Samuel Stebbins

Low sensitivity of rapid diagnostic test for influenza

The QuickVue Influenza A+B Test (Quidel) was used to test nasal swab specimens obtained from persons with influenza-like illness in 3 different populations. Compared with reverse-transcriptase polymerase chain reaction, the test sensitivity was low for all populations (median, 27%; range, 19%-32%), whereas the specificity was high (median, 97%; range, 96%-99.6%).

Simulating School Closure Strategies to Mitigate an Influenza Epidemic

BACKGROUND There remains substantial debate over the impact of school closure as a mitigation strategy during an influenza pandemic. The ongoing 2009 H1N1 influenza pandemic has provided an unparalleled opportunity to test interventions with the most up-to-date simulations. METHODS To assist the Allegheny County Health Department during the 2009 H1N1 influenza pandemic, the University of Pittsburgh Models of Infectious Disease Agents Study group employed an agent-based computer simulation model (ABM) of Allegheny County, Pennsylvania, to explore the effects of various school closure strategies on mitigating influenza epidemics of different reproductive rates (R0). RESULTS Entire school system closures were not more effective than individual school closures. Any type of school closure may need to be maintained throughout most of the epidemic (ie, at least 8 weeks) to have any significant effect on the overall serologic attack rate. In fact, relatively short school closures (ie, 2 weeks or less) may actually slightly increase the overall attack rate by returning susceptible students back into schools in the middle of the epidemic. Varying the illness threshold at which school closures are triggered did not seem to have substantial impact on the effectiveness of school closures, suggesting that short delays in closing schools should not cause concern. CONCLUSIONS School closures alone may not be able to quell an epidemic but, when maintained for at least 8 weeks, could delay the epidemic peak for up to a week, providing additional time to implement a second more effective intervention such as vaccination.

Research findings from nonpharmaceutical intervention studies for pandemic influenza and current gaps in the research.

In June 2006, the Centers for Disease Control and Prevention released a request for applications to identify, improve, and evaluate the effectiveness of nonpharmaceutical interventions (NPIs)-strategies other than vaccines and antiviral medications-to mitigate the spread of pandemic influenza within communities and across international borders (RFA-CI06-010). These studies have provided major contributions to seasonal and pandemic influenza knowledge. Nonetheless, key concerns were identified related to the acceptability and protective efficacy of NPIs. Large-scale intervention studies conducted over multiple influenza epidemics, as well as smaller studies in controlled laboratory settings, are needed to address the gaps in the research on transmission and mitigation of influenza in the community setting. The current novel influenza A (H1N1) pandemic underscores the importance of influenza research.

Reduction in the Incidence of Influenza A But Not Influenza B Associated With Use of Hand Sanitizer and Cough Hygiene in Schools A Randomized Controlled Trial

Background: Laboratory-based evidence is lacking regarding the efficacy of nonpharmaceutical interventions (NPIs) such as alcohol-based hand sanitizer and respiratory hygiene to reduce the spread of influenza. Methods: The Pittsburgh Influenza Prevention Project was a cluster-randomized trial conducted in 10 elementary schools in Pittsburgh, PA, during the 2007 to 2008 influenza season. Children in 5 intervention schools received training in hand and respiratory hygiene, and were provided and encouraged to use hand sanitizer regularly. Children in 5 schools acted as controls. Children with influenza-like illness were tested for influenza A and B by reverse-transcriptase polymerase chain reaction. Results: A total of 3360 children participated in this study. Using reverse-transcriptase polymerase chain reaction, 54 cases of influenza A and 50 cases of influenza B were detected. We found no significant effect of the intervention on the primary study outcome of all laboratory-confirmed influenza cases (incidence rate ratio [IRR]: 0.81; 95% confidence interval [CI]: 0.54, 1.23). However, we did find statistically significant differences in protocol-specified ancillary outcomes. Children in intervention schools had significantly fewer laboratory-confirmed influenza A infections than children in control schools, with an adjusted IRR of 0.48 (95% CI: 0.26, 0.87). Total absent episodes were also significantly lower among the intervention group than among the control group; adjusted IRR 0.74 (95% CI: 0.56, 0.97). Conclusions: NPIs (respiratory hygiene education and the regular use of hand sanitizer) did not reduce total laboratory-confirmed influenza. However, the interventions did reduce school total absence episodes by 26% and laboratory-confirmed influenza A infections by 52%. Our results suggest that NPIs can be an important adjunct to influenza vaccination programs to reduce the number of influenza A infections among children.

Local Spatial and Temporal Processes of Influenza in Pennsylvania, USA: 2003–2009

Background Influenza is a contagious respiratory disease responsible for annual seasonal epidemics in temperate climates. An understanding of how influenza spreads geographically and temporally within regions could result in improved public health prevention programs. The purpose of this study was to summarize the spatial and temporal spread of influenza using data obtained from the Pennsylvania Department of Healths influenza surveillance system. Methodology and Findings We evaluated the spatial and temporal patterns of laboratory-confirmed influenza cases in Pennsylvania, United States from six influenza seasons (2003–2009). Using a test of spatial autocorrelation, local clusters of elevated risk were identified in the South Central region of the state. Multivariable logistic regression indicated that lower monthly precipitation levels during the influenza season (OR = 0.52, 95% CI: 0.28, 0.94), fewer residents over age 64 (OR = 0.27, 95% CI: 0.10, 0.73) and fewer residents with more than a high school education (OR = 0.76, 95% CI: 0.61, 0.95) were significantly associated with membership in this cluster. In addition, time series analysis revealed a temporal lag in the peak timing of the influenza B epidemic compared to the influenza A epidemic. Conclusions These findings illustrate a distinct spatial cluster of cases in the South Central region of Pennsylvania. Further examination of the regional transmission dynamics within these clusters may be useful in planning public health influenza prevention programs.

Local Variations in Spatial Synchrony of Influenza Epidemics

Background Understanding the mechanism of influenza spread across multiple geographic scales is not complete. While the mechanism of dissemination across regions and states of the United States has been described, understanding the determinants of dissemination between counties has not been elucidated. The paucity of high resolution spatial-temporal influenza incidence data to evaluate disease structure is often not available. Methodology and Findings We report on the underlying relationship between the spread of influenza and human movement between counties of one state. Significant synchrony in the timing of epidemics exists across the entire state and decay with distance (regional correlation = 62%). Synchrony as a function of population size display evidence of hierarchical spread with more synchronized epidemics occurring among the most populated counties. A gravity model describing movement between two populations is a stronger predictor of influenza spread than adult movement to and from workplaces suggesting that non-routine and leisure travel drive local epidemics. Conclusions These findings highlight the complex nature of influenza spread across multiple geographic scales.

Household transmission of influenza A and B in a school-based study of non-pharmaceutical interventions

The effect of school-based non-pharmaceutical interventions (NPIs) on influenza A and B transmission in childrens households has not been estimated in published literature. We use data from a large school-based cluster randomized trial of improved hand and respiratory hygiene measures to explore the secondary transmission of influenza A and B in households of laboratory confirmed influenza cases. Data were taken from the Pittsburgh Influenza Prevention Project, a cluster-randomized trial of NPIs conducted in ten Pittsburgh, PA elementary schools during the 2007-2008 influenza season. We estimated two measures of influenza transmissibility in households; the susceptible infectious transmission probability, using variants of the Reed-Frost chain binomial model, and the secondary attack rate. We identified predictors of ILI using a logistic generalized estimating equation model. We estimate the secondary attack rates in intervention households to be 0.26 (95% confidence interval (CI) 0.19-0.34) compared to 0.30 (95% CI 0.23-0.38) in control households. Race and age were significant risk factors for secondary ILI acquisition in this study. We found no significant differences between the transmission probabilities for infectious individuals in intervention (0.19, 95% CI 0.14-0.25), and control households (0.22, 95% CI 0.16-0.29). Similarly, estimates for secondary attack rates and transmission probabilities for households with confirmed influenza A (0.31 and 0.22) were not significantly different from estimates from households with confirmed influenza B (0.25 and 0.20). While influenza A and B are thought to have different transmission characteristics, we find no significant differences in their transmissibility within households. Though our results suggest a potential effect, we found no statistically significant effect of school-based non-pharmaceutical interventions on transmission in symptomatic childrens homes.

Public Health Area of Concentration: a model for integration into medical school curricula.

Calls for more public health education for medical students date back at least 150 years. In recent years, medical schools have increased their required coursework in core public health topics such as epidemiology, biostatistics, and behavioral determinants of health. Some schools have created more in-depth alternatives, including combined or concurrent masters degrees; MD/PhD programs with a public health track; certificates in public health; or complete re-envisioning of the school into an integrated medical and public health institution. In 2009 the University of Pittsburgh School of Medicine began a Public Health Area of Concentration (AOC) that provides an optional, integrated curriculum that includes key elements of research, practice, and leadership. The AOC is a partnership between two schools at the University of Pittsburgh--Medicine and Public Health--and the local county health department. The result is a program that provides mentorship and training over 4 years of education designed to mend the long historical divide between the skills and constituencies of individual and population health. In addition, the AOC is relatively easy and inexpensive to implement and is modular in nature. The Public Health AOC is a simple model for incorporating many key aspects of public health into medical education and can be duplicated by any university that is willing to create partnerships and work across boundaries.

Developing a measure of local agency adaptation to emergencies: a metric.

Local public health agencies often must respond to health-related emergencies or disasters, while continuing to fulfill all public health functions for which they are funded. This article reports the development and initial pilot test of a method for measuring the nature and degree of a public health agencys response to such an emergency or disaster. How the instrument was developed as well as the initial results from the pilot study of four local public health systems (LPHSs) are presented and discussed. The instrument measured the extent to which each function and division of each of the four LPHSs were affected and provided a metric that could be used across LPHSs to indicate the burden experienced by each due to the emergency. Results obtained from the pilot study indicate that size and complexity of an LPHS was not predictive of its ability to respond to the emergency. These results support the use of the framework and associated measurement procedures to provide valuable information to managers responsible for such LPHSs. Such information should provide a foundation for comparing variations in performance and outcomes to various types of emergencies that vary in their severity and focus.

Sensitivity and specificity of rapid influenza testing of children in a community setting.

Please cite this paper as: Stebbins et al. (2011) Sensitivity and specificity of rapid influenza testing of children in a community setting. Influenza and Other Respiratory Viruses 5(2), 104–109.