Nimbus, a highly contagious Covid variant, is on the rise in the UK with official UKHSA data suggesting infections have doubled in the space of just one month
A new strain of coronavirus is on the rise across the UK – with eight per cent of Covid tests analysed showing positive for the new ‘Nimbus’ variant. The highly contagious Nimbus is now Britain’s most dominant strain with official UKHSA data suggesting infections have doubled in the space of just one month.
The variant has been flagged in the UK, US and Australia and is linked to spikes in cases in India, Hong Kong, Singapore, and Thailand. Nimbus, known scientifically as N.B.1.8.1, is thought to be the most contagious variant of the virus yet with experts warning it could drive a wave of new cases this summer.
In its weekly report UKHSA also said there had also been a slight increase in hospital admissions for Covid to just over 1.5 admissions per 100,000 people. It follows warnings from British scientists earlier this month that Nimbus could lead to a surge in Covid cases.
They warned that many people’s immunity to the virus, built up from previous infections and older jabs, has likely faded meaning they could be at higher risk of falling ill.
Other data collected by the agency shows the total number of tests coming back positive for any type of Covid has increased to 6.8 per cent as of June 15, the latest available data. This is up from 5.6 per cent last month and represents the highest figure recorded so far this year.
The NHS is also recommending that anyone who suspects they may have Covid should isolate at home. The UKHSA has issued a warning about other symptoms too: “If you have symptoms of a respiratory infection, such as COVID-19, and you have a high temperature or do not feel well enough to go to work or carry out normal activities, you should avoid contact with vulnerable people and stay at home if possible.”
Further advice on how to live with Covid, including what to do if unable to self-isolate, can be found on the Gov.uk website.
What is different about the NB.1.8.1 Nimbus variant?
A recent preprint study indicates that the Nimbus variant binds more efficiently to human cells. This may allow for easier transmission and raise the possibility of it bypassing the immunity that most of the population has gained from previous infections.
The research surrounding Nimbus has yet to undergo peer review. However, it’s worth noting that the WHO has stated that existing Covid vaccines are effective against this new strain.
Salon reports there is no evidence at this stage suggesting that Nimbus leads to more severe illness than other Covid variants.
What is the new NB.1.8.1 Covid variant and where has it come from?
“The NB.1.8.1 variant, also referred to as Nimbus, is a new strain of the Covid-19 virus that has emerged due to mutations in its genetic material,” says Dr Naveed Asif, GP at The London General Practice.
It’s a sub-variant of Omicron, says Dr Chun Tang, GP at Pall Mall Medical.
“Variants like this pop up when the virus mutates, which is normal for viruses, especially ones that spread widely,” explains Tang. “NB.1.8.1 was first picked up in early 2025 and has since been detected in several countries, including the UK, China and US. It’s got some new mutations that scientists are keeping a close eye on.”
What are the symptoms to look out for?
Following a warning from the World Health Organisation (WHO). Sufferers of the new variant have described a “razor blade throat” symptom.
This reportedly feels like blades scratching the back of your throat every time you swallow. A very painful symptom and those suffering from it have been advised to get rest, fluids and painkillers to manage the condition.
Symptoms of Covid can encompass:
- A high temperature or experiencing chills – this implies feeling hot to the touch on your chest or back (there’s no need to take your temperature)
- A new, persistent cough – this refers to coughing excessively for over an hour, or having three or more bouts of coughing within 24 hours
- A loss or alteration in your sense of smell or taste
- Breathlessness
- Feeling fatigued or worn out
- Bodily aches
- A headache
- A sore throat
- A congested or runny nose
- Loss of appetite
- Diarrhoea
- Feeling nauseous or vomiting