What is Public Health Surveillance and its types?
Throughout many generations governments of the world tried their best to preserve their people by observing or surveying the public on potential outbreaks or current illnesses. To understand the epicenter of the sickness, there were many strategies involved which to these days evolved into a full-blown surveillance system. To understand what health surveillance is, we first need to understand what are the implications and how this definition came about. According to CDC: Public health surveillance is the continuous collection of systematic analysis and interpretation of health-related data for planning, strategizing, and evaluating public health at large.[1]
Public health plays an essential role in public good and well-being, as it is a very wide and integrative field that touches so many lives daily. For public health professionals to understand the full scope of disease and the amount of medical or physical labor needed, they need to understand the roots of the main pathology. It’s simply impossible to predict or even implement a successful treatment or prevention plan without first implementing a health surveillance practice. The main objective of the surveillance system is to understand the main cause or even source of the disease, what types of patients are affected (ethnical, sex, and geographical makeup), and more. The surveillance system could be described as a spy system to eradicate or prevent the disease from affecting on a macro level, so it’s safe to say that any surveillance system starts at the micro level to pinpoint the cause and then expands to the macro capacity.
There are different types of surveillance systems in place, and in general, they have the following objectives:
a. Develop main clinical objectives needed.
b. Develop a case definition.
c. Determine data collection sources and instruments needed for proper execution.
d. Field or remote test methods. This potentially involves IT decision-makers to help with the process.
e. Implement an analytical database and data entry source for the team to contribute.
f. Develop dissemination methods.
g. Analysis and interpretation of the final results and release to the public officials.
In general, the surveillance could be divided further into active or passive surveillance, categorical, integrated and syndromic surveillance[3]. Depending on the objective (see above), the actual surveillance could be divided further. But for the purpose of this paper let’s briefly review these ones.
Active surveillance refers to the health professionals actively delivering results of interested disease or lab results to the public health or epidemiology centers.
Passive surveillance is contrary to active surveillance and may involve a healthcare institution periodically delivering results on the subject matter. This type of surveillance, it’s given based on the convenience of a healthcare facility and is not actively pursued by a dedicated staff.
Categorical surveillance refers to the surveillance of one or more diseases and is mostly micro-focused on specific criteria. The limit of categorical surveillance in public health settings is that it doesn’t provide sufficient data to implement on a national level.
Integrated surveillance could be referred to as a hybrid system of surveying interest groups. It could be active and passive and involves different levels of team members. During the integrated surveillance several co-related diseases could be tracked; one of the popular ways to integrate integrated surveillance is to monitor hospital-acquired infections in the telemetry unit. In the telemetry unit there is a wide range of patients from cardiac care to post-stroke patients, so monitoring these patients to identify a hospital-acquired infection could be a part of integrative surveillance.
Syndromic surveillance refers to the full clinical observation of signs and symptoms without employing any laboratory data. Syndromic surveillance is one of the fastest and cheapest ways to assess the interest group. This type of surveillance is usually non-specific but rather very broad, as laboratory data is not available in this type of study, it will be hard to differentiate the exact diagnosis of the given disease. For example, a syndromic surveillance evaluation of general cough could be registered, but what is the underlying cause would be hard to define. This type of surveillance is usually implemented in the low-and-middle-income countries where budgetary and specialized labor constraints are present. This type of study can provide officials with an overview of how much further studies are needed, in order to further pinpoint the source of disease and its eradication.
In summary, public health surveillance is a necessary tool that can provide data that is vital for sustaining a healthy nation and eradicating burdensome diseases. In times of COVID-19 pandemic, active categorical surveillance has been adopted worldwide, in order to differentiate COVID-19 symptoms from regular flu. However, some scientists still argue that there is no clear-cut line between COVID-19 symptoms and flu.[4]
References:
1. Centers for Disease Control and Prevention. (2018, November 15). Introduction to public health surveillance|public health 101 series|cdc. Centers for Disease Control and Prevention. Retrieved November 25, 2021, from https://www.cdc.gov/training/publichealth101/surveillance.html.
2. Teutsch, S. M., & Thacker, S. B. (1995, March). Www3.paho.org. Pan American Health Organization. Retrieved November 25, 2021, from https://www3.paho.org/english/sha/epibul_95-98/be951survll.htm.
3. Nsubuga P, White ME, Thacker SB, et al. Public Health Surveillance: A Tool for Targeting and Monitoring Interventions. In: Jamison DT, Breman JG, Measham AR, et al., editors. Disease Control Priorities in Developing Countries. 2nd edition. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2006. Chapter 53. Available from: https://www.ncbi.nlm.nih.gov/books/NBK11770/ Co-published by Oxford University Press, New York.
4. Czubak J, Stolarczyk K, Orzeł A, Frączek M, Zatoński T. Comparison of the clinical differences between COVID-19, SARS, influenza, and the common cold: A systematic literature review. Adv Clin Exp Med. 2021 Jan;30(1):109-114. doi: 10.17219/acem/129573. PMID: 33529514.