Experts Warn: Highly Infectious "Stratus" Now Dominant COVID Strain

A new COVID-19 variant, unofficially named "Stratus" and scientifically known as XFG, is now the most prevalent strain in England, raising concerns among experts about a potential surge in new infections. Scientists believe Stratus is more contagious than previous COVID strains due to mutations that allow it to better evade the immune system.

According to data from the UK Health Security Agency (UKHSA), Stratus accounted for approximately 10% of all COVID cases in May but rapidly escalated to about 40% by mid-June, just three weeks later.

Understanding the "Frankenstein" Variant

Stratus is classified as a "recombinant" or "Frankenstein" strain, meaning it's a descendant of the highly virulent Omicron variant. This designation indicates that Stratus emerged as a new hybrid when an individual was simultaneously infected with two different COVID strains.

Professor Lawrence Young, a virologist at Warwick University, told MailOnline that the original XFG strain and its offshoot, XFG.3, are both "rapidly spreading." He attributes their increased competitiveness to "new spike mutations which make these variants more able to evade the immune response.

Professor Young also noted a concerning trend: "Given that immunity to Covid is waning in the population due to a decline in uptake of the spring booster jab and the reduction of Covid infections in recent months, more people will be susceptible to infection with XFG and XFG.3." He cautioned that this could lead to a new wave of infection, though its extent remains difficult to predict.

Despite its increased transmissibility, there is currently no evidence that Stratus causes more severe illness. Professor Young emphasized that receiving the COVID vaccine is "very likely" to provide protection against hospitalization and severe sickness.

Global Monitoring and Other Variants

The World Health Organization (WHO) designated the Stratus strain as a "variant under monitoring" shortly before its rapid rise in the UK. Health agencies worldwide have been urged to assist in tracking it due to its increasing global spread and potential public health implications. While the WHO classified the overall risk of Stratus as "low," it acknowledged the variant's notable growth advantage over other strains, accounting for 22% of global infections.

In recent weeks, another novel COVID variant named Nimbus has also seen a significant increase. UKHSA data shows Nimbus jumped from just 2% of cases in April to 17% in June.

Despite the emergence of these new variants, the overall number of COVID cases has been declining in recent weeks. For the week ending June 29, only 5.4% of COVID tests analyzed by UKHSA returned positive results. This is a slight decrease from the 7% positivity rate in the preceding week, which was the highest recorded this year.

Neither Nimbus nor Stratus are believed to cause novel symptoms compared to earlier strains. However, medical professionals have cautioned that Nimbus might present with a "razor blade" sore throat. Dr. Michael Gregory, Regional Medical Director for NHS England in the North West, recently noted, "The variant looks to be spreading rapidly within communities, with top symptoms being a 'razor blade' sore throat and swollen neck glands.”

It remains crucial to remember that any COVID infection can still be fatal, particularly for vulnerable populations such as the elderly or individuals with weakened immune systems.

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