Santé Publique France says it is following this “increasing diffusion” of the Delta variant with “the greatest attention, given” its increased transmissibility and a possible increase in the severity of the infection “
The Delta variant of the coronavirus, responsible in particular for a rebound in contaminations in the United Kingdom, is still very “in the minority” in France, but in “increase” in surveillance data, Public Health France indicated on Friday.
During a “flash investigation” of sequencing carried out on May 25, this variant initially detected in India was found in 1% of samples, against 0.2% in the previous investigation, on May 11, said SPF in its report. weekly point.
The government agency said it is following this “increasing diffusion” of the Delta variant with “the greatest attention, given its increased transmissibility. […], a possible increase in the severity of the infection and preliminary data in favor of a slightly reduced vaccine efficacy, especially during an incomplete vaccination schedule ”.
For the moment, the Alpha variant (known as British) confirms its “predominance”, with 86.3% of the 1,723 samples sequenced during the “flash” survey, against 5.6% for the Beta variant (known as South African ) and 1.1% for the Gamma variant (said Brazilian). Preliminary results from the flash survey, released last Friday, indicated 88% Alpha variant and 0.5% Delta variant.
Another means of monitoring variants, the screening data of positive PCR tests no longer lists the variants as such for a few days, but three mutations “of interest”. These data show that the L452R mutation, which appears in the Delta variant, is found in 4.6% of the results.
Other variants are also carriers of this mutation, but “a large majority, probably at least two thirds are of the Delta variant”, underlined Sibylle Bernard-Stoecklin of the infectious diseases department of SPF. It is on this estimate that the Minister of Health, Olivier Véran, was based to declare Tuesday that “currently in France, 2% to 4% of the positive tests that we screen correspond to the Indian variant”.
“The impact not yet foreseeable”
These data “should be interpreted with caution due to the gradual increase in load of (the) new screening strategy put in place since May 31,” said SPF. Last week, only 37.5% of positive tests had been screened, not all laboratories being equipped with the necessary new kits yet.
In the United Kingdom, the Delta variant spread rapidly, replacing in a few weeks the Alpha variant, which appeared at the end of 2020 in the south-east of England.
Taking into account the elements showing that it has “a more important competitiveness” than the Alpha variant, “one can expect that its prevalence will increase in the weeks and the months which come” in France, judged Sibylle Bernard-Stoecklin . But “the temporality and the impact on the epidemic dynamics are not yet predictable”.