Covid-19: JN1 variant now represents 70% of infections in France, why strain worries researchers

It is now a “number” very well anchored in the French health landscape. The JN.1 subvariant of Covid-19 – which derives from a wide range of variants belonging to the Omicron family – is now clearly in the majority in France. According to recent data from Public Health France, this new strain now represents more than 70% of virus infections in the country.

The strain – which was first discovered in France last summer – is now worrying a number of scientists. This is responsible for the surge of epidemics observed in a number of European countries in late 2023: in recent weeks, the subtype is responsible for the largest epidemic since the appearance of the Omicron variant in late 2021. / Beginning of 2022. According to many scientists, the infectivity of JN.1 makes it one of the most dangerous strains since the appearance of the delta variant in 2020.

Increases the ease of infecting our cells

Why is JN.1 of such special scientific interest to researchers? First because of its transformation. This subvariant, which is a direct descendant of the BA.2.86 variant, represents a very large number (more than 30): “It is enormous,” commented Professor Bruno Lina in our column in late summer. The only time we saw this was when we looked for the Omicron variant. At that time, scientists saw only 18″. It is these mutations that shape the characteristics of a type: aggressiveness, transmissibility, etc. “Because of the new mutations, it is possible that they are less well recognized by our immune system,” Prof. Commented Vincent Anouff, Deputy Director of the National Center for Respiratory Infections at the Pasteur Institute (CNR), together with our colleagues. Figaro.

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Since its discovery a few months ago, JN.1 has increased its ability to infect cells located in the lower part of our lungs, called “CaLu-3”. A study recently published in the journal cell Scientists at Ohio State University say that BA.2.86 and its subvariant JN.1 are able to enter these lung cells more easily than any other variant seen since 2020. While JN.1 doesn’t seem to cause serious infection cases, Shan-Liu Liu, one of the study’s lead authors, calls for caution: It’s the variety’s ability to infect our lung cells that makes it dangerous.

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“The question now is whether BA.2.86, as well as its descendants, including JN.1, will have the propensity to infect human lung epithelial cells (a protective protein tissue that lines our respiratory system to protect it, editor’s note), than the parental virus. Like the one that triggered the pandemic in 2020, Shan-Lu Liu worried in a press release. We know that the coronavirus is prone to viral recombination, which can lead to new variants with a large number of mutations that can increase immune evasion. The severity of the disease. In January 2024, the Centers for Disease Control and Prevention (CDC) reported that the JN.1 variant accounted for approximately 62% of Covid-19 cases globally: a significant increase from the previous week.