Does each new covid-19 variant pose a significant threat? — SkimNews
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- XFG (Stratus) has become the dominant covid-19 variant worldwide, accounting for around 60% of sequenced cases since first being detected in early 2025 and placed under WHO monitoring that June.
- Ian Mellis at Columbia University led lab tests showing XFG and another variant nicknamed Nimbus bind to host cells slightly less well than past variants but offset this with a greater ability to evade covid-19 antibodies.
- UK hospitals recorded 1,638 covid-19 cases in the first week of October, up from 1,328 the week before — though still lower than the same period last year, consistent with an expected seasonal rise.
- The UK Health Security Agency's Alexander Allen said there is no evidence this year's variants are making people more ill or spreading faster, noting that the autumn vaccine was specifically designed to target them.
- Leena Azhar at Fakeeh College of Medical Sciences in Jeddah reviewed XFG and characterized its evolution as "quiet," more consistent with fine-tuning than a shift toward greater virulence.
- Covid-19 sequencing data has "fallen dramatically" over the past year, according to Mellis, weakening the early-warning system that could flag a future Omicron-style jump in severity.
- Danny Altmann at Imperial College London said most children starting school have never been vaccinated against covid-19, calling government attitudes toward boosters "lackadaisical."
Why it matters: Six years into the pandemic, the dominant variant evades antibodies more effectively but existing immunity is still preventing a rise in severe outcomes — yet with sequencing data collapsing and a generation of unvaccinated children entering schools, the surveillance net that caught Omicron may not catch the next dangerous strain.
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