Urgent Warning Over New Covid-19 Variant NB.1.8.1 as Cases Rise in UK and Abroad

Health authorities have issued an urgent warning over a newly identified Covid-19 variant, NB.1.8.1, which experts believe may be more infectious than earlier strains. First detected in January 2025, the variant has since spread to 22 countries, including the UK, where cases have recently been reported in Wales.

NB.1.8.1 is a sub-lineage of the Omicron variant and has shown a rapid increase in prevalence globally. It now makes up approximately 10.7% of all submitted Covid-19 samples worldwide—up from just 2.5% a month earlier. The variant has also been identified in popular travel destinations for UK residents such as Thailand, the Maldives, and Egypt. Other countries experiencing rising case numbers include Ireland, the United States, Australia, and various parts of Europe.

The variant has been officially classified as a “variant under monitoring” by international health agencies due to its notable mutations and global spread. Despite the rise in cases and hospitalisations in areas where NB.1.8.1 is prevalent, current data does not suggest that it leads to more severe illness compared to other variants in circulation.

Health experts emphasize that currently approved Covid-19 vaccines are expected to remain effective against NB.1.8.1 in preventing both symptomatic and severe illness. As of now, there are no new travel restrictions associated with the variant, and the World Health Organization (WHO) has not recommended any such measures.

Authorities continue to monitor the situation closely, urging the public to stay informed and up to date with vaccinations, especially as summer travel increases. Individuals experiencing symptoms are advised to test and isolate when necessary to help limit further transmission.

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New Covid-19 Variant NB.1.8.1 Spreading Rapidly Worldwide

Health authorities have issued an urgent warning over a new Covid-19 variant, NB.1.8.1, which may be more infectious than earlier strains. First detected in January 2025, the variant has now been found in 22 countries, including the UK, with confirmed cases in Wales.

The World Health Organization (WHO) reports that NB.1.8.1 is particularly prevalent in Europe, the Western Pacific region (including Asia and Australia), and North and South America. The variant has become dominant in China and Hong Kong, according to Professor Laura Herrero of Griffith University, Australia.

NB.1.8.1 is a sub-lineage of Omicron and has seen a rapid global rise, now accounting for about 10.7% of all submitted Covid-19 samples, up from just 2.5% a month earlier. It has also been tracked in popular British holiday destinations, such as Thailand, the Maldives, and Egypt, as well as Ireland, the U.S., and Australia.

Common symptoms of NB.1.8.1 include sore throat, fatigue, fever, mild cough, muscle aches, and nasal congestion. Gastrointestinal symptoms may also occur in some cases. However, the WHO states there is no evidence that the variant causes more severe illness compared to other Omicron strains.

Current vaccines are expected to remain effective against NB.1.8.1 in preventing both symptomatic and severe disease. There are no travel restrictions related to the variant, and the WHO does not recommend introducing any at this time.

The NHS advises anyone experiencing Covid-19 symptoms to stay at home and avoid contact with others for five days after a positive test, or three days if under 18, to help limit further spread.

Authorities continue to monitor the variant closely as case numbers rise globally.

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