The Stratus Variant (XFG): Symptoms, Global Spread, and Impact in Late 2025

The Stratus variant, scientifically designated as XFG, is a sublineage of the Omicron family of SARS-CoV-2 (the virus causing COVID-19). It was first detected in Southeast Asia in January 2025 and classified by the World Health Organization (WHO) as a Variant Under Monitoring (VUM) on June 25, 2025. XFG is characterized by specific genetic mutations, including JF1 + S:T22N, S:S31P, S:R190S, S:R346T, S:K444R, S:V445R, S:F456L, S:N487D, S:Q493E, and S:T572I, which contribute to its increased transmissibility compared to some prior Omicron subvariants. It has a estimated daily growth advantage of about 6% over other circulating strains. The WHO's initial risk evaluation considers it a low public health risk overall, with no clear evidence of increased severity or immune evasion beyond existing Omicron variants.

Symptoms

Symptoms of the Stratus (XFG) variant are largely consistent with those of previous Omicron subvariants, though anecdotal reports and social media discussions highlight a few potentially distinctive features, such as a more intense sore throat or hoarseness. There is no confirmed evidence that XFG causes more severe illness or novel symptoms compared to earlier strains. The incubation period appears similar, typically 2-5 days. Here's a breakdown of commonly reported symptoms based on health authority data and expert analyses:

Symptom Category: Respiratory

• Specific Symptoms: Sore throat (often severe, described as "razor blade" sensation), Cough, Shortness of breath or difficulty breathing, Congestion or runny nose, Hoarseness (scratchy or raspy voice)
• Notes: Hoarseness and severe sore throat are more frequently mentioned with XFG than some prior variants.

Symptom Category: General/Systemic

• Specific Symptoms: Fever or chills, Fatigue, Headache, Muscle or body aches
• Notes: These are the most common early signs, similar to flu-like illness.

Symptom Category: Other

• Specific Symptoms: New loss of taste or smell, Nausea or vomiting, Diarrhea, Chest pain, Trouble staying awake 
• Notes: Less common; chest pain and sleep issues have been linked in some U.S. reports, but not widely confirmed.

Health experts emphasize that symptoms can vary by individual factors like age, vaccination status, and prior infections. Testing remains key for confirmation, as symptoms overlap with other respiratory illnesses.

Global Spread

XFG has spread rapidly since its emergence, leveraging mutations that enhance its transmissibility. By late June 2025, it accounted for approximately 22.7% of globally sequenced COVID-19 cases, up from near-zero earlier in the year, and had been detected in at least 38 countries. Its growth has been particularly notable in the U.S., where it became one of the dominant strains by mid-2025, comprising about 14% of cases nationally by late June and surging to higher proportions in regions like the West and South. In Europe, including the UK, it rose from 1% to nearly 30% of infections in a six-week period ending in June. Other areas, such as California and New York, reported localized dominance by August 2025.

Competing with variants like Nimbus (NB.1.8.1), XFG has driven waves in multiple regions, with wastewater surveillance indicating moderate to high activity. Global monitoring suggests it could continue spreading into fall, potentially being displaced by emerging strains like XEC.

Impact in Late 2025

As of August 31, 2025, XFG is fueling a late-summer surge in cases across the U.S. and parts of Europe, with the CDC upgrading wastewater COVID-19 activity from "low" to "moderate" in early August. Hospitalizations have risen in states like California, but remain lower than peaks in prior years, and deaths are not significantly elevated. In the Bay Area and New York, it has become the predominant strain, contributing to increased emergency visits but not overwhelming healthcare systems.

Looking toward late 2025 (fall and winter), projections are limited due to the evolving nature of variants, but experts anticipate XFG could sustain or amplify seasonal waves if not outcompeted by newer strains. Its growth advantage raises concerns for higher transmission during colder months, potentially straining resources in under-vaccinated areas. Updated vaccines targeting related strains (e.g., XEC formulations) are rolling out in fall 2025, expected to offer cross-protection against XFG, though effectiveness details are pending real-world data. Globally, impacts include delayed vaccine approvals and localized outbreaks, but overall severity remains low, with no evidence of heightened virulence. Public health measures like masking and ventilation continue to be recommended to mitigate spread.

 

Prevention for the Stratus Variant (XFG)

• Preventive Measures: Standard COVID-19 precautions remain effective: mask-wearing in crowded or high-risk settings, nasal and hand hygiene, mouth gargle, and avoiding close contact with symptomatic individuals.
• Testing and Isolation: Test promptly if symptoms appear, and isolate if positive to prevent spread. Avoid large gatherings, especially in areas with high transmission. 

• Most mainstream doctors (e.g. here) still recommend acetaminophen (paracetamol), despite strong evidence indicating it is associated with a 24% [9–40%] higher mortality risk in COVID-19 patients. A pooled analysis focusing on the most severe outcomes shows an even higher risk—28% [17–41%] increased mortality (1, 5). Given this evidence, patients and healthcare providers should carefully weigh the risks and benefits of acetaminophen for COVID-19 symptom management and consider alternative approaches when appropriate.

• Concerns about acetaminophen’s use in COVID-19 stem from multiple potential mechanisms of harm, including glutathione depletion, fever suppression, liver toxicity, immunosuppression, cytokine disruption, prostaglandin and COX inhibition, mitochondrial dysfunction, oxidative stress, and microbiome alteration. Fever, a natural defense against infection, is suppressed by acetaminophen, potentially prolonging illness and impairing immune responses (1, 6, 7, 8).
• Dr. Peter McCullough recommends staying proactive. "Nasal sprays and gargles are the best prevention measure,” says Dr. McCullough, emphasizing simple, frontline strategies to reduce viral load and help stop infection before it starts.

The WHO classifies XFG as a low public health risk, with no evidence of reduced vaccine effectiveness beyond existing Omicron variants, but ongoing monitoring is advised.

Related: Efficacy and Advantages of Nasopharyngeal and Oropharyngeal Treatments for Early Intervention and Prophylaxis in Respiratory Viral Infections: A Systematic Review and Meta-Analysis (2025)

Treatment for the Stratus Variant (XFG)

Treatment for XFG infections does not differ significantly from other COVID-19 variants, as there is no evidence of increased severity. Focus is on symptom management, early intervention for high-risk individuals, and monitoring for complications. Consult a healthcare provider for personalized advice.

• Symptom Relief: For those experiencing the unique sore throat, recommended relief measures include staying hydrated, using throat lozenges and mouth gargles, and employing humidifiers. 
• As for when you should go to an urgent care or emergency room? When you have chest pain, have a hard time waking up or staying awake, or feel confused and disoriented, the CDC advises. “If you have COVID or COVID-like illness and have worsening trouble breathing or chest pain, you should be evaluated at your doctor’s office, urgent care or the ER,” Dr. Zachary Hoy (a pediatric infectious disease specialist with Pediatrix Medical Group in Nashville, Tennessee) said.
• Hospital Care: In cases of severe illness, hospitalization may involve oxygen therapy, steroids, or other supportive treatments, but this is uncommon with XFG due to its similarity to prior mild Omicron strains.

Health experts note that early testing and treatment can significantly reduce the risk of progression to severe disease.

How effective are the vaccines against XFG?

It’s too early to know exactly how effective and safe the shots are — as the research on XFG variant is limited since it’s new. Discuss with your trusted medical provider with regard to the potential benefits and risks.

Conclusion

Early treatment is critical and the most important factor in managing this disease. COVID-19 is a clinical diagnosis and treatment should be initiated immediately after the onset of flu-like symptoms. 

At present, the Independent Medical Alliance (previously FLCCC) seems to have one of the best treatment protocols for COVID treatment. It’s called I-CARE protocol. The multiple therapies and drugs in the I-CARE protocol have different mechanisms of action and work synergistically during various phases of the disease.

Action Steps for the Public:

• Stay informed through reputable health sources.
• Continue practicing standard COVID-19 precautions, especially in high-risk settings.
• Seek medical advice if experiencing persistent or severe symptoms.