In the final months of 2025, new Covid-19 variants are once again making headlines across the UK and the US. While they are not believed to be more dangerous than earlier strains, their rapid spread and unusual symptoms are drawing attention from both the public and health authorities. Dubbed Stratus (XFB) and Nimbus (NB.1.8.1), these two variants are fueling a sharp rise in infections at the very moment health systems are bracing for the pressures of winter.
Reports from doctors and patients highlight a particularly striking symptom: an intensely painful sore throat described as feeling like “razor blades.” For many, this has become a tell-tale sign of infection, alongside the more familiar cough, fatigue, and runny nose.
A Surge in Cases
The spread of Nimbus and Stratus is significant. In the UK, the Health Security Agency (UKHSA) has confirmed that positivity rates have jumped from 7.6% to 8.4% in just one week. Hospital admissions have also crept up, rising from 2.0 to 2.73 per 100,000 people. Though these numbers might appear modest compared to the peaks of previous waves, the upward trend is clear, and health leaders are warning of the added strain during winter when flu and other respiratory infections are already common.
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