all sectors should strive to join efforts and go beyond sectoral considerations and siloed work for the sake of working toward an integrated surveillance system in which they all contribute, learn, and gain from their mutual collaboration. Such a common approach not only will pull resources together to ease interrelated work but will above all aim to protect the health of every community around the world.
[i] WHO, 2021, Technical Guidelines for Integrated Disease Surveillance and Response in the African Region: Third editio
[ii] German et al., 2001. Surveillance, Measurement, and Data Collection
[iii] Unite for Sight, 2022. Importance of Surveillance and Detection in Public Health Initiatives. Module 1: Importance of Surveillance and Detection in Public Health Initiatives (uniteforsight.org)
[iv] WHO AFRO, 2014, Integrated disease surveillance and response in the African region A guide for establishing community-based surveillance, DISEASE SURVEILLANCE AND RESPONSE PROGRAMME ARE A DISEASE PREVENTION AND CONTROL CLUSTER (who.int)
