Background: The Pennsylvania Department of Health (PA-DOH) conducts Influenza-like-Illness (ILI) surveillance through a network of volunteer physician practices enrolled in the Outpatient Influenza-like Illness Surveillance Network (ILINet). One objective of ILINet is to monitor the burden of ILI as a proxy for community Influenza activity. Weekly, participants submit aggregate data on patients with ILI; these data are evaluated the following Monday for CDC notification.
Objectives: To evaluate reporting frequency and timeliness of data submitted by providers to the Pennsylvania ILINet system during the 2005/06-2009/10 flu seasons.
Methods: Reporting frequency was calculated for each provider using the number of weeks they submitted data and were enrolled in ILINet each flu season. Timeliness was assessed by calculating the percent of ILINet reports received by Monday each week.
Results: Of 146 providers currently participating in ILINet, 104 (71%) enrolled after the 2007/08 flu season. While the absolute number of providers reporting to ILINet at least 50% of the time has increased each year, the proportion of providers this represents has declined over the period: 2005/06 flu season: 25/29 (86% of enrolled providers reported 50% of the time); 2006/07: 34/41 (83%); 2007/08: 34/43 (79%); 2008/09: 62/126 (49%); 2009/10: 63/146 (43%). Among all providers, 32 (20%) have never reported data since enrollment. Timeliness has generally increased over time: 2005/06: 20%; 2006/07: 29%; 2007/08: 20%; 2008/09: 34%; 2009/10: 41%.
Conclusions: While total enrollment in ILINet and timeliness of data submission have improved over time, the proportion of providers submitting weekly reports has declined. Improved outreach and feedback is needed to encourage improved reporting of ILINet data and participation in the system. Consideration of reporting quality is needed to properly interpret ILINet trends and findings.