Incidence rates remained highest among those aged 10–39, and the increase compared to the previous week was mainly observed among those aged 40 and older, reflecting the spread of the outbreak from younger to older age groups. The impact of this fourth wave on hospital admissions continues, although the increase in new hospitalizations and admissions to intensive care units was less pronounced than in the previous week. In the overseas territories, the situation is very concerning in Guadeloupe and Martinique. Contact tracing data indicate poorer identification of contacts and transmission chains during this summer period.

In France, as of August 10, 2021, 67.4% of the population had received at least one dose of the vaccine, and 56.4% were fully vaccinated. In this context, vaccination of all eligible individuals must continue to be strongly encouraged to achieve a sufficient level of herd immunity and must be combined with high adherence to other preventive measures, particularly compliance with barrier measures, limiting high-risk contacts, and self-isolation in the event of symptoms, a confirmed infection, or contact with a confirmed case. The combination of accelerated vaccination and various measures to limit transmission rates can have a significant impact on hospitalization trends.

Increase in incidence rates among those aged 40 and older

Nationally, the incidence rate in week 31 was 236 per 100,000 inhabitants, with a more moderate increase (+4%), resulting in a declining reproduction number (1.07 vs. 1.27 in week 30). The highest rate was still among those aged 20–29 (505, -13%), and the increase was observed most notably among those aged 40 and older. The testing rate, including antigen and PCR tests (excluding self-tests), remained high at 5,473 per 100,000 inhabitants, stable in Week 31. The positivity rate was comparable to that of Week 30: 4.3%, an increase of 0.1 percentage points.

In mainland France, the highest incidence, positivity, and testing rates were observed in Corsica, Provence-Alpes-Côte d’Azur, and Occitanie: incidence rate in Corsica (630/100,000, -4%), Provence-Alpes-Côte d’Azur (590, +3%), and Occitanie (413, -2%). The change in the incidence rate compared to Week 30 ranged from -11% (Nouvelle-Aquitaine) to +21% (Hauts-de-France). In the overseas territories, the situation is very concerning in Guadeloupe and Martinique. The incidence rate was very high, reaching 1,893 per 100,000 (+116%) in Guadeloupe and 1,181 (+8%) in Martinique.

The number of hospitalized patients continues to rise

In hospitals, although less pronounced, the rise in indicators continued, with 4,764 new hospitalizations in Week 31 (+35% vs. +92% in Week 30) and 1,086 new admissions to intensive care (+46% vs. +98% in Week 30). Still on the rise, the number of COVID-19 patients currently hospitalized reached 9,213 (+15%), including 1,725 (+28%) in critical care units. COVID-19-related deaths (in hospitals and long-term care facilities) were on the rise (347, +28%).

In mainland France, hospitalization rates by admission date as of August 10 continued to rise in all regions except Corsica. The highest rates were in Provence-Alpes-Côte d’Azur (15.8/100,000), Corsica (14.6), and Occitanie (11.0). In the overseas territories, hospitalization rates were rising sharply. In Martinique, excess mortality from all causes and across all age groups was observed in week 30. The incidence rate remained high in Réunion (397, +1%) and French Guiana (260, +23%).

• See the epidemiological update: Weekly Focus—data on incidence by age group and region, as well as hospitalizations by admission date, age group, and region

Less effective identification of contacts and transmission chains

In Week 31, while the number of cases increased, the number of contacts remained stable due to a significant proportion of cases reporting no high-risk contacts. The average number of contacts per case continues to decline, particularly for contacts outside the household, reaching its lowest level observed in 2021. Although the indicator was rising for the second consecutive week, the proportion of cases previously known as contacts remains at a low level.

These results suggest that a significant proportion of at-risk contacts are not identified and/or reported by the index case. Although they are exempt from quarantine, contacts who have completed their primary vaccination series and do not have severe immunodeficiency (moderate-risk contacts) must be identified so that they can implement other measures designed to break transmission chains (testing, contact tracing, self-monitoring, limiting social interactions, wearing masks in public spaces).

• For more information, see the Week 31 report on contact tracing activities

The Delta variant is by far the most prevalent across the entire country

The L452R mutation (carried notably by the Delta variant), whose increase is stabilizing, was detected in 93.5% of positive samples screened in Week 31 (vs. 91.7% in Week 30). Sequencing data confirm that the Delta variant has been the predominant variant in mainland France since Week 26. It accounted for 98.1% of interpretable sequences in Flash Survey #17 on July 27 in mainland France (vs. 95.3% for Flash Survey #16 on July 20). In the overseas territories, screening data now indicate a predominance of Delta in Réunion, Mayotte, French Guiana, and the Antilles (sequencing data are based on too few samples).

• For more information, visit our page on Flash surveys

New estimates of vaccination coverage among healthcare professionals

On August 10, the estimated vaccination coverage in France was 67.4% for at least one dose and 56.4% for full vaccination. Among those aged 12 and older, 45,221,123 had received at least one dose (78.4%) and 37,872,330 (65.7%) were fully vaccinated. Vaccination coverage for at least one dose was 91.0% for residents in nursing homes or long-term care facilities (87.0% for full vaccination), 81.0% for healthcare professionals working in nursing homes or long-term care facilities (68.2% for full vaccination), and 89.7% for private practice professionals (84.3% for full vaccination).

Regarding vaccination coverage among healthcare professionals working in healthcare facilities, Santé publique France has published the results of the second data collection point from the follow-up study on vaccination coverage among healthcare professionals, as well as estimates derived from the Vaccin Covid baseline data. For these professionals, vaccination coverage with at least one dose was estimated at 81.3% on August 10, 2021, and at 70.1% for full vaccination. Vaccination coverage has increased over the past few weeks. Disparities in vaccination coverage are observed across different categories of professionals.

Despite the recent increase in vaccination coverage, healthcare workers in healthcare facilities remain insufficiently vaccinated, with significant disparities depending on professional category.

Targeted outreach efforts, particularly aimed at residents, students, and nursing assistants, could be implemented, especially since the latter professional category appears to be particularly at risk for COVID-19.

• For more information, see Le Point on: COVID-19 Vaccination Coverage Among Healthcare Professionals Working in Healthcare Facilities