Following the heat wave of summer 2003, a national heat wave plan was implemented in 2004. This plan outlines preventive measures and care protocols for individuals in the event of a heat wave. It is based on a heat wave and health alert system developed by the Institute for Public Health Surveillance, in collaboration with Météo-France. In 2006, the heat wave plan was renewed and simplified, with three intervention levels instead of four. Thus, the seasonal monitoring level—formerly Level 1—is in effect from June 1 through August 31. A forecast of threshold exceedance and/or the actual exceedance of thresholds for biometeorological indices triggers, following an analysis of associated qualitative criteria, a transition to the warning and action level (MIGA)—formerly levels 2 and 3. The maximum mobilization level—formerly level 4—is activated during a severe crisis. Alerts are proposed by the French Institute for Public Health Surveillance—after consultation with Météo-France—and issued by the departmental prefect. In parallel with the monitoring of biometeorological data, a system for collecting and analyzing emergency department activity data, as well as monitoring deaths recorded by the civil registry offices of sentinel municipalities, has been established in the regions. In 2006, morbidity indicators for Upper Normandy were automatically collected from the region’s 20 emergency departments, 3 emergency medical services, and 2 departmental fire and rescue services via the Regional Hospitalization Agency’s IT platform, which had been in place since July 2005. Deaths recorded by the civil registry offices of the region’s computerized municipalities were transmitted by the National Institute of Statistics and Economic Studies to the Institute for Health Surveillance. During the 2006 seasonal surveillance period, a severe heat wave was observed during the second half of July in the vast majority of French regions and in Upper Normandy. However, the warning and action level was not triggered in the region during the monitoring period: - Biometeorological index thresholds were not reached or exceeded in Upper Normandy, even at the height of the national heatwave in July; - Activity among the region’s emergency services was, overall, higher than in 2005 (+7%), with a 14% increase in activity in July. Nevertheless, this particularly high level of activity among health services could not be directly linked to one or more environmental indicators capable of triggering a health crisis (heat, sunshine, pollution, etc.). It should also be noted that, mirroring the overall activity of the region’s emergency services, activity specifically related to vulnerable populations was higher in 2006 than in 2005, particularly in July: a 37% increase compared to July 2005 for children under one year of age and a 15% increase for adults over 75 years of age. The hospitalization rate remained stable, confirming the observations of emergency physicians who reported a higher influx of minor cases. Finally, the monitoring process helped improve these tools for forecasting health alerts. In particular, this monitoring enabled: - Consolidating the network for monitoring emergency department activity in the region; - Diversify communication tools for providing feedback to partners; - Improve the analysis of morbidity indicators, notably by recalculating the alert thresholds for these indicators; - Establish monitoring of mortality indicators; - Initiate discussions on fluctuations in activity based on time periods, services, target populations, days of the week, or specific events...