Indicators remain at high levels

In week 52, the number of confirmed cases was 82,457. Testing rates have been rising since Week 50 (December 7–13, 2020) (+14% between W49 and W50, +75% between W50 and W51, +26% between W51 and W52) and have increased significantly in recent weeks due to the holiday season. Therefore, analysis of trends in the number of confirmed cases and positivity rates must remain cautious, as these indicators are strongly influenced by fluctuations in testing rates and do not solely reflect the actual progression of the epidemic.

During week 52, the number of tests continued to rise, and an average of 11,780 confirmed cases were reported daily in France. Over the first four days of the week, the average number of cases was 17,348 per day, and 4,356 over the last three days.

The number of new COVID-19-related deaths, including deaths occurring in hospitals and long-term care facilities, decreased in week 51 compared to the previous week (2,421 deaths in W51 vs. 2,878 in W50, -16%). However, the holiday period may contribute to a delay in data consolidation.

Nearly 8% of the population is estimated to have been in contact with SARS-CoV-2 in early October

The epidemiological update presents the estimated prevalence of SARS-CoV-2 infections in France for Week 41 (October 5–11, 2020), prior to the nationwide curfew and the second national lockdown. The proportion of people seropositive for SARS-CoV-2 in week 41 is estimated at 7.9%, or 5,256,000 seropositive individuals.

Three previous surveys conducted in weeks 11 (March 9–15), 15 (April 6–12), and 20 (May 11–17) had revealed an increase in national seroprevalence from 0.3% to 4.9% during the first wave of the epidemic.

Since the end of the first wave in week 20, seroprevalence has increased across all age groups. Those aged 50–59 remained the most affected (9.3%) in week 41. Among children under 10, seroprevalence increased to a lesser extent, reaching 5.7%. Due to a possible decline in antibodies over time and an immune response that is too weak to be detected in cases of asymptomatic infection, it is possible that these seroprevalence estimates are slightly lower than the actual prevalence of SARS-CoV-2 infections in the French population. These prevalence levels confirm that a large portion of the population had not yet been exposed to SARS-CoV-2 prior to the second wave of the pandemic in late 2020.