Stratus Variant Spreads Across US and UK

An Omicron-derived “Stratus” lineage (XFG and subvariants such as XFG.3), first detected in January 2025, has rapidly spread beyond the UK and is now estimated to account for a large share of infections in both the U.S. and the UK. U.S. CDC Nowcast data and wastewater surveillance show rising XFG levels — wastewater is moderate nationally but many states report high or very high viral loads — and health authorities have reported case spikes and rising hospital admissions in some regions. Clinicians say Stratus (with co-circulating NB.1.8.1/Nimbus) often causes a distinctive hoarse or raspy voice and very sore, “razor‑blade” throats alongside typical symptoms such as headache, cough, nasal symptoms and fatigue, with some patients reporting severe fatigue and jaw or tooth pain. WHO and early assessments indicate XFG appears slightly more transmissible and can evade some immunity but so far has not been shown to cause more severe disease, and existing vaccines are still expected to reduce symptomatic and severe illness. Public‑health agencies are urging eligible people to take updated COVID, flu and RSV vaccines, maintain hygiene and isolate when symptomatic as flu and RSV also rise; some advisory bodies have moved away from blanket universal booster recommendations, and hospitals — including pediatric and private facilities — are reporting increased admissions for viral respiratory illness.