Key Points

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

In the Centre-Val de Loire region, these two heatwave episodes caused alert thresholds to be exceeded in all departments during the first episode in June and during the second episode. On this occasion, two departments (Eure-et-Loir and Loiret) were placed on red alert (for two consecutive days) for the first time during the second episode. A significant impact on health was observed during these periods:

• During the periods when alert thresholds were exceeded and for the affected departments in the region, 158 [80–214] excess deaths were estimated, representing a relative excess mortality rate of +15.4%. The June heatwave alone accounted for 91 deaths. People aged 75 and older accounted for the majority of excess deaths: 116 deaths for the two episodes (relative excess mortality of 16.1%). However, relative excess mortality was higher among those aged 65–74: +27.9% (42 excess deaths).

• Heat-related conditions (defined by the iCanicule indicator, which includes hyperthermia, dehydration, and hyponatremia) accounted for 1.4% of emergency department visits and 1.5% of SOS Médecins calls during the first episode. During the second heatwave, this activity was lower, accounting for 0.9% of emergency room visits and 0.7% of SOS Médecins interventions. The hospitalization rate following an emergency room visit during these two episodes was 32.6% and 35.6%, respectively. While the impact was greater among those aged 75 and older, all age groups were affected.

The health impacts of the heat observed were not limited to these periods alone, as 60% of emergency room visits and 42% of SOS Médecins calls occurred outside of these two heat waves during the summer period (June 1 to September 15).