Overview

• Stratus and its offshoot XFG.3 have surged from 10% of Covid cases in England in May to around 40% by mid-June
• The World Health Organization designated Stratus as a 'variant under monitoring' on June 25 after its global share reached roughly 22%
• Researchers link the variant’s rapid spread to spike protein mutations that enhance immune escape and fuel transmissibility
• Current data show no evidence of increased severity or hospitalizations associated with Stratus and vaccines remain effective against severe disease
• Experts warn that waning immunity and low booster uptake could leave populations vulnerable to a fresh wave, underscoring the need for continued surveillance and vaccination efforts