A new ‘super-contagious’ Covid variant dubbed ‘Frankenstein’ is sweeping the UK – but how do you know if you’ve got it and is it more severe than other strains? The Mirror asked a medical expert for their advice
A new strain of Covid is spreading rapidly across the UK and is more transmissable to other people, meaning it could become the most dominant strain in weeks.
The Mirror asked Dr Thuva Amuthan, founder of Dr.Derme Skin Clinics, what symptoms to look out for when checking if you have the strain, known as ‘Stratus’.
Also known as the ‘Frankenstein’ variant, it presents symptoms similar to previous Omicron subvariants. Common signs include a sore throat (often described as ‘razor blade throat’), fever, fatigue, a cough, muscle aches and nasal congestion.
And some patients have also reported gastrointestinal symptoms such as nausea and diarrhea.
Dr Thuva Amuthan, founder of Dr. Derme Skin Clinics, said while it’s not yet the dominant strain it is a health concern because it’s more transmissible than other variants.
“NB.1.8.1 is a descendant of the JN.1 Omicron subvariant and has several mutations in its spike protein, enhancing its ability to bind to human receptors and potentially evade immunity from previous infections or vaccinations. This makes it more transmissible and capable of causing breakthrough infections,” the expert explained.
While it shares many symptoms with earlier variants of Covid, the presence of a particularly painful sore throat, often described as ‘razor blade throat,’ may be more pronounced with Stratus, otherwise known as NB.1.8.1.
According to the UK Health Security Agency (UKHSA), the Frankenstein variant has been detected in small numbers within the UK, although international data suggests its proportion among COVID-19 cases is increasing globally.
“Globally, NB.1.8.1 accounted for approximately 24% of all submitted SARS-CoV-2 sequences in the week ending 15 June 2025, a slight increase from 23% in the previous week,” Dr Amuthan added.
“In comparison, the LP.8.1 variant was the most prevalent globally during the same period, accounting for 26% of sequences, although this represented a decrease from 28% the week before.”
While Frankenstein may not be the most dominant strain yet, it’s more transmissible than some previous variants because its mutations allow it to spread more efficiently, contributing to its rapid emergence in multiple countries.
“NB.1.8.1 has demonstrated a higher capacity for immune evasion, meaning it can infect individuals who have been vaccinated or previously infected,” the doctor noted.
“However, current vaccines still offer protection against severe disease. Current data suggests that it does not lead to more severe illness compared to earlier Omicron subvariants. Most infections are mild, especially among vaccinated individuals.
“It’s crucial to continue monitoring emerging variants like NB.1.8.1. Staying up-to-date with vaccinations, practicing good hygiene, and seeking medical advice when experiencing unusual symptoms remain key strategies in managing the ongoing pandemic.”
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