The UK Health Security Agency has revealed that the new Covid variant known as “Stratus” has become the dominant strain across the United Kingdom. This variant, officially designated as XFG, has been described by experts as a “Frankenstein” strain due to its unique genetic makeup. The World Health Organisation has also issued a statement predicting that Stratus will soon become the leading variant globally, with symptoms that differ from the traditional Covid indicators such as a heavy cough and fatigue.
Dr. Kaywaan Khan, a Harley Street GP and founder of the Hannah London Clinic, explained to Cosmopolitan UK that Stratus possesses specific mutations in the spike protein. These mutations could potentially help the virus evade antibodies generated from previous infections or vaccinations. However, Dr. Khan emphasized that Stratus does not appear to cause more severe illness, hospitalizations, or deaths compared to earlier Omicron variants. He noted a distinctive symptom of this variant: “One of the most noticeable symptoms of the Stratus variant is hoarseness, which includes a scratchy or raspy voice.”
The Rise of the Stratus Variant
The Stratus variant, or XFG, has rapidly increased its prevalence, accounting for nearly 40% of Covid cases in England by mid-June, up from 10% in May. As a descendant of the highly transmissible Omicron variant, Stratus is classified as a “recombinant” or “Frankenstein” strain. This classification means it emerged when an individual was simultaneously infected with two Covid strains, resulting in a new hybrid variant.
Professor Lawrence Young, a virologist at Warwick University, highlighted the rapid spread of Stratus and its sub-lineage XFG.3. “The increased competitiveness of XFG and XFG.3 is likely due to new spike mutations which make these variants more able to evade the immune response,” he said. With waning immunity in the population due to a decline in booster uptake and a reduction in recent Covid infections, more individuals are susceptible to these new variants.
Understanding “Frankenstein” Variants
The term “Frankenstein variant” is used to describe strains like Omicron and its descendants, including XFG (“Stratus”) and hybrids such as “Deltacron.” These variants are characterized by numerous mutations, particularly in the spike protein, which is crucial for the virus’s entry into cells. Some variants, like Deltacron, are literal hybrids formed through the recombination of different strains within a single infected person.
Early data from the UK suggests that highly mutated variants, such as BA.2.86, exhibit similar levels of antibody escape compared to other circulating variants, with no evidence indicating they cause more severe illness. Dr. Michael Gregory, regional medical director for NHS England in the North West, noted the rapid spread of these variants in communities, with primary symptoms including a “razor blade” sore throat and swollen neck glands.
Common Symptoms and Public Health Implications
The symptoms associated with newer Covid variants, including “Frankenstein” variants, generally mirror those of previous Omicron subvariants. Common symptoms include upper respiratory issues such as fever, cough, sore throat, runny nose, and sneezing. Other frequently reported symptoms are fatigue, headache, muscle aches, and loss of appetite. While the loss of smell or taste was a more indicative symptom in earlier strains, it appears less common in Omicron infections.
Professor Young warned that, given the current state of immunity in the population, a new wave of infections could occur, although the extent is difficult to predict. He reassured that there is no evidence to suggest Stratus causes more severe illness, and vaccination remains a crucial defense against severe outcomes.
As the Stratus variant continues to spread, public health officials emphasize the importance of vaccination and booster shots to maintain immunity and protect against severe disease. The situation underscores the need for ongoing surveillance and research to adapt to the ever-evolving landscape of Covid-19 variants.