Key Points

• In the Hauts-de-France region, 10,771 new cases of SARS-CoV-2 infection were diagnosed from January 4 to 10 (compared to 8,187 cases from December 28, 2020, to January 3, 2021), representing a 32% increase in new cases during the first week of January 2021. The incidence rate (IR) rose last week at the regional level. The positivity rate is also on the rise, once again exceeding 5%, against a backdrop of an overall increase in the testing rate (+17% at the regional level compared to the previous week).

• Over the last 7-day rolling period, the regional effective reproduction number, estimated based on the trend in the number of newly diagnosed cases, is rising this week and, once again, significantly above 1: R-eff = 1.22 [1.20–1.24]. The value of this epidemic dynamics parameter, which is significantly greater than 1, confirms the active resurgence of the epidemic in the region.

• The spread of the epidemic is affecting all age groups, particularly the working-age population (20–49 years). We must remain vigilant regarding trends in this age group over the coming weeks as school, university, professional, and social activities resume. The incidence rate, which had been declining among people over 65, began rising again last week.

• As of January 4, 2021, five cases of infection caused by the new British variant have been identified in residents of Hauts-de-France and confirmed by the National Reference Center (CNR) for Influenza and Respiratory Viruses (Institut Pasteur, Paris). Investigations have revealed a direct or indirect link to the United Kingdom (travel or high-risk contact with a person returning from the United Kingdom) for 4 of the 5 identified cases.