Key Points

• In Week 44, the incidence rate of new SARS-CoV-2 infections increased in Île-de-France compared to the previous week. Given the shift in testing patterns associated with the end of reimbursement for tests and school holidays, this indicator should be interpreted with caution: a slight underestimation cannot be ruled out. The increase in the positivity rate among symptomatic individuals confirmed the resurgence of SARS-CoV-2 circulation observed in the region since Week 41. Against a backdrop of renewed social contact, reduced adherence to preventive measures, incomplete vaccination coverage—particularly among children—potential waning of immunity over time, and falling temperatures, all indicators must be closely monitored in the coming weeks.

• In Week 44, the crude incidence rate among residents of Île-de-France increased after two weeks of relative stability: it stood at 83 cases per 100,000 inhabitants (vs. 74 per 100,000 in Week 43). This increase in incidence in the region masked disparities between departments and across age groups. The adjusted regional incidence rate—which accounts for the decline in testing due to the November 1 holiday—reached 94 cases per 100,000 inhabitants.

• The testing rate continued the downward trend that began in Week 33 at the regional level and across all departments in the Île-de-France region. This testing rate decreased for all age groups under 65 and remained stable among those aged 65 and older.

• The positivity rate increased slightly in week 44 in the region and in most departments of the Île-de-France region. It remained stable among people aged 75 and older, while it increased slightly in other age groups. The rise in positivity continued among symptomatic individuals.

• For week 44, data extracted as of November 9, 2021, shows a 5% decrease in weekly new hospitalizations and a 5% decrease in critical care admissions, while new deaths showed an apparent decrease of 18%. It is likely that this apparent decrease constitutes—for the second consecutive week—an artifact of underreporting. This phenomenon is linked to a period of reduced hospital staff allocated to SIVIC data entry, amid staff leave and a bronchiolitis epidemic involving a reallocation of resources to pediatric hospital departments.

• In Week 44 in Île-de-France (data by date of injection and vaccination site), vaccination coverage for at least one dose of the SARS-CoV-2 vaccine was 76.0% (compared to 75.7% in Week 43) and 73.5% (compared to 73.2% in Week 43) for the full vaccination series. The increase in vaccination coverage remained low.

• Given the high and rising viral circulation, vaccinating all eligible individuals remains essential and must be combined with high adherence to other preventive measures, particularly adherence to barrier measures, 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 SARS-CoV-2 transmission and can be decisive in reducing viral circulation and preventing severe cases, renewed strain on hospitals, and even the emergence of new variants.