Prime Highlights:
- The XFG or “Stratus” strain is spreading very fast globally with a telling symptom of hoarseness.
- Despite being very infectious, it causes light illness and is very closely monitored by global health agencies.
Key Facts:
- XFG is a recombinant strain built from two Omicron sublineages, LF.7 and LP.8.1.2.
- Over 38 nations have reported instances and represented 24% of world genomic sequences in the recent past.
Key Background
Variant of Stratus COVID-19, also referred to as XFG, has emerged as a recombinant between Omicron subvariants. It was initially reported in Canada in early 2024 and has subsequently been reported in over three dozen nations. It has spread most significantly in Europe, including Ireland and the UK, where it now accounts for 30–40% of all new cases of COVID-19 in some regions. XFG is recognized by the World Health Organization (WHO) as a Variant Under Monitoring due to its higher number.
Although XFG presents all the usual symptoms of Omicron like fever, sore throat, fatigue, aches, and mild respiratory symptoms, the physicians are observing one unusual and repeated symptom: hoarseness or a harsh voice. Such a vocal symptom is reported to be more typical of XFG infections than of any others. Medical authorities advise self-isolation for patients presenting such symptoms for at least 48 hours after recovery in an effort to terminate transmission.
Genomic sequencing indicates that XFG has multiple spike protein mutations making it more transmissible and immune system evasive. These include such mutations as His445Arg and Gln493Glu, which are responsible for its partially evading prior immunity by infection or vaccination. However, even with this, the variant somehow continues to cause extremely mild disease in the majority of the population that it infects, and no reported surge in hospitalization and deaths ascribed directly to it.
Public health experts warn that reduced immunity and less booster dose could help the XFG variant spread more widely. But present vaccines will still guard against severe illness and disease. Ongoing vigilance in surveillance, genomic surveillance, and public health remains ongoing, supplemented by the possibility of earlier detection with the hoarseness symptom.
