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Effects of #LP81 - adapted #mRNA #vaccination on #SARS-CoV-2 variant #neutralisation

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By G.M.

 


{Summary}

SARS-CoV-2 continues to evolve, with successive variants evading immunity established by previous infection or vaccination. In mid-2024, a vaccine tailored to the JN.1 variant was authorised by the European Medicines Agency (EMA), which boosted neutralising antibody responses and provided substantial protection against severe disease and hospitalisation.1–3 Around 6 months later, in January 2025, LP.8.1 (of the JN.1 lineage) was classified as a “variant under monitoring” by WHO, due to its epidemiological importance and enhanced transmission fitness relative to contemporaneous strains. After emerging in late 2024, LP.8.1 rapidly overtook the XEC variant, establishing dominance throughout the Americas and Europe by early 2025. In the USA, LP.8.1 and its sublineages represented more than 50% of all sequences in May, 2025 (appendix p 9). Although vaccines adapted to JN.1 or its derivative KP.2 generated neutralising antibodies against LP.8.1, these titres were reduced compared with earlier JN.1 lineage variants, indicating continued antigenic drift.4 By mid-2025, the XFG lineage emerged and began replacing LP.8.1 across multiple geographical regions (appendix p 9), indicating further adaptive evolution within the JN.1-derived clade. Subsequent investigations confirmed robust immune evasion coupled with diminished angiotensin-converting enzyme 2 (ACE2) receptor binding efficiency for the XFG variant.4

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