New Covid UK 'Stratus strain is 'Frankenstein' type say experts as symptom emerges

The new highly contagious strain of Covid which is now the most prevalent in the UK has been described as a ‘Frankenstein’ variant. The World Health Organisation has issued a statement saying the XFG variant, also dubbed ‘Stratus’, will likely become the dominant variant soon, with symptoms different to the classic heavy cough and tiredness we’ve come to associate with Covid.

Dr Kaywaan Khan, Harley Street GP and founder of Hannah London Clinic, toldCosmopolitan UK: “Unlike other variants, Stratus has certain mutations in the spike protein which could help it evade antibodies developed from prior infections or vaccinations. Despite this, it is important to mention that Stratus seems to be no worse than earlier Omicron variants in terms of illness, hospitalisations, or deaths.”

Dr Khan said Stratus does not appear to make people 'more ill' than previous strains. But he said there is one unique symptom, adding: "One of the most noticeable symptoms of the Stratus variant is hoarseness, which includes a scratchy or raspy voice." Dr Khan said in general, the symptoms of Stratus tend to be 'mild to moderate'.

The latest Covid-19 variant is known as XFG (“Stratus”), which is often called a “Frankenstein variant”because it’s a mix-and-match of different virus types, or has many changes. This basically means it’s a new version built from parts of others.

Data from the UK Health Security Agency (UKHSA), shows Stratus has now become the dominant Covid strain in England. The variant has gone from accounting for about 10 per cent of all Covid cases in May to almost 40 per cent three weeks later in mid-June.

Stratus - a descendent of the already super virulent Omicron - is what is known as a Frankenstein or ‘recombinant’ strain. This means it emerged when a person was infected with two Covid strains at once which then became a new hybrid variant.

Professor Lawrence Young, a virologist at Warwick University, told MailOnlineboth strains of Stratus - the original XFG and spin-off called XFG.3 - are ‘rapidly spreading’. “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.

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“Given that immunity to Covid iswaning 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. This could lead to a new wave of infection but it’s difficult to predict the extent of this wave.’

However, he added that there is currently no evidence Stratus causes more severe illness and getting a Covid vaccine was ‘very likely’ to offer protection from severe illness and hospitalisation. “Frankenstein variant” typically describes strains like Omicron and its descendants, including NB.1.8.1 (nicknamed “Nimbus”) and XFG (“Stratus”), or even hybrids such as “Deltacron”.

Medics have warned that anyone with a‘razor blade’ throat could have Nimbus. Dr Michael Gregory, regional medical director for NHS England in the North West recently said: “The variant looks to be spreading rapidly within communities, with top symptoms being a ‘razor blade’ sore throat and swollen neck glands.”

How are these 'Frankenstein' variants different from other strains?

“Frankenstein” variants, encompassing Omicron and its sub-lineages like ‘Nimbus’ and ‘Stratus’, are characterised by a substantial number of mutations, particularly within the spike protein vital for cellular entry. Some, like the “Deltacron” variants, are literal hybrids, formed through the recombination of different existing strains - Delta and Omicron - within a single infected individual.

These extensive genetic alterations can enhance transmissibility and potentially enable immune evasion. Early data from the UK indicates that some of these highly mutated variants, such as BA.2.86, demonstrate similar levels of antibody escape compared to other circulating variants, with no evidence suggesting they cause more severe illness.

What are the common symptoms associated with these variants?

The symptoms observed with newer COVID-19 variants, including those informally dubbed “Frankenstein” variants, largely mirror those of previous Omicron subvariants. These commonly include upper respiratory symptoms such as fever, cough, sore throat, runny nose, and sneezing.

Other frequently reported symptoms involve 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 to be less prevalent in Omicron infections.

It is important to remember that symptom presentation can vary widely among individuals.