CDC uses various data sources, including the National Syndromic Surveillance Program (NSSP), to monitor and inform the response to emerging health threats like avian influenza A(H5N1). NSSP gathers real-time electronic health records from more than 6,500 U.S. health care facilities, representing nearly 80% of emergency departments nationwide. These data help track flu symptoms and other health issues, offering early warning of unusual illness levels. CDC uses this information to assess flu activity, including potential increases that may be linked to H5N1, and supports local and national health responses with timely, actionable data.
Learn more at: How CDC Uses Emergency Department Data to Watch for Unusual Patterns of Flu Amid Concerns Over H5N1 Bird Flu.