
UK health officials are looking into a mysterious case of mpox after a person in northeastern England tested positive for a rare strain called clade 1b. What makes this case unusual is that the patient has not traveled recently or been in contact with anyone known to have the disease.
The UK Health Security Agency (UKHSA) is trying to figure out how the person got infected. In past cases, people who caught mpox had either traveled to areas where the virus is common or had close contact with infected individuals.

Despite this unexplained case, Gillian Armstrong, the UKHSA’s mpox incident director, says the overall risk to the UK public remains low.
Mpox is a virus related to smallpox. It causes symptoms like fever, rash or blisters, swollen glands, and body aches. There are two main types of mpox: clade 1, which mostly affects children, and clade 2.
In 2022, the World Health Organization (WHO) declared a global health emergency due to the spread of clade 2, mainly among gay and bisexual men in Europe and the US. However, thanks to vaccines and awareness campaigns, the number of cases dropped, and the WHO ended the emergency in May 2023. At that time, there were about 87,400 cases worldwide and 140 deaths.
In 2024, a new outbreak involving clade 1 and a newer version called clade 1b spread in the Democratic Republic of Congo and nearby countries like Burundi, Kenya, Rwanda, and Uganda. Some cases have also appeared in Sweden, India, Thailand, Germany, and the UK.
So far, fewer than 10 cases of mpox clade 1b have been reported in England between last October and mid-February.