The World Health Organisation (WHO) has said that the new COVID-19 variant NB.1.8.1 is causing more infections worldwide.

Already, the WHO has designated NB.1.8.1 as a “variant under monitoring” due to its increasing global prevalence and potential to evade immunity from previous infections or vaccinations.

The rise in cases is primarily in the Eastern Mediterranean, Southeast Asia, and Western Pacific regions.

The new strain was designated as a “variant under monitoring” by the WHO last week, while the U.S. Centres for Disease Control (CDC) confirmed a small number of cases circulating in the United States.

This variant has also been detected in travellers arriving in the U.S., including in California, Virginia, Washington, and New York.

According to the WHO, the variant spreads easily but does not appear to cause more severe illness.

First detected in late January, NB.1.8.1 is a descendant of the Omicron JN.1 lineage and has seen a sharp rise in global cases in recent weeks.

According to the most recent data from the WHO, NB.1.8.1 accounted for 10.7% of global sequenced COVID cases between April 21 and April 27—up from 2.5% just a month earlier.

In an update on May 28, the WHO noted that the variant is driving up cases in parts of the world and is currently spreading in Southeast Asia, the Western Pacific regions, and the Mediterranean.

The organisation stated that the recent increases have been observed in four countries and areas to date, particularly in Cambodia, China, Hong Kong, and Singapore.

WHO explained that the variant LP.8.1 is currently the dominant version worldwide, but both LP.8.1 and NB.1.8.1 have not shown signs that they would cause an “increased public health risk” when compared to other circulating variants.

In a recent update, the Chinese Centre for Disease Control (CDC) said that NB.1.8.1 makes up the majority of cases in China, while some Chinese doctors have gone on record in state-run media to say that one symptom being reported is a sharply painful sore throat.

The centre has not reported the rate of severe cases, hospitalisation rate, or mortality rate.

The Chinese CDC has, over the years, been accused of not being transparent with its case and death figures throughout the pandemic.

WHO’s recent update noted that new variant cases have increased in the Western Pacific region, which includes China.

Officials in South Korea on Friday said its government is closely monitoring COVID-19 cases in China and Hong Kong.

In Australia, genomic sequencing indicates that NB.1.8.1 accounts for over 40% of cases in Victoria and is now the dominant strain in wastewater samples collected in Perth.

NB.1.8.1 is believed to be more transmissible than earlier strains. Research suggests it may infect cells more efficiently and partially sidestep existing immunity. Common symptoms include sore throat, fatigue, fever, mild cough, muscle aches, and nasal congestion. Gastrointestinal symptoms may also occur in some cases.