At the end of February, the public health agency (
ARS) was informed by the Lannion hospital of a "worrying cluster" where 71 people tested positive to
Covid-19 (44 patients and 27 workers).
Three weeks later, on 13 March, the number was revised to 79 positive cases, eight of them found to be carrying the so-called "20-C" variant, the scientific name given to the mutation.
"What we found strange was that some of these infected people had done up to four negative tests," said one hospital source.
Scientists are now trying to establish if the mutations in the Brittany variant are such that the virus become undetectable to nasal PCR testing. If that turns out to be the case, then the number of those infected could be much higher.