Key Points 

Extreme Heat, Heat Wave

• The heatwave, which affected all of France, began in the Provence-Alpes-Côte d’Azur region on June 22, 2026. In total, it affected five departments: Alpes-de-Haute-Provence, Alpes-Maritimes, Bouches-du-Rhône, Var, and Vaucluse. Since June 27, three departments have been under an orange heat wave alert: Alpes-de-Haute-Provence, Alpes-Maritimes, and Var.

Dengue, Chikungunya, and Zika

• Since the start of enhanced surveillance (May 1), 37 imported cases have been identified in the region: 11 cases of chikungunya (+2 compared to last week) and 26 cases of dengue (+3).
• The import pressure is much lower than it was during the same period in 2025.
• No locally acquired cases have been detected in mainland France.

West Nile Virus Infections

• No locally acquired cases have been detected in mainland France since the start of enhanced surveillance (May 1).

Pollen and Allergies 

• Pollen levels were high in the Provence-Alpes-Côte d’Azur (PACA) region. Allergy-related activity at SOS Médecins remained stable this week, at a low level for the season.

Reportable Diseases

• In the Provence-Alpes-Côte d’Azur (PACA) region, 35 reports were recorded in May 2026, including 23 cases of Legionnaires’ disease, 7 cases of hepatitis A, 3 cases of invasive meningococcal disease, 2 cases of measles, and no cases of foodborne illness.

Mortality

• The weekly number of deaths from all causes remains within the usual range of fluctuation in Week 25 (the week preceding the start of the heat wave). 
• Electronic death certificate data show a slight increase in deaths in Week 26 compared to Week 25 (+11%, within the usual range of fluctuation). This indicator, which still needs to be validated, should be interpreted with caution.