Infection rates have risen in France, but despite worrying figures in some departments, in most areas there are only a fraction of cases. 

Last week, the French government published the latest results of Covid-19 testing activity for the week ending 2nd August.

During the week 526,000 individuals were tested, of whom 7,565 tested positive, an increase of 33% in the number testing positive on the previous week. This was greater than the increase in the number of patients tested, which increased by 14% .

Just over half of those who tested positive were asymptomatic. Among the asymptomatic cases, more than half (54%) were between 15 and 44 years of age.

The rate of infection was also on the rise, with 11.6 cases/100,000 inhabitants, against 8.7 cases/100,000 inhabitants the previous week; the same trend was observed for the percentage testing positive; 1.5% against 1.3% the previous week, an increase of 15%.

Twenty-one departments in mainland France had infections rates above 10/100,000 inhabitants in the week, including 10 above 20/100,000 inhabitants (only the two departments of Val d'Oise and Mayenne the previous week). A rate above 10 is a 'vigilance' threshold, whilst above 50 it triggers an 'alert'. In both cases, an in-depth risk analysis is launched in order to identify the causes and measures that may be necessary.

The highest infection rate was observed in Mayenne (48/100,000), making it the only department in mainland France that has been classified as having a high level of vulnerability, as shown below.

The departments outside of the Ile-de-France considered to have moderate rate of vulnerability were:

• Haute-Savoie (27/100,000)
  
• Bouches-du-Rhône (24/100,000)
  
• Nord (23/100,000)
  
• Sarthe (18/100,000)
  
• Ille-et-Vilaine (18/100,000)
  
• Alpes-Maritimes (17/100,000)
  
• Meurthe-et-Moselle (17/100,000)
  
• Haute-Garonne (16/100,000)
• Loire (12/100,000)
  
• Loiret (12/100,000)
  
• Gard (11/100,000)
• Ain (11/100,000).

In Mayenne, the number of confirmed cases decreased sharply in the week (149 against 454 in the previous week), equivalent to an infection rate of 47.8 cases per 100,000 inhabitants, a major decrease compared to the previous week (148.7/100,000). The percentage tested positive in the department also follows the same trend, with a decrease to 1.4% against 3.5% in the previous week.

In Sarthe, a department bordering Mayenne, a sharp increase in the infection rate was observed, with 17.9 cases per 100,000 inhabitants against 10.4/100,000 in the previous week. The percentage testing positive followed the same trend, with 3% in the week against 2% in the previous week.

In the Ile-de-France, the infection rate rose sharply (15.3/100,000 to 23.8/100,000), and up significantly in 4 departments - Paris (17,5/100,000 inhabitants to 30,5/100 000), Seine-Saint-Denis (16.7/100 000 to 28.3/100,000), Hauts-de-Seine (15,9/100 000 to 22.9/100 000) and Val-de-Marne (15.2/100 000 to 28.1/100 000).

As a result of the increase in infection rates, the mandatory wearing of masks in busy public areas has become more widespread in France, alongside the existing legal obligation to wear a mask in enclosed areas. There is mixed compliance with both precepts.

Scientists in France advising the government have warned of the 'high probability' of a second wave of the virus in the autumn or winter.

The following table provides a summary of testing activity in each department, with the main results of that testing. Although the numbers tested in each department vary substantially, account must be taken of the population density in each department. Nationally the screening rate increased in the week, from 779/100,000 inhabitants against 685/100,000 for the previous week.

As can be seen, the picture is a very varied one. More fine grained analysis would show even these figures underestimate the geographic variations, particularly between rural and urban areas within a department.