The U.S. fully implemented the International Health Regulations and submitted 59 potential Public Health Emergencies of International Concern (PHEIC) to WHO since 2007. The 2009 H1N1influenza pandemic, first notified as required notification of a novel strain of influenza by the U.S., is the only event determined to be a PHEIC by WHO to date. The public health impact of information sharing of PHEICs on a secure IHR website or of direct exchanges between trusted IHR National Focal Points is not known. However, a shared platform and assessment tool has facilitated notifications across national borders.