The WHO has warned over a surge in Covid cases with the new variant now responsible for more than 10 per cent of all infections.

By Neil Shaw, Assistant Editor

14:42, Thu, May 29, 2025 | UPDATED: 14:46, Thu, May 29, 2025

There has been a sharp increase in positive test results for Covid

There has been a sharp increase in positive test results for Covid (Image: undefined)

The World Health Organisation has designated the new strain NB.1.8.1 as a 'variant under monitoring' amid concern about the sharp rise in cases.

By late April 2025, NB.1.8.1 comprised roughly 10.7% of all submitted sequences – up from just 2.5% four weeks before. It is already the dominant strain in Hong Kong and China. 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'.

This strain has been identified in several countries, including Australia, the US, and it is suspected to be present in the UK as well, reports the Mirror.

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."

Holidaymakers could find themselves heading into a hotzone

Holidaymakers could find themselves heading into a hotzone (Image: undefined)

A World Health Organisation report warned: "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."

Lab tests are tracking the new strain as it spreads

Lab tests are tracking the new strain as it spreads (Image: undefined)

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The new strain is being detected in significant numbers in the Eastern Mediterranean, which includes popular tourist destination Egypt, as well as in South East Asia, including Thailand and the Maldives.

According to the WHO, recent increases have also been observed in Cambodia, China, Hong Kong, and Singapore.

The report advises: " 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."