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Mpox (monkeypox)


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Mpox (monkeypox) is a rare disease caused by infection with the mpox virus. The virus is related to but different from the ones that cause smallpox and cowpox.

Mpox occurs mostly in west and central Africa. However, some cases have been reported in the UK, Europe and other countries. Since May 2022 there has been an outbreak of mpox affecting the UK and other countries.

The risk of catching mpox is currently low in Wales.

More Information can be found below:

More information about the disease and signs and symptoms can be found at this link:

NHS 111 Wales - Health A-Z: Monkeypox

Stay at home and call 111 for advice if you think you might have mpox.


Treatment for mpox

Mpox is usually mild and most people recover within a few weeks without treatment.

But, if your symptoms are more severe and you become unwell, you may need treatment in hospital.

The risk of needing treatment in hospital is higher for:

  • older people
  • young children
  • people with a condition or who are taking a medicine that affects their immune system

Because the infection can be passed on through close contact, it's important to isolate if you're diagnosed with it.

You may be asked to isolate at home if your symptoms are mild.


Vaccination to protect against mpox

As mpox is caused by a virus similar to the one that causes smallpox, vaccines designed for smallpox should give a good level of protection against mpox.


Eligibility for the vaccine



The NHS is offering smallpox (MVA) vaccination to people who are most likely to be exposed to mpox.

People who are most likely to be exposed include:

  • healthcare workers caring for patients with confirmed or suspected mpox
  • gay and bisexual men, specifically those receiving PrEP or that have recently contracted a STI

The JCVI recommended that during periods of supply constraint, post exposure vaccination offers should be prioritised. Post exposure vaccination for contacts will be prioritised for those at greater risk of severe disease, including children under the age of five, pregnant women and people who are severely immunosuppressed. In addition, people eligible for pre-exposure vaccination, for example high risk gay and bisexual men, may be offered post-exposure vaccination.

In September 2022, due to the number of vaccines already given, the reducing incidence and the current vaccine supply the JCVI agreed that the next priority is to offer a second dose to gay, bisexual and men who have sex with men at highest risk from around 2-3 months after their first dose.  This will aim to provide longer lasting protection and to protect the community against subsequent introduction from countries where the virus is still circulating at higher levels.

We urge everyone who is eligible for the vaccine to take it up when they receive their invite. 

Mpox FAQ's


About the vaccine

The vaccine contains a virus which has been modified so that it cannot grow in the human body. This Modified Vaccinia Ankara (MVA) vaccine was developed as a much safer form of the smallpox vaccine used widely in the UK and abroad into the 1970s. The MVA vaccine does not contain smallpox virus and cannot spread or cause smallpox.

In September 2019, the Food and Drug Administration (FDA) in the US approved MVA-BN (Jynneos®) (the US labelled equivalent of Imvanex®) for the prevention of monkeypox as well as smallpox (FDA, 2019). The vaccine has recently been authorised for active immunisation against monkeypox in adults in the UK by the Medicines and Healthcare Products Regulatory Agency (MHRA): ( This should not make any difference to you, as your health care professional is recommending the vaccine in line with national advice.

The UK Health Security Agency (UKHSA) and the Joint Committee on Vaccination and Immunisation (JCVI) recommends the use of MVA vaccine as part of the response to cases of mpox.

The smallpox vaccine available is manufactured by – Bavarian Nordic (MVA-BN). It is currently distributed under 2 brand names, although it is the same vaccine.

The brand names are:

  • Imvanex
  • Jynneos

The MVA-BN vaccine has been used in the UK in response to the current and previous incidents.

You can be given this vaccine whether or not you have received a smallpox vaccination in the past.

The vaccine will be injected either under your skin or into the skin, preferably into the upper arm, by your health care practitioner.


Does the vaccine work?

After 2 doses of vaccine, almost all people develop antibodies and should therefore have a good level of protection against mpox. It is less clear what level of protection you get from a single dose – this may be a reason to avoid high risks until after the second dose. Vaccines work in different ways. One dose may not completely prevent infection but even if you catch mpox, the symptoms should not be as bad. The first dose prepares your immune system so it can respond much more quickly if you come into contact with mpox. The vaccine also takes time to work. It might start to work after a few days and should reach the highest protection by about 4 weeks. Because there are currently limited supplies of the vaccine, the NHS will start by giving one dose to as many eligible people as possible. This is a fair way to provide some protection to the whole community. As more vaccines become available, a second dose will be given to those at highest risk. This will be at least 2 to 3 months after the first vaccine. A longer time between the first and second doses should improve your long term protection. Even after 2 doses you should continue to be aware of the risks and symptoms of mpox. If you develop symptoms, stay at home and call NHS 111 or a sexual health clinic.


What are the side effects of the MVA vaccine?

The vaccine has a very good safety profile. Like all vaccines it can cause side effects, but most of these are mild and short-lived and not everyone gets them.  

Side effects may be more common in people who have previously received a dose of live smallpox vaccine.


Side effects of the vaccine

Like most vaccines, the vaccine can sometimes cause mild side effects, including:

  • headache
  • chills, fever
  • aching muscles
  • pain in the joints or extremities
  • feeling sick, or loss of appetite
  • tiredness
  • pain, redness, swelling, hardness or itching at the injection site

Other reactions are rare. If your symptoms get worse or if you are concerned, call NHS 111 Wales on 111 or your GP surgery. Calls to NHS 111 Wales are free from landlines and mobile phones.

You can report suspected side effects of vaccines and medicines through the Yellow Card scheme. You can do this online at or by calling the Yellow Card scheme hotline on 0800 731 6789 (Monday to Friday, 9am to 5pm).


Information for the public

If you would like to learn more about the vaccine or the disease it protects against, a few information resources are available to help. You can also call NHS 111 or your GP practice for advice if you have any questions.

Protecting you from Monkeypox A4 Leaflet - English

Protecting you from Monkeypox A4 Leaflet - Cymraeg