An mpox vaccine will be offered to thousands of men who have sex with men and some healthcare workers in the UK to boost protection against a form of the virus at the centre of an outbreak in parts of Africa, the government has said.
It has bought more than 150,000 doses and plans to offer them over time to groups at higher risk of becoming infected, starting with those who are unvaccinated.
During a worldwide outbreak of a mild form of mpox - formerly known as monkeypox - in 2022, many people in those groups were vaccinated.
There are no cases of the more worrying clade 1 mpox in the UK to date, and health officials say the risk to the UK population is low overall.
It is not clear when stocks of the vaccine, made by Bavarian Nordic, will arrive in the UK, but there are plans for the NHS to roll out vaccines in all four devolved nations.
The following groups are likely to be offered an mpox vaccination:
- gay, bisexual, or other men who have sex with men (GBMSM)
- certain healthcare workers in infectious disease units and sexual health services
- some humanitarian workers who travel to affected countries with active outbreaks
- close contacts of a confirmed case to lower their risk of becoming infected
About 10,000 men are thought to enter the GBMSM network every year, UK health officials say.
Mpox spreads from person to person through close contact with someone who is infected - through skin-to-skin contact, including sex, and by talking or breathing very close to the person who is ill.
The World Health Organization recently declared a global health emergency because of a surge in cases of clade 1 mpox in the DR Congo (DRC), where it has killed at least 635 people this year.
Medical staff on the front line treating mpox patients in eastern DRC told the BBC they are desperate for vaccines to stem the rate of new infections.
A particularly concerning mpox variant - called clade 1b - appears to be spreading quickly between people in the region and to surrounding countries.
Health Secretary Wes Streeting said the UK was also providing support to the DRC.
"The government is taking action to boost the UK’s resilience against clade 1 mpox, while providing critical support to countries at the centre of the outbreak."
He said steps were being taken to ensure the UK was prepared with "a robust vaccination programme" that protects those who may be at high risk.
The UK has announced £3m of funding to help efforts to tackle mpox and cholera outbreaks in the DRC, and prevent further spread to neighbouring countries.
Health officials have analysed what could happen if the more dangerous and transmissible clade 1b variant of mpox spreads to the UK.
There is a lot of uncertainty, but small clusters of cases or a controllable epidemic are thought to be the most likely scenarios.
The risk that this form of mpox could start spreading in the community is an unlikely scenario, a technical briefing has found.
In the meantime, the UK's plan is to vaccinate all those at higher risk of being infected and continue to monitor the situation very carefully.
Professor Susan Hopkins, chief medical advisor at the UK Health Security Agency, said: "We are preparing for any cases that we might see in the UK and vaccination plays a vital part in our defences."
She said rapid testing for mpox was available and protocols were being put in place to treat people with the infection and prevent spread to others.