Key Points

In mainland France, June and July 2019 were marked by two widespread and intense heat waves. During these two episodes, for the first time since the implementation of the National Heat Wave Plan (PNC), mainland departments were placed under a red alert due to exceptionally high daytime temperatures.

Corsica was affected by the first national heatwave, which impacted Haute-Corse, but not by the second national heatwave. However, Southern Corsica was affected by a local heatwave from July 7 to 11. During periods when alert thresholds were exceeded:

• Heat-related conditions (defined by the iCanicule indicator, which includes hyperthermia, dehydration, and hyponatremia) accounted for up to 5.6% of emergency room visits and 3.4% of SOS Médecins calls per day during the first episode. More specifically, during the local episode, this activity accounted for a maximum of 1.8% of emergency room visits and 6.7% of SOS Médecins calls over a single day.

• The hospitalization rates following an emergency department visit during these two episodes were 54.2% and 43.6%, respectively.

• An estimated 14 [9–18] excess deaths occurred out of 46 expected deaths.

While the health impact of heat has increased significantly with rising temperatures, it was not limited to these periods alone, as three-quarters of emergency department visits and half of the SOS Médecins calls observed in Corsica occurred outside of these two heat waves. This highlights the importance of disseminating prevention messages throughout the summer season.