Variants of Covid-19 are increasingly present in France, especially in the Paris region.

“It was rather around 6% on January 7th and we climbed to 15-20% last week. It’s exponential growth“, indicated Rémi Salomon, president of the medical commission of the Public Assistance-Hospitals of Paris, Tuesday February 2 on Franceinfo.

Identify variant mutations

To better identify the British, South African and Brazilian variants, a laboratory has developed a rapid technique known as screening PCR. This involves identifying mutations characteristic of the variant on positive tests for Covid-19.

” Screening is nothing more or less than the same amplification reaction that is used for screening. The difference will lie in the fact that we are not looking for sequences that are common to the coronavirus, we are going to specifically look for areas of the genome which are areas that carry mutations and it is these mutations that we will amplify in a very specific », Explains François Cornu, president of the Eurofins Biomnis laboratory.

Detection within hours

Thanks to this screening technique, the detection of the British variant is done in a few hours. An essential speed to analyze the progression of the variant on the territory. Until very recently, only a much longer method, sequencing, was used to look for variations in the virus.

” The all-inclusive analytical process from the arrival of the sample to the rendering of results will take an average of nine hours, while sequencing is a different tool, there we are not looking for specific areas, we read the The whole genetic message of the virus, we establish our identity card, and this identity card is longer to produce since it takes on average between 5 and 7 days to proceed with the sequencing », Explains François Cornu, president of the Eurofins Biomnis laboratory.

Two complementary methods

While the development of this new technique is good news, this does not mean that the sequencing of the virus should be stopped. The two methods are complementary to analyze the progression of known mutations and to detect possible new variants.

” The problem is that the variants do not stop evolving and that this will require that the PCRs adapt permanently and it is not very easy to adapt the PCRs. Sequencing absolutely does not require having prior knowledge of mutations, and therefore if new ones emerge, then we can find them. », Explains Dr Christophe Rodriguez, virologist.

Knowing the identity card of the variants could make it possible to adapt the vaccines to these mutations. A global database has been created to pool all knowledge on the subject.