Monitoring Respiratory Syncytial Virus in Children Aged Five and Under Using Emergency Department and Urgent Care Center Chief Complaint Data in Florida's Syndromic Surveillance System , Week 1, 2010 - Week 50, 2013

BACKGROUND:   National studies estimate that RSV is responsible for one in 38 emergency department (ED) visits for children <5. The CSTE position statement (13-ID-07): “RSV-Associated Pediatric Mortality” advocates for improved RSV surveillance including  monitoring of RSV-associated pediatric mortality and hospitalizations to establish prevaccine baselines to evaluate vaccine effectiveness should one become available. Florida’s RSV surveillance relies on laboratory data reported in aggregate and calculation of percent positive.  Following national guidelines 10% or more for two consecutive weeks, denotes season onset. These data assess virus activity, and do not allow for assessment of morbidity or age specific analysis. Florida’s RSV seasonality differs from the nation; there is a year-round RSV season in some regions of the state. In Florida, pre-approval of prophylactic treatment by insurance companies is tied to seasonality. This analysis seeks to identify other effective and timely ways to monitor RSV and RSV-associated hospitalizations in children <5. 

METHODS:   Florida’s syndromic surveillance system (ESSENCE-FL) was used to identify the number of visits to EDs and urgent care centers (UCCs) with RSV listed as a chief complaint, discharge diagnosis or admission status (assessed through discharge disposition from the ED) for children under five between Week 1, 2010 and Week 50, 2013. Chief complaint data were available for all participating facilities (192), admissions data were available for most ESSENCE-FL participating facilities (171), and discharge diagnosis was available for some facilities. 

RESULTS:   A total of 10,370 visits were identified for RSV to EDs and UCCs; children <5 accounted for 10,170 (98%) of the visits; and children <1 year 7,969 (77%) of all visits. Of the 10,170 ED and UCC visits of children <5, 4614 (45%) resulted in hospital admission. Children <1 accounted for 3,784 (81%) of those admissions. Trend analysis showed that chief complaint and discharge diagnosis data in children <5 correlated with Florida’s RSV seasonality established using laboratory surveillance data populated by the weekly reporting of total tests and positive tests by hospital laboratories around the state.

CONCLUSIONS:   ED chief complaint data accessed through a syndromic surveillance system can be used for effective, timely monitoring of RSV hospitalizations in children <5 and may be a more efficient means of monitoring  seasonality of RSV activity statewide as compared to the manual reporting of laboratory data. Additionally, this surveillance technique can efficiently monitor RSV activity as well as estimate hospital admissions due to RSV and may be a useful approach for other states with syndromic surveillance systems.