Mpox outbreak: community transmission of clade I mpox virus outside the African Region

The UKHSA has advised that overall probability of importation of clade I mpox virus into the UK has increased from medium to high while risk to short-term travellers remains low

• This updates the news item of 10 September 2025

Community transmission of clade Ib mpox has been reported in countries with strong travel links to the United Kingdom (UK). In October 2025, health authorities in Spain, USA (California), Netherlands, Italy and Portugal reported small numbers of locally-acquired clade Ib mpox cases, all with no travel history or links to confirmed cases which may indicate undetected clade Ib mpox spread in these countries [1].

Background

Mpox is an infection caused by the monkeypox virus (MPXV). There are two distinct clades of the virus: clade I (with subclades Ia and Ib) and clade II (with subclades IIa and IIb). Infection typically causes a mild, self-limiting illness with a characteristic rash, but in some circumstances infection can be fatal.

In May 2022, a global outbreak of clade IIb mpox emerged, mainly affecting gay, bisexual and other men who have sex with men (GBMSM). Cases continue to be reported at low levels in many countries worldwide, including the UK [2].

Before 2024, clade I mpox was only reported in five countries in central Africa [3]. The upsurge of clade I mpox (mostly clade Ib) in the Democratic Republic of Congo (DRC), which began in 2023 and subsequently spread to additional countries in 2024, was the first known expansion of its geographical range [4].

On 4 September 2025, the World Health Organization (WHO) advised the mpox situation no longer represented a public health emergency of international concern (initially declared in August 2024). Lifting this emergency declaration does not mean the threat is over, and WHO global response will continue [5].

Most cases of mpox are reported from Africa, where there has been a sustained downward trend in recent months [6]. However, certain countries are still reporting high case numbers, including those with close travel links to the UK.

As of 7 November 2025, a total of 46,923 confirmed cases of mpox (all clades) had been reported from 27 countries in Africa (including 200 deaths) in the previous 12 months. The majority of these cases were reported from DRC (clades I and II b), Uganda (clade Ib) and Sierra Leone (clade II) [3].

On 27 October 2025, a small number of locally-acquired clade Ib mpox cases have been reported in Spain, the USA (California), the Netherlands, Italy, and Portugal, with no connection to countries with known clade Ib mpox transmission [1]. This suggests there is now community transmission of clade Ib mpox outside the African region. WHO defines community transmission as at least one reported case with no epidemiological link to travel or contact with a traveller from a country with known mpox transmission [3].

Previously, community transmission of clade Ib mpox was in Africa, most notably the DRC, Uganda, Burundi and Kenya [3, 6]. Before October 2025, cases of clade Ib mpox detected outside Africa were primarily travel-related. Limited local transmission of clade I (for example, in household contacts of infected returned travellers) was reported in Australia, Belgium, China, France, Germany, Thailand, Qatar and the UK [7].

There is also an increasing trend of cases detected outside Africa, with travel links to countries outside of Africa, both where confirmed cases have been reported (Pakistan, Oman, Thailand and UAE), and in two countries where no confirmed cases have been reported (Lebanon and Nepal) [1].

Of the clade Ib cases recently identified in Europe and the USA, most have been in GBMSM, a population in which clade Ib mpox transmission has not previously been observed [1].

Situation in the UK

As of 7 November 2025, a total of 18 clade Ib mpox cases have been reported in the UK – 17 in England and one in Scotland [8]. Most of these cases are associated with travel abroad, with links to countries with evidence of community transmission of clade Ib mpox. Transmission to close contacts in two UK households with no further onward spread was observed, resulting in four secondary cases; three of these received vaccination 10 days post-exposure and before testing positive. Most clade Ib mpox cases have a known exposure through sexual contact overseas [1].

For latest information on UK mpox cases see UKHSA data dashboard.

While the overall probability of importation into the UK has increased from medium to high, UKHSA has advised that for most general short-term travellers to affected areas, the risk remains low.

For those staying within households in areas directly affected by outbreaks, with sexual contacts or exposed to cases (for example, through occupation) the risk is medium.

The risk of onwards transmission in the UK is likely to be controlled to some degree by the existing vaccination programme and remains low to medium at present. However, there are significant uncertainties relating to the circulating virus properties, groups at risk and the level and duration of immunity from natural infection or vaccination [1].

As of 7 November 2025, there have been no cases of clade Ia mpox reported in the UK [3].

An overview of mpox epidemiology indicating where there may be a risk of clade I and clade II mpox exposure is available at GOV.UK – Mpox: affected countries.

The latest epidemiological data on mpox (all clades) can be found on the WHO mpox surveillance dashboard.

Please check our Outbreak Surveillance database for updated information on recent outbreaks and mpox cases.

Mpox symptoms and spread

Most infected people experience a mild self-limiting illness, with spontaneous and complete recovery usually two to four weeks after the start of symptoms, although recovery can take longer. However, severe illness can occur and sometimes results in death. Risk of severe disease is higher in children, pregnant women and severely immunocompromised individuals (those with a weakened immune system).

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 lesions then usually appear one to five days after the first symptoms. The rash (spots, blisters or ulcers) may begin anywhere on the body and spread to other parts of the body. This can include the face, mouth, genitals and anus. The number of sores can range from one to several thousand.

See UK Health Security Agency (UKHSA) guidance Mpox: background information for further details, including images of mpox rash.

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

Person-to-person spread can occur through:

• touching the rash, skin lesions (spots, blisters or ulcers) or scabs of someone with mpox (including during sexual contact, kissing, cuddling or other skin-to-skin contact)
• contact with body fluids such as saliva (spit), snot, mucus or semen/vaginal fluids of someone with mpox
• contact with clothing or linens (such as bedding or towels) or other objects and surfaces used by someone with mpox

There is a potential risk of mpox spreading through close and prolonged face-to-face contact (for example while talking, breathing, coughing or sneezing close to one another) with someone with mpox, however there is limited evidence for this.

In parts of central and eastern Africa, spread of mpox may also occur when a person comes into close contact with an infected animal, usually a rodent such as a mouse or a rat. Mpox has not been detected in animals in the UK.

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 where mpox cases have been reported: GOV.UK – 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 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.
• Make sure you know the symptoms of mpox and how mpox is transmitted.

Vaccination

The UK does not currently recommend pre-travel mpox vaccination for most travellers. General risk for most travellers is considered low, as close contact with communities with transmission of mpox would not be usual [9]. 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.

A routine mpox vaccination programme was launched on 1 August 2025 for GBMSM at highest risk of infection and other individuals who have frequent close and intimate contact with the GBMSM network. Eligible individuals should be identified through local authority commissioned sexual health services: NHS sexual health clinics.

To check if you are eligible or to book an appointment, visit Mpox vaccine – NHS.

Please refer to the UKHSA Green Book – Immunisation against infectious disease for updated information about mpox vaccine eligibility.

The Joint Committee on Vaccination and Immunisation (JCVI) continues to review latest data on the current situation and will continue to update vaccination recommendations accordingly.

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 a 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.
• 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 mpox.
• If you are in areas where mpox is endemic avoid contact with animals, especially rodents and do not eat, cook or prepare any type of raw or wild meat (bushmeat) or any meat from unknown sources.

If you are a UK traveller and you are experiencing symptoms abroad, you should:

• Limit your contact with other people.
• Get medical advice locally, ringing ahead before going to a healthcare facility. If you are not able to call ahead, inform a staff member as soon as you arrive that you are concerned about mpox.
• Check with a health professional that you are fit to travel.
• If you are diagnosed with mpox, do not have sex until your symptoms fully resolve and use a condom during sex for 12 weeks after infection. This is to reduce the risk of spreading MPXV to partners.

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

For more information on the risk of mpox and sex, please see the WHO 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 virus.

When you return

If you have just arrived at a UK airport or port of entry having recently travelled to any of the countries affected by mpox, 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.

Advice for health professionals

Health professionals who suspect a case of mpox should follow the Mpox: guidance on when to suspect a case of mpox. Guidance is available on diagnostic testing, contact tracing and de-isolation and discharge of cases.