By late summer 2025, a new SARS-CoV-2 variant, informally dubbed “Stratus” or “Frankenstein” due to its hybrid nature, became dominant across Europe, leading to a noticeable surge in infections. While health authorities maintain the variant currently has a limited impact on hospitalisations, experts are cautioning the public to be aware of specific, sometimes mild, symptoms associated with this new strain.
Public Health France reported a significant rebound in suspected COVID-19 infections in mid-September, with a 37% increase in adult emergency room visits between September 15th and 21st, 2025. This rise coincides with the widespread circulation of the variant, scientifically designated “XFG,” which has been under the scrutiny of European health authorities since July. Despite its prevalence, the European Centre for Disease Prevention and Control (ECDC) has stated that its impact on hospital admissions remains “limited.”
However, health professionals are highlighting a trend of subtle symptoms linked to the Stratus variant. In the UK, where the XFG variant is also widespread, some specialists have observed clinical manifestations that might appear innocuous. Dr. Alex Allen, a consultant epidemiologist with the UK Health Security Agency, told The Independent that while there’s no current evidence to suggest the variant causes more severe illness or reduces vaccine efficacy, patients are reporting “atypical symptoms, like a hoarse voice,” similar to the “razor-blade sore throat” experienced with the earlier “Nimbus” strain.
Adding to this, Dr. Gareth Nye from the University of Salford commented in the Mirror that while Stratus is “almost identical to other variants” in many respects, those infected tend to experience “a very sore throat and a hoarse voice, unlike the more general symptoms like a cough, fever, or body aches.”
In France, Dr. Guillaume Braconnier, a general practitioner in Lille, has also noted an increase in “flu-like syndromes” that are difficult to definitively attribute to COVID-19, partly due to a reduction in testing compared to earlier in the pandemic. He explained to France 3 Hauts-de-France that many of these syndromes could indeed correspond to the new variant.
Amidst the increase in cases, France’s national health insurance has announced that its latest SARS-CoV-2 vaccination campaign will commence on October 14th. It is strongly recommended that individuals at higher risk of developing severe COVID-19 be vaccinated to ensure immunity. This includes people over 65 years old and those with pre-existing health conditions.
Furthermore, an additional vaccine dose is strongly advised for the most vulnerable populations in the spring. This recommendation specifically targets individuals aged 80 and above, immunocompromised patients of all ages, residents of nursing homes, and anyone deemed at very high risk following an individual medical assessment.
