Mpox outbreak in Africa: clade I mpox virus infection

Mpox outbreak continues to meet the WHO criteria of a public health emergency of international concern (PHEIC)

• This updates the news item of 8 November 2024

The second meeting of the WHO International Health Regulations (2005) Emergency Committee regarding the upsurge of mpox cases in 2024 met on 22 November 2024 [1]. The Committee agreed that the situation continued to meet the criteria of a public health emergency of international concern (PHEIC) initially declared in August 2024 [2]. Standing and additional temporary recommendations have been extended until 20 August 2025. The WHO committee state that the event 'requires a coordinated international response' [1].

Background

Mpox is an infection caused by the virus MPXV. There are 2 distinct clades of the virus: clade I and clade II. Historically, clade I mpox has been associated with a higher risk of people with the infection developing severe illness or dying, compared to clade II. In May 2022, an outbreak of clade II mpox occurred globally. This outbreak predominantly affected gay, bisexual and other men who have sex with men.

Prior to 2024, clade I mpox had only been reported in 5 countries in central Africa. However, recent cases in additional countries within Central and East Africa mark the first known expansion of its geographical range, heightening the risk of spread beyond the region.

In 2023, the Democratic Republic of Congo (DRC) reported its highest number of clade I mpox suspected and confirmed cases on record. High case numbers have continued to be reported in 2024 with cases reported in 6 provinces including the capital Kinshasa [1]. Mpox clade Ib has also spread in neighbouring countries, including in Burundi (growing in the urban areas of Bujumbura and Gitega) and Uganda (growing in the capital Kampala) with established sustained community transmission; and Kenya and Rwanda with clusters of mpox cases [1]. Travel-related cases of MPXV clade Ib infection, mostly linked to countries where outbreak have been reported, have been detected in the following WHO Regions – African Region (Zambia, Zimbabwe); Americas Region (United States of America, Canada); European Region (Germany, Sweden, United Kingdom) and South-East Asian Region (India, Thailand) [1, 3, 4]. India detected one case of clade Ib mpox in a traveller from the United Arab Emirates (UAE). No case of clade Ib mpox has been reported in the UAE [5]. Please check our Outbreak Surveillance database updated mpox cases.

As of 29 November 2024, the UK Health Security Agency (UKHSA) have reported a total of five confirmed clade Ib mpox cases since October 2024 [6]. Two of the cases were reported in (unconnected) travellers who had visited countries in Africa where clade Ib has been circulating. Three further cases were subsequently detected in household contacts of the first case [6]. The risk to the UK population remains low although occasional imported cases are expected.

Information on the countries in Africa where clade I cases have been reported is available at GOV.UK - Clade I mpox: affected countries.

Mpox symptoms and management

Mpox can be transmitted when a person comes into close contact with an infected, human, animal or contaminated material.

Person-to-person spread can occur through:

• Direct contact with broken skin (even if not visible) or scabs (including during sexual contact, kissing, cuddling or other skin-to-skin contact).
• Contact with bodily fluids such as saliva, snot or mucous.
• Contact with clothing or linens (such as bedding or towels) or other objects and surfaces used by someone with mpox.

While more information is emerging, there is a potential risk of mpox spreading if you are close and prolonged face-to-face contact with an individual with mpox when they are talking, breathing, coughing or sneezing.

Spread of mpox may also occur when a person comes into close contact with an infected animal. Mpox has not been detected in animals in the UK.

The incubation period (time from infection to first symptoms) is between five and 21 days. The first symptoms of mpox include:

• a high temperature
• a headache
• muscle aches
• backache
• swollen glands
• shivering (chills)
• exhaustion
• joint pain

A rash or pus-filled lesions then usually appear 1 to 5 days after the first symptoms. The rash (spots, blisters or ulcers) often begins on the face, then spreads to other parts of the body. This can include the mouth, genitals and anus. The number of sores can range from one to several thousand.

Most patients experience a mild self-limiting illness with spontaneous and complete recovery seen within 3 weeks of onset. However severe illness can occur and sometimes results in death. The risk of severe disease is higher in children, pregnant women and severely immunocompromised individuals (those with a weakened immune system).

Advice for travellers

Before you travel

Check Foreign Commonwealth and Development Office (FCDO) advice on whether it is advised to travel to your intended destination. This also includes information on entry requirements, safety and security.

Information is available on countries in Africa where clade I cases have been reported: GOV.UK: Clade I mpox: affected countries. However, the situation may change rapidly in different countries, and travellers need to remain vigilant to the risk of mpox from nearby countries where clade I mpox cases have not been reported to date.

Check our Country Information pages for the latest guidance on vaccination, malaria and other health risks. Our Outbreak Surveillance database will provide information regarding recent outbreaks and mpox cases.

Before travelling to affected areas, you should:

• Check with a health professional that you are fit to travel. In particular, pregnant and immunosuppressed people are known to be at higher risk of severe infection.
• Check your travel health insurance before you go.

Vaccination

The UK does not currently recommend pre-travel vaccination for mpox. However vaccination may be appropriate for certain specialist healthcare and humanitarian workers who go to affected countries to work within mpox response or sites with active outbreaks following a risk assessment.

Aid workers and health professionals planning humanitarian work in countries with outbreaks or isolated mpox cases should seek advice and training from their employer/organisation before travel. Any organisation deploying UK resident staff to areas affected by mpox clade I virus, in response to the outbreak should register with the UK Health Security Agency (UKHSA) Returning Workers Scheme (RWS) - see below.

The JCVI continues to review latest data on the current clade I mpox outbreak and will continue to update vaccination recommendations accordingly.

Please refer to the Green Book - Immunisation against infectious disease for further information about mpox vaccine eligibility.

While you are away

Mpox can be spread through close contact of any kind, including through sexual and non-sexual contact.

The risk of mpox is low for most travellers. You can reduce your risk while travelling by taking sensible precautions to protect yourself from infection:

• Avoid contact (including sexual contact) with anyone who is unwell or has an unusual rash.
• Wash hands often with soap and water or an alcohol-based hand sanitiser containing at least 60% alcohol. Keep your hands away from your eyes, nose, and mouth. If you touch your face, make sure your hands are clean.
• Talk to sexual partners about their sexual and general health and ask if they have any symptoms.
• Before you have sex, go to a party or event, check yourself for mpox symptoms, including rashes and blisters. If you have mpox symptoms, take a break from attending events or having sex until you've been assessed by a health professional.
• It can take up to three weeks for symptoms to appear after having contact with someone with mpox, so stay alert for symptoms after you have skin to skin or sexual contact with someone new.
• Everyone is encouraged to exchange contact details with sexual partners, to help stop further mpox spread when cases occur.
• Avoid touching items such as bedding/clothing and do not share eating utensils/cups, food or drink with anyone who has symptoms or has mpox.
• Avoid contact with animals, especially rodents.
• Do not eat, cook or prepare any type of raw or wild meat (bushmeat) or any meat from unknown sources.

UK travellers experiencing symptoms abroad should:

• Limit their contact with other people.
• Get medical advice locally, calling ahead before going to a healthcare facility. If they are not able to call ahead, they should inform a staff member as soon as they arrive that they are concerned about mpox.
• Check with a health professional that they are fit to travel.
• Anyone diagnosed with mpox should not have sex while they have symptoms, including lesions, and must use condoms for 12 weeks after infection. This is to reduce the risk of spreading MPXV to partners.

Travellers should follow local public health advice. They may need to self-isolate, be admitted to hospital or put into a quarantine facility until they are no longer considered infectious to other people. Travel to an mpox affected area may affect travel health insurance options. Travellers should discuss their plans with their travel insurance company before they go.

For more information on the risk of clade II mpox and sex, please see the public health advice for gay, bisexual and other men who have sex with men.

For advice for people living with HIV, see the British HIV Association (BHIVA) statement on mpox (monkeypox) virus.

When you return

If you have just arrived at a UK airport or port of entry having recently travelled to any of the mpox affected countries, and have any new spots, blisters or ulcers, you should speak to a member of port or border staff to get advice.

If you have visited one of the affected countries and develop symptoms within 21 days of returning to the UK, please isolate at home and call NHS 111 for advice, letting them know your travel history.

See current advice on the NHS mpox page.

Returning Workers Scheme

Any organisation deploying UK resident staff to areas affected by mpox clade I virus, in response to the outbreak should register with the UKHSA Returning Workers Scheme (RWS).

The current list of countries can be found here: Operational mpox HCID (clade I) case definition - GOV.UK (www.gov.uk). This list of countries may change in the future as the epidemiology of the current outbreak is rapidly evolving. Further information on the scheme is available here.

Advice for health professionals

Health professionals who suspect a case of mpox should contact the local infection clinician (microbiology, virology infectious disease and genitourinary medicine as appropriate). Infectious disease specialists should contact the Imported Fever Service to discuss testing and management. Guidance is available on diagnosis, testing and infection control measures and will continue to be updated. Specific guidance on managing cases of clade I mpox can be found here.