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Before the Committee on Energy and Commerce, Subcommittee on Oversight and Investigations
United States House of Representatives

Bioterrorism Preparedness: CDC's Public Health Surveillance Activities

Statement of
Claire Broome, M.D.
Senior Advisor to the Director
Centers for Disease Control and Prevention
Department of Health and Human Services

For Release on Delivery
Expected at 9:00 am
on Thursday, November 1, 2001

Good morning, Mr. Chairman and Members of the Subcommittee. I am Dr. Claire Broome, Senior Advisor to the Director for Integrated Health Information Systems at the Centers for Disease Control and Prevention (CDC). Thank you for the invitation to update you on CDC's public health surveillance activities. I will describe the function of our current surveillance systems, update you on recent efforts to build surveillance capacity in state and local health departments, and discuss the status of the National Electronic Disease Surveillance System.

As the nation's disease prevention and control agency, CDC has the responsibility on behalf of the Department of Health and Human Services (HHS) to provide national leadership in the public health and medical communities to detect, diagnose, respond to, and prevent illnesses, including those that occur as a result of a deliberate release of biological agents. This task is an integral part of CDC's overall mission to monitor and protect the health of the U.S. population.

Much has been in the news lately about the disease detective function of CDC and its epidemiologists, including Epidemic Intelligence Service Officers. What has not been often emphasized is the need for continued watchfulness to first detect problems that our disease detectives then investigate. We refer to this function-- this constant state of alert-- as public health surveillance.

Public health surveillance is a crucial monitoring function for CDC and its partners. It is these ongoing data collection activities that help us detect threats to the health of the public. Without our public health surveillance systems, we might not identify outbreaks or other important problems in time to prevent the further spread of disease. We cannot investigate problems, identify their causes, and implement control measures if we have not detected them. Recent events have underscored this essential role of public health surveillance, as well as the integral role of health care providers in the overall public health system. For most of our surveillance data, the original source of information is the health care provider; the Florida physician's ability to recognize a suspected case of anthrax and his awareness of his role in reporting it to the local health department was critical to our initial recognition of the current bioterrorist events. Indeed, identification of subsequent anthrax cases has also relied on heightened awareness among health care professionals that the wounds and respiratory syndromes they were seeing were actually cutaneous and inhalation anthrax, not merely spider bites and pneumonia.

Current Surveillance Systems

The best initial defense against any threats to the health of the public, whether naturally occurring or deliberately caused, continues to be accurate, timely recognition of a problem. Key elements of our current surveillance systems include awareness and diagnosis of a condition of public health importance, whether by a clinician or laboratory, with subsequent notification of the local health department, which in turn reports to the state health department, which shares information with CDC. We work with our public health partners to define conditions that should be reported to public health departments; health departments share these definitions and guidelines with health care providers, infection control practitioners, emergency department physicians, laboratorians, and other members of the health care system. A timely example of such guidelines was included in the October 19, 2001, issue of the Morbidity and Mortality Weekly Report (MMWR), in the report that dealt with "Recognition of Illness Associated with the Intentional Release of a Biologic Agent." Copies of the MMWR have been provided to the Subcommittee.

The traditional operation of our surveillance systems generally consists of paper or facsimile reporting by providers to health departments. If a case of illness is particularly unusual or severe (such as a case of anthrax or rabies), the provider will call the local health department immediately. As mentioned, health care provider recognition of the illness and awareness that certain health events require immediate notification of public health authorities, is critical to our ability to detect problems and mount a public health response. It was another alert clinician in 1993, a pediatric gastroenterologist, who provided the early warning about a potential diarrheal disease outbreak to the Washington State Department of Health. Within one week, the Health Department identified hamburgers from Jack-in-the-Box as the cause of the outbreak, and the fast-food chain voluntarily recalled all hamburger meat from their restaurants in the state. However, for routine public health surveillance, this largely paper-based system is burdensome both to providers and health departments, and therefore reports are often incomplete and not timely. In addition, the volume of paper reports and the need to enter the information collected into various information systems leads to errors and duplication of efforts.

These shortfalls influence more than our ability to detect an event; surveillance also plays a pivotal role in event management. Surveillance data help us to determine where cases are occurring and who is affected (e.g., particular age groups or occupations such as children or postal workers), when cases are occurring (i.e., are cases still occurring; are the numbers increasing or decreasing with time?), and matching such information to the laboratory data about the particular agent, to trace its origin as well as to identify whether cases in different geographic locations might have resulted from the same source. Such information is vital to directing our investigation and control efforts, but it requires a well-designed system to input and analyze the voluminous data required, such as the thousands of swabs tested for anthrax.

Given the crucial function of public health surveillance, we have recognized the need to take advantage of recent information technology advances to bring our surveillance systems into the 21st century. First I will describe the overall direction that we are headed to transform our public health surveillance systems, and then I will describe some of our short-term efforts to enhance current surveillance systems in the aftermath of September 11, as described in the MMWR report mentioned previously.

Integrated, Electronic Surveillance Information Systems

CDC and its partners have recognized the need to build more timely, comprehensive surveillance information systems that are less burdensome to data providers. Several years ago, we initiated the development of the National Electronic Disease Surveillance System (NEDSS). The ultimate goal of NEDSS is the electronic, real-time reporting of information for public health action. NEDSS will include direct electronic linkages with the health care system; for example, medical information about important diagnostic tests can be shared electronically with public health as soon as a clinical laboratory receives a specimen, or makes a diagnosis. In the future, NEDSS coupled with a computer-based vital statistics system and computerized medical records, not only in hospitals but also in ambulatory care offices, could facilitate immediate awareness of unusual illnesses such as anthrax or smallpox, as well as our ability to detect more subtle problems that may be dispersed across the country.

NEDSS emphasizes a standards-based approach, relying on the use of standards for data, information architecture, security, and information technology (de facto industry standards). This reliance on standards will ensure that data need only be entered once, at the point of care for a patient, without a need for re-entry of data by our local and state partners. Use of standards is critical to ensure that our public health partners can use technology more effectively and collaboratively. As we build NEDSS we are ensuring that the data standards we use are compatible with those used in health care systems, so that we can make sense of health-related data and therefore detect potentially related cases across the country. In addition, a standard information architecture and appropriate, high level security will enable public health partners to share data in a secure fashion, which is critical for identifying problems that cross jurisdictional boundaries. And finally, the reliance on de facto industry standards for information technology ensures the availability of multiple commercial products to meet the needs of our public health partners, including state-of-the-art analytic tools and geographic information system capacity.

CDC has worked with our state and local partners on the development of NEDSS. We have provided funding and support to all 50 states for activities related to NEDSS planning and development. NEDSS is an ambitious project; defining appropriate standards and ensuring appropriate data sharing among the myriad health care systems, over 2000 local health departments, 50 state health departments, and numerous federal public health agencies is a complex process. As a start, a NEDSS Base System that incorporates the standards and functions mentioned will be deployed in at least 20 states during 2002. This project will ensure our ability to capture data efficiently, electronically, and to use it effectively for public health response. And a public health surveillance system that spans the nation will help detect threats to the public, wherever they might occur.

Indeed, 2 related projects also provide a key part of the effort to ensure the development of the public health communications infrastructure. Health Alert Network (HAN) is a nationwide program, the goals of which include provision of Internet connectivity and rapid communications capability among local and state health departments, which will also facilitate linkage of local health departments and health care providers. This connectivity will be crucial for rapid sharing of surveillance data among public health agencies. In addition, the Epidemic Information Exchange, or Epi-X, provides secure, high-speed, Web-based communication about outbreaks and other acute or emerging health events among public health officials from CDC, state and local health departments and the military. One of the unique features of Epi-X is the ability to provide a forum for secure communications for state epidemiologists to post information on surveillance and response activities for approximately 500 public health officials around the country, including the U.S. military. Another unique feature of Epi-X is emergency notification by telephone and/or pager to defined groups of public health officials.

Support to date for these important national projects has strengthened our public health infrastructure for detection of events of concern and subsequent communication to ensure appropriate public health response.

Near Term Surveillance Efforts

Recognizing the need for near term increased capacity while NEDSS is implemented, CDC and its public health partners initiated various activities to improve their ability to detect events of importance to the health of the public. For example, with the first CDC funding for countering bioterrorist activities, in Fiscal Year 1999, many state health departments were able to purchase the most advanced pattern recognition analytic capacity available today - - a trained human being: an epidemiologist whose duties included coordinating bioterrorism surveillance and rapid response activities. The activities range from enhancing communications (between state and local health departments and between public health agencies and health-care providers) to conducting special surveillance projects. These special projects have included active surveillance for changes in the number of emergency medical system/911 calls, hospital admissions, emergency department visits, and occurrence of specific syndromes. After September 11, these systems were explicitly called on to provide heightened surveillance information. CDC is undertaking a critical review of these activities to identify the most useful and practical approaches that may be implemented on a national basis. One key question to address is the feasibility of capturing medically relevant data in a timely and appropriately representative fashion, since we do not know when or where the next event might occur. Furthermore, what effort do proposed systems require from health care providers to report, or enter data in the systems? Can the systems be used in geographic areas beyond those where they were developed? In addition, given the substantial burden of investigating potentially concerning events, we are evaluating mechanisms for minimizing the proportion of alerts generated by the system that are false alarms.

Other related activities useful for early detection of emerging infections or other critical biological agents include CDC's Emerging Infections Programs (EIP). CDC funds EIP cooperative agreements with state and local health departments to conduct population-based surveillance and research that goes beyond the routine functions of health departments, and often involve partnerships among public health agencies and academic medical centers. In addition, CDC has established other networks of clinicians-- whether infectious disease or travel medicine specialists, or emergency department physicians-- whose functions are to serve as "early warning systems" for public health by providing information about unusual cases encountered in the clinical practices of its members. The guidance provided in the October 19 MMWR is intended to heighten awareness among these clinical partners about what to watch for, and what to report to public health. It is important to note that these relationships, particularly between health care providers and local health departments, are the foundation on which our surveillance systems operate. The local health department is the front-line of defense for the public health system. Many other projects and proposals for rapid surveillance omit the vital connection to public health, especially the local public health agency, which is responsible for the initial public health response.


In conclusion, CDC is committed to working with other federal agencies and partners as well as state and local public health departments to ensure the health and medical care of our citizens. The best public health strategy to protect the health of civilians against illness, regardless of cause, is the development, organization, and enhancement of public health prevention systems and tools.

Our public health surveillance systems provide a critical piece of the public health infrastructure for recognizing and controlling deliberate bioterrorist threats as well as naturally occurring new or re-emerging infectious diseases. We have made substantial progress to date in enhancing the nation's capability to detect and respond to problems that threaten the public's health. Recognizing that there is no simple solution for our surveillance needs, we have supported augmenting the staff in state and local health departments, as well as special projects to explore the usefulness of various clinical data sources. We are undertaking a critical review of current efforts to determine what would be feasible and useful to implement more broadly in coming weeks. We are implementing the National Electronic Disease Surveillance System, which will provide direct linkages with the health care system in 2002, improving the timeliness, efficiency, and usefulness of our surveillance efforts. These cross-cutting efforts to build the surveillance infrastructure will be useful to detect any problem, not just potential bioterrorist events; the ongoing use of this surveillance infrastructure will assure that it is familiar and functional should bioterrorist events continue to occur. A strong and flexible public health infrastructure is the best defense against any disease outbreak.

Thank you very much for your attention. I will be happy to answer any questions you may have.

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Last revised: November 1, 2001