Health experts are advising the public to be extra cautious following an increase in cases of an infectious illness in the UK. Recent data reveals that 16 confirmed cases of a specific strain of mpox have been identified in England.

According to Travel Health Pro, as of September 11, 2025, all 16 cases of clade Ib mpox in the UK have been in England. Many of these cases are linked to travel to regions where clade Ib mpox is prevalent.

This particular strain of mpox, more transmissible than the clade II variant that caused an outbreak in the UK in 2022, can be transmitted through close physical contact with mpox blisters or scabs.

Symptoms of mpox typically appear between five and 21 days post-exposure and include high fever, severe headaches, muscle and joint pain, swollen glands, shivering, fatigue, and the development of a rash within days.

The World Health Organization (WHO) warns that vulnerable groups such as young children, pregnant women, and individuals with compromised immune systems, particularly those with unmanaged HIV, are at higher risk of severe mpox complications, which could be fatal. However, most individuals recover within four weeks.

The UK Health Security Agency (UKHSA) reports that all 16 cases in the UK are concentrated in England and are linked to travel to areas where clade Ib mpox is circulating.

Several African nations have been experiencing an increase in clade Ib mpox cases since 2024, with imported cases also reported in Belgium, Canada, France, Germany, Sweden, and the United States.

If individuals exhibit symptoms of mpox after recent travel to central or east Africa and close contact with an infected person, the NHS recommends contacting 111 for assistance.

While mpox is considered rare, there are preventive measures individuals can take to reduce the risk of contracting and spreading the illness. These precautions include maintaining good hygiene practices.

Between 2023 and 2025, the UKHSA recorded 589 cases of mpox clade IIb in the UK. The agency attributes the lower case numbers during this period to the high vaccine coverage that has helped control the spread of the virus.