JN.1 will very quickly become the dominant Covid variant worldwide. It is the prediction made by a team of scientists on the basis of identity card of this rapidly rising Sars-CoV-2 mutant. In a study published in 'The Lancet Infectious Disease', researchers from the Department of Microbiology and Immunology, Institute of Medical Science at the University of Tokyo, demonstrate that this is “one of the most immune-evading variants to date” .
The identikit of the JN.1 variant
'Daughter' of the highly mutated variant dubbed Pirola by experts on social media (BA.2.86), JN.1 emerged at the end of 2023 and for some scientists it could represent a turning point for the virus on the same scale as Omicron. So much so that these experts say the time has come for the World Health Organization (WHO) to assign a new Greek letter.
In the study, Japanese scientists reconstruct its characteristics starting from mother Pirola. The BA.2.86 lineage, identified for the first time in August 2023, ended up practically immediately under the spotlight of science: it was in fact found to be phylogenetically distinct from the circulating XBB variants (on which the updated vaccines currently in use in the countryside are also based vaccines), including Eris (EG.5.1) and HK.3, which last November was already one of the XBB lineages with the highest growth advantage.
Pirola already carried more than 30 mutations in the Spike protein, indicating a high potential for immune evasion. Its descendant JN.1 (BA.2.86.1.1) harbors a further mutation that has turned on a 'red flag' for scientists: it is called Leu455Ser (to which JN.1 adds 3 other mutations in non-spike proteins). Why should you worry? Leu455Ser is a characteristic mutation of JN.1, but other variants carried a similar mutation, such as HK.3 and some so-called 'Flip' variants, which contributed to increasing their transmissibility and immune escape capacity.
Scientists delved into the characteristics of JN.1, estimating its reproductive number (which indicates transmissibility) based on genomic surveillance data from France, the United Kingdom and Spain. In all three countries the reproductive number of JN.1 was higher than that of the latest version of Pirola (BA.2.86.1) and HK.3. Not surprisingly, at the end of November 2023, JN.1 had already surpassed HK.3 in France and Spain. The other tests conducted by the researchers confirmed these characteristics and highlighted a “solid resistance” of JN.1 (compared to Pirola) to sera from people vaccinated with the monovalent anti-XBB.1.5 vaccine. “Taken together, these results suggest that JN.1 is one of the variants that most evade the immune system – conclude the authors -. And what emerged also suggests that the Leu455Ser mutation contributes to increasing immune evasion, which partly explains the 'increase in the reproductive number of JN.1”.
#Covid #JN.1 #variant #behaves #identikit
