Key Points

• In Week 42, trends in virological indicators were mixed compared to the previous week. Given the shift in testing patterns following the removal of reimbursement for tests, these indicators should be interpreted with caution. The number of new hospitalizations and new admissions to critical care units increased after 8 weeks of decline followed by stability in Week 41. Circulation of the SARS-CoV-2 virus remained high in the region compared to other metropolitan areas. The stability of incidence in Week 42, against the backdrop of falling temperatures, widespread circulation of the Delta variant, declining public adherence to preventive measures, still-incomplete vaccination coverage—whose progress is slowing each week—and possible waning immunity over time calls for vigilant monitoring of all epidemiological indicators in the coming weeks.

• In Île-de-France, the regional incidence rate for week 42 was 71 cases per 100,000 inhabitants; it remained stable after seven consecutive weeks of decline followed by an increase in week 41. The stability of the incidence rate in the region masked disparities between departments and age groups. The testing rate continued the downward trend that began in week 33. This decline in testing accelerated across all departments due to the removal of reimbursement for tests, and the rate decreased by 20% in the region. The decline in testing reflected a decrease among people aged 15 and older, while it increased among those under 15. The positivity rate increased across all departments among people aged 15 and older. This rise in positivity was partly linked to the decrease in testing rates, but also to the resurgence of viral circulation, as the positivity rate continued to rise among symptomatic individuals, among whom testing rates remained stable.

• At the hospital level, the number of new hospitalizations of COVID-19 patients increased by +9% after 8 consecutive weeks of declines followed by stability in Week 41. The number of new critical care admissions rose again (+26%) after 6 weeks of decline. The number of reported deaths in hospitals fell by 21% (37 deaths in Week 42 vs. 47 deaths in Week 41).

• In Week 42, 75.3% of the Île-de-France population of all ages had received at least one dose of the vaccine, and 72.7% were fully vaccinated. However, the increase in vaccination coverage with at least one dose remained slow.

• Against the backdrop of schools and workplaces reopening, and with viral circulation remaining high, vaccinating all eligible individuals remains essential and must be combined with strict adherence to other preventive measures, particularly the use of protective barriers, limiting high-risk contacts, and self-isolation in the event of symptoms, a confirmed infection, or contact with a confirmed case. It is the combination of various individual and collective measures that helps limit the transmission of SARS-CoV-2 and can be decisive in reducing viral circulation and preventing severe cases and further strain on hospitals.