UKHSA – Urgent public health message: Clade 1 mpox virus (MPXV) infection

August 16, 2024

MPXV is a virus from the same family as smallpox, that presents with a rash illness which may be mild and localised, or severe and disseminated. There are 2 distinct clades of the virus: Clade I and Clade II. Clade II MPXV is responsible for the global outbreak that began in 2022. Clade I MPXV is currently considered more severe than Clade II MPXV, leading to its classification as a high consequence infectious disease (HCID).

The symptoms of mpox begin 5 to 21 days (average 6 to 16 days) after exposure with initial clinical presentation of fever, malaise, lymphadenopathy and headache. Within 1 to 5 days after the appearance of fever, a rash develops, often beginning on the face or genital area and it may then spread to other parts of the body. The rash changes and goes through different stages before finally forming a scab which later falls off. Treatment for MPXV is mainly supportive

To view the list of countries that are affected by the disease click here.

Clinicians should be alert to the possibility of Clade I MPXV infection in patients presenting with suspected mpox where there is a link to the specified countries in the African region (as listed above).

Clinicians treating patients with suspected mpox who may meet the operational case definition of an HCID (as outlined above) should discuss this with local infection specialists.

For more information regarding Clade 1 mpox virus (MPXV) infection click here.