Five people have died from the monkeypox virus in Africa and more than 14,000 cases have been registered worldwide, World Health Organisation director general Dr Tedros Adhanom Ghebreyesus has said.
More than 60 countries in which monkeypox is not endemic have reported outbreaks of the viral disease.
Monkeypox, which spreads through close contact and was first found in monkeys, occurs mostly in western and central Africa and only occasionally spreads elsewhere.
“Monkeypox is still a serious public health challenge, and we urge contacts to take a break from any activities or events involving skin-to-skin contact, including sex, hugging, and kissing, to reduce the risk of the virus being passed on unknowingly,” said Dr Merav Kliner of the UK Health Security Agency.
On Thursday, the WHO will convene the second meeting of a committee that will decide whether the outbreak is a public health emergency of international concern, its highest level of alert.
"Regardless of the committee's recommendation, the WHO will continue to do everything we can to support countries to stop transmission and save lives," Dr Tedros said.
The outbreak has left some countries looking to procure vaccines. On Tuesday, Britain bought another 100,000 doses of vaccine to curb the spread of monkeypox as the number of cases across the country increased to more than 2,130, the majority of them in London.
The European Commission said on Monday it had secured about 54,000 doses of a vaccine developed by biotech company Bavarian Nordic.
The supply deal follows an initial contract signed in June, when the EU ordered about 110,000 doses of the company's vaccine.
"I am concerned by the increasing number of monkeypox cases in the EU," EU health commissioner Stella Kyriakides said.
There are now more than 7,000 cases reported in the EU, she said, a nearly 50 per cent increase from last week.
Under the initial order, the EU has so far delivered about 25,000 doses to six member states, the commission said.
Vaccine doses are delivered to countries based on their needs and the number of cases.