By Sudouest.fr with AFP
Increased sequencing, improved tracing, more coercive isolation: is France now equipped to “track the virus”, as the government promises, and avoid a fourth wave of Covid-19 due to the Delta variant?
It is the most effective bulwark, but “the vaccine strategy alone is not enough” to avoid “waves or a too important rebound”, warns the epidemiologist Antoine Flahault, director of the Institute of global health at the university from Geneva.
Collective immunity at 85%
With a Delta variant considered to be 40% to 80% more contagious than the Alpha, “the level of requirement for minimum vaccination coverage is higher than what was initially thought”. It would take “85% of people immunized for the epidemic to stop”, assesses Pascal Crépey, researcher in biostatistics at EHESP.
For now, only a third of the population is fully vaccinated in France and the government expects 35 million people at the end of August, or 52%.
It is therefore necessary “to couple vaccination with a strategy of minimal circulation of the very offensive virus”, pleads Professor Flahault. The good news is that France is “better equipped” than last summer to prevent the fall wave scenario from repeating itself.
Relaunch screening
The ebb of the epidemic is restoring the effectiveness of conventional measures (screening, tracing, isolation), which are overwhelmed when tens of thousands of new cases are detected every day.
Last week, the country even fell below 2,000 new daily cases on average. “It is no longer the virus that stalks us, it is we who stalk it”, recently assured the Minister of Health, Olivier Véran, in the Journal du dimanche
Olivier Véran has promised free self-tests this summer, with 7.5 million kits distributed on the vacation route, resorts, in leisure centers and among precarious audiences. And at the start of the school year, the challenge will be “massive screening at school level, because we know that it is in this unvaccinated population” that the virus will run, “said the president of the Scientific Council Jean- François Delfraissy on France Inter.
Identify variants
Virus sequencing makes it possible to identify variants and to know how they circulate. Since its launch at the end of January, 79,011 positive samples have been sequenced, against around 2,000 sequences in 2020. However, we are still far from the objective of 10,000 sequences per week for an announced time.
Private laboratories will be associated with this effort and should soon make it possible to “double the capacities of the four public platforms”, according to Public Health France. But the name of the selected laboratories will not be known until “around July 27”.
Since the emergence of the Beta, Gamma and Delta variants, the authorities have tightened the conditions of isolation, gradually implementing a mandatory quarantine for travelers from countries at risk. Asked about the advisability of drastically restricting flights with the countries concerned, Professor Delfraissy felt that it was “already too late” to hope to prevent the progression of the Delta variant in this way.
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