摘要：Objectives. We assessed telephone surveys as a novel surveillance method, comparing data obtained by telephone with existing national influenza surveillance systems, and evaluated the utility of telephone surveys. Methods. We used the 2007 Behavioral Risk Factor Surveillance System (BRFSS) and the 2007 National Immunization Survey–Adult (NIS–Adult) to estimate the incidence of influenza-like illness (ILI), medically attended ILI, provider-diagnosed influenza, influenza testing, and treatment of influenza with antiviral medications during the 2006–2007 influenza season. Results. With the January–May BRFSS, among persons aged 18 years and older, the cumulative incidence of seasonal ILI and provider-diagnosed influenza was 37.9 and 5.7 adults per 100 persons, respectively. Monthly medically attended ILI and provider-diagnosed influenza among adults were temporally associated with influenza activity, as documented by national surveillance. With the NIS–Adult survey data, estimated provider-diagnosed influenza, influenza testing, and antiviral treatment were 2.8%, 1.4%, and 0.6%, respectively. Conclusions. Our telephone interview–based estimates of influenza morbidity were consistent with those from national influenza surveillance systems. Telephone surveys may provide an alternative method by which population-based influenza morbidity information can be gathered. Each winter in the United States, influenza season is marked by missed school and work days, increased medical visits, and for a relatively small but significant number of people, hospitalization and death. To monitor the annual disease burden of influenza, the Centers for Disease Control and Prevention (CDC) maintains a number of influenza surveillance systems that provide information about disease presence, geographic and temporal spread, severity of illness, type and subtype of the circulating influenza viruses, and unusual clinical manifestations of influenza by season. 1 Many infectious disease surveillance systems employed by public health are passive and rely on health care providers to report incident cases; other systems capitalize on existing data systems for surveillance purposes (e.g., vital statistics data) or employ special studies in limited populations. For practical reasons, only a subset of more severe influenza outcomes, such as those that involve an encounter with the public health or medical care system (e.g., hospitalization or outpatient visit), are routinely used to monitor influenza disease burden. Estimates of the total influenza burden on a community have been conducted in the past, but only as part of special studies. 2,3 The diagnosis and treatment of influenza in the United States requires access to medical care and delivery of services from health care providers. Influenza may be diagnosed by any of a number of laboratory tests. In most practice settings, influenza rapid tests are used as point-of-care diagnostic tool; although the specificity of these tests is high, 4 the sensitivity typically ranges from 50% to 70% 4 and may be as low as 11%. 5 Consequently, health care providers may also diagnose influenza on the basis of the patient’s clinical presentation, irrespective of influenza testing or test results, especially when influenza virus is circulating in the community. In 2006, the CDC, state health departments, and academic partners in 9 states that are members of the Emerging Infections Program Influenza Network developed a series of influenza morbidity questions as part of influenza pandemic planning activities. These questions, based on a previous influenza survey, 6 were designed to estimate the overall population burden of influenza by measuring the incidence of influenza-like illness (ILI), influenza diagnosed by a health care provider, use of influenza rapid testing, and treatment of influenza with antiviral medications during the 2006–2007 influenza season.
