In Week 09 (February 28–March 6), SARS-CoV-2 transmission slowed only slightly (-7%) compared with the previous four weeks, suggesting that the incidence rate will plateau at a high level. The effective R number, although still below 1, rose to 0.81, and the positivity rate stabilized at a high level (1 in 5 tests was positive). The incidence rate remained above 500 cases per 100,000 inhabitants in most regions and rose sharply in Martinique, where it exceeded 2,400. An increase in the incidence rate was also observed among children aged 3–10. Hospital and intensive care admissions continued to decline, as did COVID-19-related mortality (fewer than 1,000 deaths). The BA.2 sublineage of the Omicron variant became the dominant strain nationwide in week 09. As of March 8, vaccination coverage remained generally stable compared to the previous week: 82.9% of those aged 65 and older and 74.3% of those aged 80 and older had received a booster shot. Given the continued high level of viral circulation, the start of the school year, and the easing of public health measures, it is essential to maintain preventive measures (wearing masks, handwashing, ventilating enclosed spaces) to limit the spread of the virus and protect the most vulnerable. A concerted effort must be made to administer booster shots to people aged 80 and older. Compliance with other measures—particularly in cases of symptoms, a positive test result, or exposure to a confirmed case—as well as participation in contact tracing remain essential.

The incidence rate remains high and is slowing its decline

Nationally, the incidence rate continued to decline in Week 09 but at a less pronounced rate than the previous week (-7% vs. -30% in Week 08). It remained at a high level with 546 cases per 100,000 inhabitants, or more than 52,000 new cases on average per day. This slight decrease was observed in all age groups, with the exception of 3- to 5-year-olds (+22%) and 6- to 10-year-olds (+11%). The testing rate (-8%) continued to decline across all age groups, with the exception—again—of 3- to 5-year-olds (+10%) and 6- to 10-year-olds (+3%), in connection with the start of the school year in academic zones A and B. The positivity rate stabilized at a high level (+0.1 percentage points).

In mainland France, the incidence rate was stable or declining in most regions. A slight increase was observed in Brittany (+9%) and Normandy (+8%). The testing rate was stable or declining across the entire country. In the overseas territories, the incidence rate adjusted for the effect of public holidays rose sharply in Martinique (2,449, +173%), as did the positivity rate (23.9%, +12.7 points), with an adjusted testing rate remaining very high (10,251, +28%). The incidence rate remained high in Réunion (954, -15%) and in Guadeloupe (680, +47%, adjusted rate).

Number of new hospitalizations and deaths continues to decline

Nationally, the decline in the number of hospital admissions (-22%) and intensive care admissions (-24%) continued. As of March 8, the number of hospitalized patients was below 22,000. The number of deaths in hospitals and long-term care facilities followed the same trend, with fewer than 1,000 deaths in week 09. As for excess mortality from all causes, the decline that began in week 06 continued more markedly in weeks 07 and 08.
In metropolitan France, rates of new hospitalizations continued to decline in all regions. In the overseas territories, the rate of new hospitalizations was declining in all regions except French Guiana, where it remained stable. The rate of new admissions to intensive care units was stable in all regions. These rates remained highest in Réunion.

The BA.2 sublineage of the Omicron variant is now dominant

Omicron accounted for more than 99.9% of interpretable sequences in the Flash S08 survey (02/21).
To date, four sublineages of the Omicron VOC have been detected in France: BA.1, its sublineage BA.1.1, BA.2, and BA.3.
As suggested by trends in previous weeks, the most frequently detected sublineage is now BA.2, accounting for 43% of the 2,929 Omicron sequences in the Flash S08 survey. According to preliminary data from Flash S09 (02/28), BA.2 is now the dominant variant, accounting for 52% of interpretable sequences. The BA.1 and BA.1.1 sublineages accounted for 22% and 34% of Omicron sequences in Flash S08. A total of 17 sequences corresponding to BA.3 had been identified as of March 7 (according to the EMERGEN database), including only two during Flash surveys and none since S06. The rise of BA.2 at the expense of BA.1 is observed throughout mainland France, but at varying levels across regions.

Since February 18, 2022, a Delta/Omicron recombinant (to which no lineage name has yet been assigned) has been subject to enhanced monitoring by the laboratories of the EMERGEN consortium, Santé publique France, and the CNR Virus des infections respiratoires. Detected in France, the reference sequence of this recombinant was published on GISAID on March 8, 2022. The majority of its genome corresponds to the Delta variant (sublineage AY.4), but a large portion of the S gene (encoding the Spike protein) corresponds to the Omicron variant (sublineage BA.1). As of March 8, 27 sequences of this recombinant have been detected in France, including 14 during Flash investigations. These sequences correspond to cases from several regions dating back to early January 2022, suggesting that this recombinant has been circulating at low levels for several weeks. To date, very little data is available on its characteristics, and investigations are ongoing. More information is available in the variant risk analysis dated February 23, 2021.

Nearly 75% of people aged 80 and older have received their booster shot, a level that remains insufficient

As of March 8, 2022, the estimated vaccination coverage in the general population based on Vaccin Covid was 79.4% for a complete primary vaccination series and 58.2% for the booster dose. Among those aged 18 and older, 72.8% had received a booster dose, and 82.6% of those eligible for the booster as of that date had actually received it. Among those aged 65 and older, 82.9% had received a booster dose, and 91.0% of those eligible for the booster as of that date had received it. Furthermore, 74.3% of those aged 80 and older had received a booster dose, and 87.4% of those eligible for the booster at that time had actually received it. This age group has the lowest booster dose vaccination coverage among all age groups aged 50 and older. A concerted effort must be made to vaccinate people aged 80 and older with the booster dose.

In addition, Santé publique France has published an update on contact tracing activities.