摘要：Objectives. The Minnesota Department of Health, in collaboration with the Centers for Disease Control and Prevention, implemented the Pertussis Active Surveillance Project to better understand pertussis epidemiology. We evaluated the program’s impact. Methods. Clinics in 2 counties were offered free diagnostic testing and an educational presentation covering pertussis epidemiology. Clinics were identified as either active or intermittent, with active clinics testing 33% or more of the total number of months enrolled. We used generalized estimating equations to assess changes in provider testing behavior over the project period. Results. Ninety-seven clinics enrolled, with 38% classified as active. Active clinics were more likely to use the state lab for diagnostic testing and had a larger staff. During the project period, a decline in days coughing at the time of visit occurred in both jurisdictions. Conclusions. Providing clinics with free diagnostic testing influenced their participation levels. Among active clinics, results suggest changes in provider testing behavior over the course of the project. However, given the lack of robust participation, this resource-intensive strategy may not be a cost-effective approach to evaluating trends in pertussis epidemiology. Pertussis, or whooping cough, is a communicable respiratory disease caused by the Gram-negative coccobacillus Bordetella pertussis . Although the disease is vaccine preventable, it remains endemic in the United States, with cyclical peaks occurring every 3 to 5 years. 1 Since the 1980s, incidence rates of pertussis have been rising in all age groups, 1–5 with adults and adolescents experiencing significant increases. 6 Paralleling national trends in pertussis activity, Minnesota reported a peak period in 2004 that continued into 2005 with an average yearly rate of 29.2 per 100 000 cases. A subsequent peak period started in 2008 that continued into 2010 with an average annual rate of 20.9 per 100 000 cases. 7 Minnesota experienced a shift in the median age between these 2 peak periods, from 13 to 11 years. Although reportable in all states, pertussis frequently goes unrecognized. 4,8–10 Provider knowledge regarding pertussis epidemiology and clinical practice is inconsistent, limiting the reliability of passive surveillance systems to accurately capture disease incidence. 11 The natural progression of the disease, beginning with nonspecific upper respiratory system symptoms and ending with a persistent paroxysmal cough, creates an ambiguous clinical picture for the purpose of diagnosis. 5,12 This is especially true for adults and adolescents, in whom disease presentation may be mild, atypical, or difficult to differentiate from other upper respiratory tract infections. 4,8,11–13 Studies have indicated that 12% to 32% of adults and adolescents with a cough of unknown etiology lasting 1 to 2 weeks are seropositive for pertussis. 14 For these reasons, national and statewide estimates of pertussis incidence may be greatly underestimated. 6,11,15,16 In an effort to address the issues around provider awareness and underreporting of pertussis, the Minnesota Department of Health (MDH) collaborated with the Centers for Disease Control and Prevention and 2 local public health agencies on an initiative to increase recognition and testing of suspect pertussis cases through education and free pertussis testing incentives. This initiative, the Pertussis Active Surveillance Project (PASP), ran from 2005 to 2009 (51 months total). We report here the results of a program evaluation of PASP, focusing on the factors associated with clinic participation and changes in provider testing behavior over time.
