While the concept of using data to track epidemics dates at least as far back as ancient Egypt, using mortality and morbidity data to explicitly guide public health actions took longer to achieve. Some estimates date its emergence to the fourteenth century with the invention of quarantine to prevent the spread of the Black Death. Despite this long history, the challenge facing many countries (regardless of income level) has been one of balancing investments in the infrastructure and human resources needed to perform surveillance, while providing essential services to respond to current health needs and investing in actions to prevent new ones.
Brazil has a rich history of epidemiologic and public health surveillance and has experienced a significant acceleration of efforts since the turn of the century. Essential investments have been made in improving the completeness and accuracy of vital statistics, along with launching new methods and approaches to monitor non-communicable diseases, injuries, and behavioral risk factors. The articles in this issue demonstrate the breadth and scope of these efforts, illustrate how such data can be brought to examine a range of important issues, and suggest growing sophistication in methods and approaches, especially within the past decade.
Chief among recent accomplishments include the systematic and regular use of behavioral risk factor surveys, such as Vigitel, to capture changes in prevalence rates of behaviors and health risks, universal notification of significant events (such as interpersonal violence), use of administrative data (emergency room and hospital data for tracking injuries), as well as data linkage and capture-recapture techniques to allow for examination of cases across information systems. The articles clearly show how such surveillance efforts are part of national strategies to identify and address health and other social inequalities.
While impressive, experiences in the United States and elsewhere suggest that these achievements will remain successful only as long as they are actively supported. Far too often successful public health efforts worldwide have been jeopardized - somewhat paradoxically as a reaction to a sense that they have already served their purpose - due to shifting political and financial priorities. Indeed, against the backdrop of Brazil's rapidly aging population, increases in chronic disease risk factors such as obesity, and rising rates of transport-related and other types of injury, it is likely that increased resources will be required as population needs become ever more complex.
To that end, key challenges for public health surveillance in Brazil are likely to include the need to continue to combine surveillance and other routine data to the ongoing monitoring, evaluation, and continual improvement of public health policies and programs. This linkage demonstrates the essential nature of surveillance in the efficient and effective functioning of a national public health system like the SUS. The development of new information systems (such as electronic health records) will require building in comparability and interoperability to enhance their potential for improving health. It is also likely that new approaches will be needed to collect surveillance data in real time through social media, crowd-sourcing, and analysis of "big data". Such approaches have been particularly helpful in large events and in reaching vulnerable and other key populations that may not be easily identified through standard demographic variables. Meanwhile, new systems may be needed to handle emerging challenges, such as tracking prescription drug use (and misuse) while existing systems may need to expand to incorporate surveillance of other conditions, such as mental health. Finally, there will likely be a need to enhance the link between strengthened surveillance approaches and information dissemination to public health authorities and the public at large. These efforts will be essential to maintain investments in the surveillance systems themselves as well as the human resources and technologies needed to design, collect, analyze, and act on public health surveillance data in an effective and timely manner.
As challenges such as global climate change and its associated effects threaten new health hazards, investments made in strong and responsive surveillance and public health actions will have a considerable role to play in Brazil's continued trajectory towards a more equitable, prosperous and sustainable future.
- Publication in this collection