Influenza Significant Case Reporting Form Evaluation

BACKGROUND: During the first wave of the 2009 H1N1 pandemic, the Massachusetts Department of Public Health Bureau of Infectious Disease (BID) implemented a clinician-based reporting form to collect demographic, clinical, and risk information on laboratory confirmed cases. This information helped to describe the population infected and identify individual cases at higher risk of severe illness or transmission. The form was sent to ordering providers of laboratory-confirmed cases of influenza and returned via FAX through an automated image capture and data processing system (TeleForm) directly into the state electronic disease surveillance system (MAVEN). We assessed the ongoing utility of the form for seasonal influenza by evaluating return rate, timeliness, completeness, and cost during the pandemic and in subsequent seasons.

METHODS:  5,464 influenza case records reported for the 2009 through 2013 seasons were extracted from MAVEN with variables indicating form sendout/receipt status and corresponding dates as well as key case investigation variables (Pregnancy Status, Hospitalization, and Outcome).  Return rates and timeliness (days to return) were then calculated and aggregated by season.  Variable completeness was assessed as Present, Missing, or Unknown and aggregated by season.  Maintenance and processing costs (postage, materials, staff) were estimated through time-tracking (1 month) and published material costs.

RESULTS: During the first wave of the pandemic 62% of forms mailed out were returned. In subsequent seasons, including the second wave of the pandemic, fewer than 50% of forms were returned. The low return rate was independent of the severity of the season. Overall, 30% of forms were returned within one week of mailing and 69% after 1 week or more. Among returned forms, completeness of key variables was high (80-98%) for all seasons evaluated. Maintenance of the system required 237 hours of MDPH staff time with an estimated cost per mailing of $1.13, in addition to time invested by epidemiologists reviewing high risk cases.

CONCLUSIONS: Despite highly complete information among those forms returned, the poor return rate lessened the utility of these data for comprehensive analysis. The delay in receipt by BID was determined by the program to be prohibitive for effective intervention or meaningful situational awareness beyond other available surveillance data sources. Given the significant time and resources necessary to sustain the data stream, MDPH decided to discontinue use of the form for seasonal influenza, but keep the system available for rapid deployment in the case of a future pandemic or novel strain.