
More than five years after Covid-19 hit the world, 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 an increase in Covid cases in the US, India, Hong Kong, Singapore and Thailand.
The United Kingdom Health Safety Agency (UKHSA) has confirmed that the Nimbus variant has also been detected in the United Kingdom.
The variant was first recorded on January 21, and the World Health Organization (WHO) announced that the new strain NB.1.8.1 was “under surveillance.” By the end of April 2025, it accounted for approximately 10.7 percent of all global infections.
Dr. Gayatri Amirthalingam, Deputy Director of UKHSA, said: "NB.1.8.1 has been detected in the UK, but international data suggests it is increasing as a proportion of all COVID-19 cases.
"However, based on the information available to date, there is no evidence to suggest that this variant causes more severe disease than previous variants, or that vaccines in current use will be less effective against it."
Doctors have warned of a distinctive and painful symptom that could mean you've been infected with Covid.
The symptoms of the new strain are believed to be similar to previous versions of the Covid virus, particularly 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 mainly mild symptoms such as a runny nose, sore throat, and other cold-like symptoms.
According to Dr. Naveed Asif, a general practitioner, Variant NB.1.8.1 has a distinctive symptom, a severe sore throat known as a “razor burn.” This is a sharp, stabbing pain when swallowing, often in the back of the throat.
Other common symptoms include fatigue, mild cough, fever, muscle aches and congestion, adds Dr Asif.