A newly identified COVID-19 variant, known as **Stratus**, is rapidly spreading across the globe, characterized by a unique early symptom that differentiates it from other strains. First detected by health officials in **January 2025**, the variant has two subtypes, XFG and XFG. As of **June 2025**, the **World Health Organization (WHO)** added the XFG subtype to its monitoring list due to its accelerated transmission rates.
Typically, COVID-19 symptoms resemble those of other respiratory illnesses, such as fever, cough, and runny nose. However, Stratus presents an unusual early sign: a hoarse or raspy voice. This symptom may occur before more common indicators of infection, which can lead to it being overlooked. Alongside this, medical professionals have noted other symptoms such as sore throats, nasal congestion, digestive issues, and extreme fatigue.
The variant gained significant traction in the United States during the summer of **2025**, quickly becoming the dominant strain. According to health authorities, a summer surge was attributed to Stratus and another variant called “Nimbus.”
Dr. **Gareth Nye** from the **University of Salford** explained, “In most ways, it’s almost identical. However, people with this version tend to get very sore throats and a hoarse voice, compared with the other more general symptoms like cough, temperature, and aches.” He further emphasized that spikes in illnesses often coincide with children returning to school, where close contact and lower hygiene standards can exacerbate transmission.
Emerging evidence suggests that the Stratus variant can partially evade the immune system. This factor raises concerns regarding the efficacy of previous COVID-19 vaccines. Therefore, health officials urge individuals to stay current with their vaccination schedules.
Having first appeared in **Southeast Asia**, Stratus quickly spread to the U.S. by **March 2025**, with a notable increase in cases by May and June. By **mid-September 2025**, it was identified as the dominant variant in U.S. wastewater. Estimates indicated that by the end of September, Stratus accounted for approximately **85%** of COVID-19 cases in the country.
Despite these developments, the **WHO** has reassured the public that currently approved COVID-19 vaccines are expected to remain effective against severe illness caused by this variant. Dr. **Peter Chin-Hong**, affiliated with the **University of California, San Francisco**, cautioned that Stratus displays a broader range of symptoms than previous strains. “There’s a little bit more sore throats with some people, particularly older adults who didn’t get vaccinated last year,” he noted.
As children return to school, Dr. Chin-Hong pointed out that even mild symptoms like a sniffle could indicate a COVID-19 infection, increasing the likelihood of widespread transmission.
While the emergence of a new variant can naturally cause concern, **GOV.UK** emphasizes that virus mutation is a normal occurrence. The organization is actively collecting data to better understand how to combat these changes. “It’s normal for viruses to mutate and change, and as more data becomes available on these variants, we’ll have a better understanding of how they interact with our immune systems,” the public health authority stated.
The key takeaway remains the importance of vaccination, particularly for those eligible. As health officials continue to monitor the situation, keeping up with vaccinations will play a crucial role in mitigating the impact of the Stratus variant and protecting vulnerable populations.
