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2009 H1N1 Pandemic Provided Lens For Examining Surveillance Systems

Lessons Should Guide Future Surveillance Efforts

JUNE 2, 2011—Baltimore, MD—The 2009 influenza A/H1N1 pandemic was the first test of the local, national, and global pandemic response plans that have been developed over the past few years. During this pandemic, public health surveillance provided a critical evidence base for many decisions, but the practical challenges of gathering data during an emerging pandemic became clear. It was also evident that such decisions, with their significant public health and economic consequences, must often be made before many key data are available, including information regarding transmissibility and severity of infection.

In an article in the June 2011 issue of Biosecurity and Bioterrorism, a distinguished group of authors look at the needs for surveillance in terms of the key decisions that must be made in response to a pandemic: how large a response to mount and which control measures to implement, for whom, and when. The article describes the sources of surveillance and other population-based data and concludes with key lessons of the 2009 pandemic for designing and planning surveillance in the future.

This article synthesizes discussions from an international meeting, “Surveillance for Decision Making: The Example of 2009 Pandemic Influenza A/H1N1,” which was held at the Center for Communicable Disease Dynamics at the Harvard School of Public Health in June 2010. The participants included many of the foremost experts in the field of influenza research from academia and state and local public health agencies on three continents, as well as from WHO, CDC, and HHS.

Senior author Dr. Marc Lipsitch notes: “The 2009 pandemic was in most respects the best-documented, most data-rich influenza pandemic ever. It’s important to understand and capture the many things that were done well, so that the successes can be repeated in future events (influenza and otherwise). It’s also important to identify what critical data were either unavailable, slow to become available, or not widely disseminated, so that we can improve our systems for the future.”

The authors reflect on the nature and timing of decisions made during the course of the first year of the pandemic and on the corresponding urgent need to gather surveillance data and process it into useful evidence. Their goal is to suggest how surveillance systems can be improved to provide better, more timely data to estimate key parameters of a future pandemic, with the goal of improving how it is managed.

“Surveillance can be resource-intensive, so it is critical to identify how specific types of data can be used to inform specific clinical guidelines, forecasts, or policy decisions. This article places all of the surveillance and analysis that was done in 2009 in that context—what decisions had to be made, and what information was needed to make them effectively. The article draws lessons from the 2009 pandemic about what data we had, what we didn’t have but needed, and how various analytical approaches to the data provide the evidence needed to make better decisions. Looking forward, there is an agenda for developing surveillance capacity further and for improving integration of different data forms so that analysts and decision makers will have access to a common set of information,” says Lipsitch.

The article and the meeting on which it was based were sponsored by the Models of Infectious Disease Agent Study (MIDAS) at the National Institute of General Medical Sciences, National Institutes of Health.

The article, titled “Improving the Evidence Base for Decision Making During a Pandemic: The Example of 2009 Influenza A/H1N1,” by Marc Lipsitch, Lyn Finelli, Richard T. Heffernan, Gabriel M. Leung, and Stephen C. Redd; for the 2009 H1N1 Surveillance Group, appears online ahead of print in the June 2011 issue of Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science, a peer-reviewed journal published by Mary Ann Liebert, Inc. ( The article is available free online at


Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science, published quarterly in print and online, covers topics such as bioscience, medical and public health preparedness and response, infrastructure and institutions, international collaborations, agroterror/food safety, infectious disease surveillance, and citizen response and responsibility in all matters related to national and international biosecurity. It provides an international forum for debate and exploration of the many key strategic, scientific, and operational issues posed by biological weapons, bioterrorism, and other major health-related events.

The Center for Biosecurity is an independent, nonprofit organization of the University of Pittsburgh Medical Center (UPMC) whose mission is to strengthen national security by reducing the risks posed by biological attacks, epidemics, and other destabilizing events, and to improve the nation’s resilience in the face of such events.



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