In Week 4 (January 24–30), the spread of SARS-CoV-2 slowed nationwide, with the incidence rate falling by 8%. However, this indicator continued to rise among people aged 70 and older and remained at a very high level (over 3,000 cases per 100,000 inhabitants) in most regions. Pressure on hospitals remained high, with hospital indicators still at very high levels, and the number of COVID-19 deaths—primarily among those aged 65 and older—continued to rise. Although it represents a minority of cases, the Omicron BA.2 sublineage, which is likely more transmissible, is gaining ground (2% in Week 3). As of February 1, 81.4% of those aged 65 and older had received a booster shot. This proportion was only 73.2% among those aged 80 and older. Strict adherence to preventive measures (wearing masks and limiting contact), frequent ventilation of enclosed spaces, and working from home remain essential to limit the number of infections. Stepping up vaccination efforts—including booster shots as early as three months after the initial dose, particularly among older adults—and adhering to all recommended measures in the event of symptoms, a positive test, or exposure to a high-risk contact are necessary to limit severe cases and ease the strain on the healthcare system, which remains under pressure.

Rise in incidence rate among those aged 70 and older

Nationally, after 15 weeks of increases, the incidence rate fell by 8% in week 4, reaching 3,460 cases per 100,000 inhabitants—still averaging more than 331,000 cases per day. It was declining among those under 50 and rising among those aged 70 and older. The sharpest increase was observed among those aged 90 and older (+19%). It remained highest among those aged 10–19. The testing rate (10,082/100,000) was down for the third consecutive week (-14%). The positivity rate continued to rise to 34.3%, though at a less pronounced rate than the previous week (+2.5 percentage points vs. +7.4 percentage points in Week 3). This continues to suggest a likely increase in the use of self-tests (not included in SI-DEP) subsequently confirmed by PCR or antigen testing. Data on case and contact tracing showed that the proportion of cases likely infected in a long-term care facility was rising again this week. This observation, along with the increase in infections among those aged 70 and older, calls for heightened vigilance regarding the epidemic’s progression among the elderly, particularly residents of these facilities.

In mainland France, the incidence rate was stable or declining in most regions amid a significant drop in testing rates. It fell the most in Île-de-France, the region with the lowest rate in week 4 (2,303, -30%).

In the overseas territories, incidence rates and rates of new hospitalizations decreased in all regions, but less markedly in Réunion, where the incidence rate remained above 5,000 (5,152/100,000, -5%) and the rate of new hospitalizations exceeded 40/100,000 (-11%).

Slight decrease in new hospital admissions and stabilization in critical care

In Week 4, the number of new hospitalizations was down slightly (-7%) while the number of admissions to critical care stabilized (-3%). The proportion of SARS-CoV-2-positive patients hospitalized for reasons other than COVID-19 rose to 32% in Week 4 for hospitalizations (vs. 30% in Week 3) and 18% (vs. 16%) for critical care. Nationally, the proportion of patients admitted for COVID-19 care with suspected Omicron infection reached 94% for conventional hospitalizations, 86% among patients requiring admission to critical care (including intensive care units), and 87% among patients who died. These proportions are similar to those observed among confirmed cases suspected of Omicron (99%).

• See Hospital Indicators on page 8.

In mainland France, rates of new hospitalizations remained stable or increased in most regions. The decline observed in Île-de-France in week 3 was confirmed. In the overseas territories, rates of new hospitalizations and new admissions to critical care were declining or stable in all regions. The highest rates of new hospitalizations were in Réunion (41.0/100,000), French Guiana (31.0), and Guadeloupe (26.3). The rates of new critical care admissions were highest in Réunion (5.5).

• Focus on severe COVID-19 cases admitted to intensive care on page 9.

Omicron suspected in over 99% of screening tests, with the BA.1 sublineage accounting for the vast majority

In Week 4, the proportion of samples with an A0C0 screening result was 99.4%, compared to 98.5% in Week 3. A screening result indicating the presence of one of Omicron’s target mutations was identified in 98.9% of interpretable results in Week 4. The proportion of screening results consistent with Omicron was very high in all regions of mainland France and overseas territories, with the proportion of A0C0 samples exceeding 98%.

Furthermore, sequencing data confirm the replacement of Delta by Omicron in mainland France: it accounted for 85% of interpretable sequences in the Flash S01 survey (01/03), compared to 93% and 97%, respectively, in the Flash S02 (01/10) and Flash S03 (01/17) surveys. To date, the vast majority of Omicron variants identified in France belong to the BA.1 sublineage. Among the interpretable sequences from the Flash surveys, the proportion of BA.1 and BA.2 was 81% and 0.2%, respectively, in week 1; 92% and 0.9% in week 2; and 95% and 2% in week 3. Preliminary international data suggest that BA.2 has a transmissibility advantage over BA.1, but their severity and ability to evade the immune response are believed to be similar. A comprehensive analysis is available in the variant risk analysis dated January 26, 2022.

More than 53% of the general population has received a booster dose

As of February 1, 2022, the estimated vaccination coverage in the general population based on Vaccin Covid was 78.6% for a complete primary vaccination series and 53.3% for the booster dose. Among those aged 18 and older, 67.2% had received a booster dose, and 77.5% of those eligible for the booster as of that date had actually received it. Among those aged 65 and older, 81.4% had received a booster dose, and 89.7% of those eligible for it as of that date had received it. In addition, 8.0% of children aged 10 to 11 had received a first dose of the vaccine (2.7% for those aged 5 to 9).

Regarding healthcare professionals, vaccination coverage for the booster dose was 72.3% (vs. 69.4% on January 25) for those working in nursing homes or long-term care facilities, 83.0% (vs. 81.4%) for private practitioners, and 70.9% for employees in healthcare facilities (vs. 68.2%).

In addition, Santé publique France has released an update on the surveillance of COVID-19 cases among healthcare workers and a summary of contact tracing activities.