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2010 Report: Public Health Preparedness

Section 1: A National Snapshot of Public Health Preparedness Activities

Surveillance and Epidemiology: Monitoring and Investigating Health Threats

Surveillance and epidemiology are core public health functions that detect community health threats, investigate their sources and patterns of distribution, and monitor their impacts. These data are used to help in making decisions on actions meant to control or prevent disease or injury.

Surveillance: Data for Monitoring Health Threats

Public health surveillance is the ongoing, systematic collection, analysis, and interpretation of health data, and the dissemination of this information to those who need to know. Surveillance data may describe health problem trends, detect epidemics, provide details about disease patterns, monitor changes in disease agents like viruses (through working with laboratorians), help determine the most effective mitigation strategies, and evaluate the effects of control and prevention measures.

Public health officials use different types of surveillance data as a basis for decision making to protect the public’s health. One of the first examples of a public health action stemming from the use of surveillance data likely occurred during the bubonic plague in the 14th century, when authorities boarded ships to prevent passengers with plague symptoms from coming ashore. Many early surveillance systems were based on identifying and reporting cases of disease.

In the United States, surveillance systems are a collaborative effort between CDC and its many partners in state, local and territorial health departments; public health and clinical laboratories; vital statistics offices; healthcare providers; clinics; and emergency departments. These surveillance systems resources helped support decision making by public health officials during the 2009 H1N1 influenza pandemic response (see boxes below and on next page).

Flu View chart showing influenza disease activity throughout the United States

Surveillance resources such as FluView, CDC’s report on influenza disease activity, help support decision making by public health officials during outbreaks, including the 2009 H1N1 influenza pandemic.

Source: CDC

Current surveillance systems at the local, state, national, and international levels need to improve to meet the nation’s growing challenge to manage and integrate data from a variety of different sources, ensure that decision makers have access to the data, and exchange data with other federal agencies and with public health partners. In 2007, Homeland Security Presidential Directive 21 called for the development of a nationwide approach to enhance the United States’ ability to detect and respond to health-related threats. The National Biosurveillance Strategy for Human Health, an effort coordinated by CDC for the U.S. Department of Health and Human Services, provides a plan for building a nationwide, next-generation capability designed to generate timely, comprehensive, and accessible information for public health and clinical decision making.36 The Strategy established six priority areas: electronic health information exchange, electronic laboratory information exchange, unstructured data, integrated biosurveillance information, global disease detection and collaboration, and biosurveillance workforce.

Supporting the 2009 H1N1 Influenza Pandemic Response

CDC supported numerous resources that were critical for responding rapidly to the 2009 H1N1 influenza pandemic. Resources included support for domestic and global laboratory and surveillance systems; epidemiological and laboratory capacity and expertise; vaccine distribution and monitoring of the vaccination program; and communications, partnerships, and pandemic preparedness activities. These resources supported decisions at international, federal, state, and local levels aiming to slow the rapid spread of illness and limit morbidity and mortality.

Surveillance data and epidemiological investigations from the 2009 H1N1 influenza pandemic revealed that certain health conditions increased the risk of being hospitalized from 2009 H1N1 influenza. These conditions included lung diseases like asthma or chronic obstructive pulmonary disease, diabetes, heart disease, neurologic disease and pregnancy. Knowledge about these risks helped decision makers prioritize groups who would receive the first vaccines. The data also helped public health officials establish guidelines on antiviral treatment; how long people should stay home while ill; and the steps healthcare personnel, schools, businesses, community- and faith-based organizations, parents, and others needed to take to prevent infection.

Epidemiology: Investigating Health Threats

Epidemiologists – known as “disease detectives” – work closely with laboratorians to identify health threats, determine their patterns in a community, and estimate their effects. They might identify contaminated food causing illness, assess the number and locations of people injured and types of injuries resulting from a disaster, or determine causes of a sudden onset of fever in a community. Epidemiologists also work to minimize the negative effects of community health threats.

Detection depends on accurate and complete surveillance data. Problems can arise if data are not available, especially for state and local health agencies. In particular, health problems may not be identified early and public health interventions (e.g., the provision of treatments or vaccines) may be delayed.

Epidemiologists conduct targeted investigations and surveys that complement surveillance to validate and identify the causes and effects of a health event. Analyses of these data can produce criteria (e.g., specific symptoms) for determining whether a person should be counted as affected by the particular event, the characteristics of those affected (e.g., age, medication use, socioeconomic status), and the geographic extent of the event. Further studies help identify populations at increased risk for the disease or other health event.

Table 1: Epidemiological Capacity in the 50 States and the District of Columbia Health Departments; 2004-2009

  2004 2009 Percent
Number of epidemiologists working in state health departments 2,498 2,193 12%
Number of state health departments reporting substantial-to-full capacity in bioterrorism/emergency response 41 237 10%

Source: Council of State and Territorial Epidemiologists

CDC epidemiological support to states and localities for FY 2008 included 26 Career Epidemiology Field Officers (CEFOs) located in states and localities supported through state Public Health Emergency Preparedness (PHEP) funding. CDC also deployed 71 field officers from its Epidemic Intelligence Service (EIS) to conduct 319 investigations in the same year. EIS is a two-year epidemiology training program modeled on a traditional medical fellowship. Officers in this program support states during responses to routine public health incidents and large-scale national emergencies. CEFOs are experienced, fulltime epidemiologists located in state and local public health departments to enhance and build epidemiologic capacity for public health preparedness and response.

State epidemiological capacity continues to decline. A 2009 assessment37 by the Council of State and Territorial Epidemiologists reports that national epidemiological capacity has been eroding since 2004 (see Table 1). This trend contrasts with the significant increase in the number of epidemiologists that took place during 2001–2004, when emergency response and preparedness funds fueled rapid growth in the number of new and replacement epidemiologists in the public health workforce. The 2009 assessment also suggests that nearly 20% of current public health epidemiologists anticipate retiring or changing careers in the next 5 years and recommends that federal, state, and local agencies develop a strategy to address these projected downward trends and major gaps.

Enhancing Surveillance in Kansas to Assess Impact of the 2009 H1N1 Influenza Pandemic

Enhancing Surveillance in Kansas to Assess Impact of the 2009 H1N1 Influenza Pandemic
The Kansas Department of Health and Environment strengthened its surveillance capabilities to provide comprehensive state-level, regional, and local information on the impact of 2009 H1N1 influenza. Using resources from CDC’s Public Health Emergency Response funding, Kansas increased the number of sites in the Influenza-like Illness Surveillance Network statewide from 22 to 73. This one-time funding also supported the development of a hospital-based reporting system assessing hospitalization rates, a school absenteeism surveillance system, and comprehensive weekly surveillance and epidemiology reports that updated responders on the ongoing situation.

Source: Association of State and Territorial Health Officials (2010)

Assessing Capabilities for Surveillance and Epidemiology

CDC is developing performance measures related to surveillance and epidemiological capabilities. PHEP-funded states, localities, and U.S. insular areas will be required to report on measures that address the following:

  • Timely recognition of a potential health emergency through disease reports submitted to public health agencies
  • Ability to investigate an outbreak or exposure, summarize findings, and make improvements to the investigative process
  • Timeliness of initiating interventions to limit the spread of disease

The intent of these new measures is to demonstrate an ability to turn data into actionable information that supports decision making in a public health emergency. For more information on new performance measures, see the Moving Forward section.

Tracking the Impact of Hazardous Substance Incidents

The Hazardous Substances Emergency Event Surveillance system* works to reduce injury and death among first responders, employees, and the general public that result from releases of hazardous substances. By collecting data on hazardous substance releases and tracking subsequent health effects, it allows state public health officials to assess vulnerabilities and proactively plan for prevention and timely response. In FY 2008, this program tracked 8,150 hazardous substance incidents, 2,290 injuries, and 67 fatalities sustained in hazardous substance incidents, and 606 incidents that led to ordered evacuations of 48,464 people in 14 states.**

* As of September 30, 2009, the name of this program changed to the National Toxic Substance Incident Program. Seven states will be funded under the FY 2010 program announcement.

** The number of people evacuated does not include evacuees in incidents where a precise number is unavailable.

Source: CDC, Office for State, Tribal, Local and Territorial Support (2008)


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