Mpox (Monkeypox)

Mpox (Monkeypox) is a rare disease that is caused by infection with MPXV virus. It causes a high temperature and a rash lasting a few weeks.

There are 2 types of MPXV virus: Clade I and Clade II.

Clade II MPXV is responsible for the global outbreak that began in 2022. Clade I MPXV is considered more severe and is currently affecting countries in Central and East Africa.

Since January 2023, Clade II mpox is no longer considered a high consequence infectious disease (HCID). Clade I mpox remains an HCID.

Mpox does not spread easily between people unless there is very close contact. The virus is transmitted through skin-to-skin contact (touch, kissing or sex), breathing in virus from someone close by who is coughing or sneezing, or contact with contaminated material such as clothing, bedding or towels.

Anyone with a history of contact with a case of mpox, or with an undiagnosed rash and recent travel to an affected country, should contact their GP for advice.

As of August 2024, no cases of Clade I mpox have ever been detected in the UK.

Incubation

The incubation period is the time between contact with the infected person and when the first symptoms appear. The incubation period for mpox is between 5 and 21 days.

Symptoms

Mpox infection is usually a self-limiting illness, and most people recover within several weeks. However, severe illness can occur in some individuals.

The illness begins with:

  • fever
  • headache
  • muscle aches
  • backache
  • swollen lymph nodes
  • chills
  • exhaustion

Within 1 to 5 days after the appearance of fever, a rash develops, often beginning on the face or genital area and then spreading to other parts of the body. The rash changes and goes through different stages before finally forming a scab which later falls off.

An individual is contagious until all the scabs have fallen off and there is intact skin underneath. The scabs may also contain infectious virus material.

Diagnosis

Clinical diagnosis of mpox can be difficult, and it is often confused with other infections such as chickenpox. A definite diagnosis of mpox requires assessment by a health professional and specific testing in a specialist laboratory.

Treatment

Clade 11 mpox is usually mild and most of those infected will recover within a few weeks without treatment.

Smallpox vaccine can help to control outbreaks and protect high risk individuals.

Antiviral medicines can be used to treat severe cases.

Reference sources:

Published: September 2022
Updated: August 2024