More than 1,000 monkeypox cases have been reported to the World Health Organisation as it spreads to nearly 30 countries outside of Africa where it had been more commonly found.
There have been 18 additional cases of monkeypox in England, bringing the total to 305, the UK Health Security Agency (UKHSA) reported on Wednesday.
WHO Director-General Tedros Adhanom Ghebreyesus said the risk of monkeypox becoming established in these non-endemic countries was “real but preventable” at this point.
Twenty-nine countries so far have reported cases in the current outbreak which began in May.
None have reported deaths so far.
At a media briefing in Geneva, Tedros also said there had been more than 1,400 suspected cases of monkeypox this year in Africa and 66 deaths.
“It’s an unfortunate reflection of the world we live in that the international community is only now paying attention to monkeypox because it has appeared in high-income countries,” he said.
He said the outbreak was showing signs of community transmission in some countries.
WHO recommends people with monkeypox isolate at home.
Cases are still predominantly among men who have sex with men, the WHO added, although cases in women have been reported.
The U.N. agency is working with organizations including UN AIDS and community groups to raise awareness and stop transmission.
Post-exposure vaccination, including for health workers or close contacts, including sexual partners - ideally within four days of exposure - may be considered for some countries, WHO added.
The vaccines being used are designed against smallpox, a related, more dangerous virus that the world eradicated in 1980, but also work to protect against monkeypox, studies have shown.
Anyone can get monkeypox, particularly if you have had close contact, including sexual contact, with an individual with symptoms, the UKHSA said.
Monkeypox is not normally a sexually transmitted infection but it can be passed on by direct contact during sex.
It can also be spread through touching clothing, bedding or towels used by someone with the monkeypox rash.
According to the UKHSA, monkeypox does not usually spread easily between people and the overall risk to the UK population remains low.
People with a rash with blisters are advised to contact a sexual health clinic if they have been in close contact with someone who has monkeypox or if they have travelled to West or Central Africa in the last three weeks.