A new subvariant of Covid, which is said to be highly infectious, has been detected in the UK for the first time. The World Health Organisation previously issued a warning about NB.1.8.1, which has rapidly risen to become responsible for more than 10 per cent of global cases of Covid.

It has been found in countries including Egypt, Thailand, the Maldives – and now the UK, with cases now confirmed in Northern Ireland and Wales. Thailand’s Government has urged people to wear masks, get vaccinated and wash hands to stop the spread of the virus.

The descendant of Omicron was first found globally in January this year and has now spread top the USA, Australia, China and Hong Kong. In China it is already the most dominant strain.

The Noirthern Ireland Public Health Agency says at least seven people have been diagnosed with the NB.1.8.1 strain of coronavirus. The Independent says there have also been cases in Wales.

The World Health Organisation has designated the NB.1.8.1 as a “variant under monitoring”. A WHO spokesperson said: ” SARS-CoV-2 continues to evolve, and between January and May 2025, there were shifts in global SARS-CoV-2 variant dynamics. At the beginning of the year, the most prevalent variant tracked by WHO at the global level was XEC, followed by KP.3.1.1.

“In February, circulation of XEC began to decline while that of LP.8.1 increased, with the latter becoming the most detected variant in mid-March. Since mid-April, the circulation of LP.8.1 has been slightly declining as NB.1.8.1 is increasingly being detected.”

Lara Herrero Associate Professor and Research Leader in Virology and Infectious Disease, at Griffith University said thanks to multiple mutations the new strain ‘may infect cells more efficiently than earlier strains’.

“But importantly, the WHO has not yet observed any evidence it causes more severe disease compared to other variants. Reports suggest symptoms of NB.1.8.1 should align closely with other Omicron subvariants.

“Common symptoms include sore throat, fatigue, fever, mild cough, muscle aches and nasal congestion. Gastrointestinal symptoms may also occur in some cases.”

The new strain is being found in large numbers in the Eastern Mediterranean. The WHO said recent increases have also been observed in Cambodia, China, Hong Kong and Singapore.

The report reads: “WHO recommends that countries remain vigilant, adapt to evolving epidemiological trends, and leverage COVID-19 management strategies to strengthen systems for all respiratory disease threats. Member States should continue offering COVID-19 vaccines in line with WHO recommendations.

“Based on the current risk assessment of this event, WHO advises against imposing travel or trade restrictions.”