Between 15 June and 19 July, a period during which Luxembourg experienced several heatwaves, the health authorities observed a significant rise in mortality. The available data show a particularly marked excess mortality among people aged over 75. The rise began during the week of 15 to 21 June. The peak was reached during the week of 29 June to 5 July. Following a brief decline, a spike was recorded in the week of 13 to 19 July. Data for the period since 19 July have not yet been compiled.

In Luxembourg, excess mortality – defined as the difference between the expected number of deaths and the number of deaths actually recorded – became statistically significant from the week of 15 to 21 June (week 25), a week during which an overall excess mortality of 8 people was observed. It was people aged over 75 who were affected. Whilst the normal statistical mortality rate for the 75–84 age group is 20 people, 26 deaths were recorded. For the 85+ age group, 35 deaths were recorded, compared with 29 under normal circumstances.

A rebound was observed between 13 and 19 July

The following week, from 22 to 28 June (week 26), excess mortality was estimated at 23 cases. Here too, it was the oldest people who bore the heaviest toll: 43 people aged over 85 died, 15 more than the statistical average. In the 75-84 age group, there were 28 deaths, 8 more than usual. The peak appears to have been reached during the week of 29 June to 5 July (week 27), with 106 deaths compared with an average of 74. This represents an excess mortality of 32 cases. Here too, the excess mortality affected the oldest age groups: 11 more deaths among those aged over 85 and 18 more cases in the 75-84 age group.

The following week – from 6 to 12 July – excess mortality fell, with an estimated 6 cases. All suspected deaths involved people aged over 85. In the week from 13 to 19 July, the health authorities observed a resurgence, with 18 cases. Data from the following weeks will help determine whether this resurgence has been contained.

However, these figures should be interpreted with caution. An increase in mortality observed during a heatwave does not mean that all deaths are directly attributable to the heatwave. As the minister for health pointed out, Martine Deprez (CSV), in its parliamentary response of 13 July, stated that deaths often occur in complex, multifactorial medical contexts. Heat may be an aggravating factor without being the sole cause of death.