Doctors have warned of a painful symptom of the latest Covid strain
More than five years after Covid-19 first hit the UK, a new variant of the virus is circulating.
The Nimbus variant, also known as NB.1.8.1, has been identified in 22 countries so far, and has been linked to spikes in Covid cases in India, Hong Kong, Singapore, and Thailand.
The UK Health Security Agency (UKHSA) confirmed on Thursday (June 5) that the Nimbus variant has been detected in the UK.
Health officials said NB.1.8.1 has so far only been detected in small numbers within the UK, with 13 cases confirmed in England, but added that international data indicates that the variant is steadily accounting for growing numbers of global Covid cases.
The variant was first recorded on January 21 and the World Health Organisation (WHO) announced that the new NB.1.8.1 strain was “under monitoring” on May 23. By late April 2025, it made up roughly 10.7 per cent of all global infections – up from just 2.5 per cent four weeks prior, according to the WHO.
The WHO has said it is not advising that travel restrictions are imposed in light of the new variant.
Dr Gayatri Amirthalingam, UKHSA Deputy Director, said: “NB.1.8.1 has been detected in small numbers in the UK to date, but international data suggests that it is growing as a proportion of all COVID-19 cases.
“Based on the available information so far however, there is no evidence to suggest that this variant causes more severe disease than previous variants, or that the vaccines in current use will be less effective against it.”
Key symptoms of Covid NB.1.8.1 to look out for
Doctors have warned of one distinctive and painful symptom that could mean you have been infected with Covid.
Symptoms of the new strain are believed to be similar to earlier versions of the Covid virus, particularly of the Omicron variant, a highly transmissible version of Covid that first appeared in November 2021.
The Nimbus variant is a sub-variant of Omicron, which tends to cause mostly mild symptoms like a runny nose, sore throat, and other cold-like symptoms, as opposed to lower respiratory tract symptoms.
According to Dr Naveed Asif, GP at The London General Practice, the NB.1.8.1 variant has a distinctive symptom, a severe sore throat known as a “razor blade sensation”. This is a sharp, stabbing pain when you swallow, often at the back of the throat.
Other common symptoms include fatigue, mild cough, fever, muscle aches and congestion, adds Dr Asif.
“However, symptoms can vary widely so vigilance is key,” warns Dr Asif.
The NHS says common symptoms of Covid-19 include:
- A high temperature or shivering (chills)
- A new, continuous cough
- A loss or change to your sense of smell or taste
- Shortness of breath
- Feeling tired or exhausted
- An aching body or a headache
- A sore throat, blocked or runny nose
- Loss of appetite, feeling sick or being sick
- Diarrhoea
There are currently no Covid-19 restrictions in the UK, but Brits have been advised by the UKHSA to stay at home if they have symptoms of the virus.
