Key Points

Following a gradual increase in COVID-19 cases in early February, the Île-de-France region experienced rapid community spread in March, with the epidemic peaking in week 13, from March 23 to 29. The impact of the epidemic was significant in the Île-de-France region. Residents of the region accounted for approximately 40% of Covid-19 deaths recorded in France since March 1, whether in hospitals or nursing homes. The lockdown was followed by a sharp decline in Covid-19-related healthcare utilization, first observed in outpatient settings during week 14, from March 30 to April 5, and then in hospitals starting April 7, continuing through week 24, from June 8 to 14—five weeks after the lockdown was lifted. This downward trend reversed in week 26.

Between weeks 27 and 32, most regional epidemiological indicators showed an increase in viral circulation in Île-de-France, particularly in Paris. In week 33 (August 10–16), a sharp increase in the incidence rate was observed, with the alert threshold (50 per 100,000 inhabitants) being exceeded in Paris (67.1 per 100,000), in Seine-Saint-Denis (50.7/100,000), and in Val-de-Marne (53.8/100,000). The rise in incidence accelerated in these last two departments during week 33. As for the positivity rate, it increased in the Île-de-France region (4.4%), with Seine-Saint-Denis and Val-de-Marne exceeding the 5% warning threshold. Most of those affected are between the ages of 20 and 40, particularly in Paris and the inner suburbs, which is linked to a significant number of clusters reported in the workplace. This finding highlights the importance of adhering to preventive measures in the workplace. Furthermore, a peak of over 140 cases per 100,000 inhabitants was observed among 20- to 30-year-olds in Paris and Val-de-Marne. This could indicate a relaxation of preventive measures, such as mask-wearing, among young people during gatherings. However, in week 32, a slight increase in incidence and positivity rates was observed among the elderly, which stabilized in week 33, along with a slight rise in the number of COVID-19 cases in long-term care facilities for the elderly during weeks 32 and 33. This trend should alert us to the need to protect at-risk individuals by maintaining preventive measures across the entire population. Indicators of emergency care and hospitalization use also continue to rise, though the increase remains relatively modest.

The return of residents of the Île-de-France region currently on vacation and the resumption of activities as the start of the school year approaches, as well as the significant proportion of people tested upon arrival at airports and counted in the Île-de-France region, should alert us to the need to maintain our efforts and remain vigilant. Adherence to preventive measures remains, at this time, the best way to reduce viral transmission.
This approach to risk reduction is all the more evident given that the summer season is associated with significant population movement and mixing, and is often accompanied by a desire to relax, resulting in reduced adherence to social distancing measures.