In France, laboratories are responsible for monitoring new variants of the virus using a very specific technique: genomic sequencing. Example at the microbiology department of the Henri-Mondor hospital in Créteil (94).

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How laboratories are tracking new variants of the coronavirus

Behind the machines and microscopes of this laboratory hides an important surveillance system. Every day, the teams receive nearly 1,000 PCR tests to analyze. The first step is to find out if the patient is infected with Covid.

If so, staff continue to investigate. Every week, he goes through nearly 200 positive samples for genomic sequencing to establish the identity card of the viruses and detect new variants.

Sequencing the genome to identify virus mutations

“The genome is a bit like a big word of 30,000 letters, explains Dr Christophe Rodriguez, virologist and director of the hospital’s genomic platform. What the sequencer will give us is the order in which they appear for each patient. ”

It is from this succession of letters that Dr Slim Fourati, virologist, can detect the different variants. “From one patient to another, we will have certain sequence changes at very specific positions which will allow us to identify certain mutations which are specific to one variant or another. ”

Vital information for health authorities

If new, more contagious variants are detected, the authorities may decide to strengthen health measures and adapt the vaccination strategy. The laboratory also checks that diagnostic tests continue to detect all variants. It can finally update new mutations.