U.K. health agency identifies new mpox strain in England

This image provided by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) shows a colourized transmission electron micrograph of mpox particles (red) found within an infected cell (blue). (NIAID via AP, File)

LONDON, United Kingdom -- The U.K. Health Security Agency (UKHSA) said Monday it had identified a new strain of the mpox virus in England in a person who had recently travelled to Asia.

“Our genomic testing has enabled us to detect this new mpox strain,” said Katy Sinka from the UKHSA, a government agency responsible for preventing and controlling the spread of infectious diseases.

The agency said it would continue to “assess the significance of the strain”, which had elements of both mpox subtypes: the more severe clade 1, and clade 2.

“Genomic sequencing showed that the mpox genome contained elements of clade Ib and IIb mpox,” the UKHSA said.

Mpox, previously known as Monkeypox, is a viral infection related to smallpox, causing fever, body aches and distinct skin lesions and can be deadly.

It can be transmitted to humans by infected animals but can also be passed between people through close physical contact.

“It’s normal for viruses to evolve, and further analysis will help us understand more about how mpox is changing,” said Sinka.

“It is of concern that there is an mpox case in the U.K., and of further concern that it is a new recombinant mpox virus,” said Trudie Lang, a University of Oxford researcher and the director of the Global Health Network.

“This case highlights that mpox is circulating globally and is evolving, as predictable with these viruses.”

Mpox was declared a public health emergency in August 2024 by the World Health Organization (WHO), after a two-pronged mpox epidemic broke out, primarily in the Democratic Republic of Congo.

The WHO lifted the status in September after a sustained decline in cases and deaths.

Lang explains that the virus has evolved, with previous strains being transmitted mainly from animals to humans.

An outbreak in Europe in 2022 was limited to close sexual transmission, mainly affecting gay and bisexual men, whereas the latest outbreak of clade 1b in 2024 was transmitted through close contact as well as sexual relations.

“The identification of a recombinant mpox strain containing elements of both clade I and clade II is precisely what experts in the field feared would happen,” said Boghuma Titanji, assistant professor of medicine at Emory University.

This year until the end of October, nearly 48,000 confirmed mpox cases worldwide have been reported to the WHO, including 201 deaths, from 94 countries.

The UK has an mpox vaccination programme for eligible groups, including people with multiple sexual partners and those who participate in group sex.

A “low level” of mpox cases have been identified in the U.K. since 2022, when clade 2 spread around the world.