A smallpox vaccine is being offered to some healthcare workers and others who may have been exposed to monkeypox in the UK after a smattering of cases.
In the UK, nine cases of the West African strain have been reported so far. A handful more cases have been confirmed in parts of Europe.
There isn't a specific vaccine for monkeypox but a smallpox vaccine does offer some protection, a UK Health Security Agency (UKHSA) spokesperson said.
Data shows that vaccines that were used to eradicate smallpox are up to 85% effective against monkeypox, according to the World Health Organisation (WHO).
"Those who have required the vaccine have been offered it," the UKHSA spokesperson added, without disclosing specifics on how many people have been vaccinated so far.
Monkeypox is a usually mild viral illness, characterised by symptoms of fever as well as a distinctive bumpy rash.
There are two main strains: the Congo strain, which is more severe - with up to 10% mortality - and the West African strain, which has a fatality rate of about 1%.
First identified in monkeys, the viral disease typically spreads through close contact and largely occurs in west and central Africa.
It has rarely spread elsewhere, so this fresh spate of cases outside the continent has triggered concern.
Some countries have large stockpiles of the smallpox vaccine as part of pandemic preparedness, including the United States.
Copenhagen-based drugmaker Bavarian Nordic on Thursday said it had secured a contract with an undisclosed European country to supply its smallpox vaccine, Imvanex, in response to the monkeypox outbreak.
