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 Île-de-France. Residents of Île-de-France 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 decrease in Covid-19-related healthcare utilization. First observed in outpatient care during week 14, from March 30 to April 5, and then in hospitals starting April 7, this trend continued 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 34 (August 17–23), the incidence rate continued its exponential rise, with 65 new cases per 100,000 residents and 94 in Paris, compared to 46 and 71 the previous week, respectively. The alert threshold (50) was thus exceeded in the inner suburbs and the Val-d’Oise department.

Young adults aged 20–30 stood out with a virus circulation rate four times higher than in all other age groups combined. This trend was observed in all departments but was most pronounced in Paris (240 new cases per 100,000 residents aged 20–30 in week 34), followed by the inner suburbs and Val-d’Oise.

Although less dramatic, the increase in incidence was seen across all age groups, with the slowest rise occurring among the elderly (>70 years old), who are evidently protected by fewer social contacts and perhaps by better adherence to preventive measures. There are concerns about the impact this fall of increased social mixing as schools reopen.
Lagging several weeks behind test-based indicators, the trend in hospital indicators has remained limited to the early stages of a resurgence. However, the number of hospitalized patients returning home is already being outpaced by new admissions, a situation not seen since late April. This unfavorable trend appears to have spared social and medical-social facilities (including nursing homes), indicating that the protective and distancing measures implemented there are effective.

Ultimately, it appears that the measures put in place are potentially and occasionally effective—such as the widespread lockdown or the measures taken in nursing homes—but have failed to contain the epidemic in the general population following the summer vacation. The coming weeks are unlikely to be favorable, and this outlook raises questions about prevention efforts in France as well as in other European countries.