The National Heat Wave Plan (PNC) aims to anticipate the onset of a heat wave, define the actions to be implemented at the local and national levels to prevent and limit its health impacts, and tailor prevention and management measures as effectively as possible at the regional level, with particular attention to specific populations. Decisions by public authorities regarding the adaptation of PNC levels in each department are based on the meteorological risk assessment conducted by Météo-France and the health risk assessment by the French Institute for Public Health Surveillance.

As part of its public health monitoring, surveillance, and alert missions, the French Institute for Public Health Surveillance monitors various health indicators during heat waves, based on data provided by partners participating in the SurSaUD® system (hospital emergency departments, SOS Médecins, INSEE).

The indicators routinely monitored to assess the impact of heat waves are:

Visits to emergency departments in the OSCOUR® network:

• visits for all causes, all ages, and among people aged 75 and older,

• visits for heat-related conditions across all ages (hyperthermia/heatstroke, dehydration, hyponatremia),

• visits for asthma (in the event of a peak in ozone pollution coinciding with the heat wave).

Consultations at SOS Médecins clinics:

• consultations for all causes and all ages,

• consultations with heat-related diagnoses (heatstroke, dehydration) for all ages,

• consultations with asthma diagnoses (in the event of a spike in ozone pollution coinciding with a heatwave).

All-cause mortality for all ages and by age group recorded by a sample of municipalities covering the entire country and accounting for nearly 70% of total mortality in France.

This bulletin presents a summary of this surveillance for the summer of 2015.