Key Points

• The summer of 2021 was marked by a low-intensity heat wave in southeastern France in August and short-lived, localized spikes in June and July. Nine departments were affected by these episodes, representing 12% of the metropolitan population.

• An estimated 239 excess deaths (all causes combined) occurred during the heat waves in the affected departments, representing a relative excess mortality rate of +20%. People aged 75 and older were the most affected, with 204 excess deaths (+25%) in this age group.

• Over the course of the summer, nearly 2,500 SOS Médecins consultations and nearly 15,000 emergency room visits related to the iCanicule indicator (covering hyperthermia, heatstroke, dehydration, and hyponatremia) were recorded. More than half of the emergency room visits for iCanicule resulted in hospitalization, including 154 in intensive care or resuscitation units. People aged 75 and older accounted for 47% of emergency room visits and 32% of SOS Médecins consultations for iCanicule.

• No fatal workplace accidents potentially linked to heat were reported by the Occupational Health Inspection.

• These results underscore, even when the heat wave is short and mild, the importance of anticipating the impact of heat ahead of heat waves and reinforce the need for prevention measures tailored to the entire population, particularly the most vulnerable.

• During the same periods and in the same areas as the heat waves, 76 deaths linked to the COVID-19 pandemic were recorded, the vast majority of which were among people aged 70 and older. Thus, mortality linked to the COVID-19 pandemic cannot alone explain the excess mortality observed in areas affected by heat waves, even though the COVID-19 pandemic may have increased the vulnerability of certain populations to heat.