A further ten cases of monkeypox have been diagnosed in the UK since May 4, all in London, bringing the total of new cases since the beginning of the year to 20.
Half of the new cases were in unvaccinated individuals and two in those who had only received one dose, said the UK Health Security Agency.
Five of the cases acquired the infection in the UK, four are thought to have acquired the infection abroad and one remains under investigation.
The new cases come just weeks before the vaccination programme is due to end by the close of July - prompting calls from sexual health campaigners for it to be extended.
Appointments for one dose of the vaccine will end on June 16, while those waiting for a second dose have until July 23 to get the dose.
Those eligible for the vaccine include gay, bisexual or other men who have sex with men who have multiple sexual partners, participate in group sex or attend sex on premises venues.
Katy Sinka, Head of Sexually Transmitted Infections at UKHSA, said: “It is clear from these latest statistics that mpox has not gone away.
“While mpox infection is mild for many, it can cause severe symptoms for some so it’s important people remain alert to the risks. Vaccination is key to reducing the severity of symptoms and preventing further transmission.
“Uptake of first doses has been strong but only around a third of those who have received their first dose have had their second dose so far.”
“While ten new mpox cases may seem small scale, it’s important to react quickly to ensure we don’t see another wave,” Ceri Smith, Head of Policy at sexual health charity Terrence Higgins Trust, said.
“That means ensuring the mpox vaccination programme for gay and bisexual men is extended – the current offer for mpox vaccination is due to be wound down at the end of July.”
Mpox is viral illness caused by the monkeypox virus. Symptoms include fever, headaches, swellings, back pain, aching muscles.
A prominent rash can also develop, beginning on the face, then spreading to other parts of the body.
Those with symptoms are advised to refrain from sex or close contact with others to avoid passing the virus on.
The virus is normally linked to travel to countries where it is endemic.
However, last year a global outbreak occurred, affecting mainly among gay, bisexual, and other men who have sex with men without documented history of travel to endemic countries, prompting many countries including the UK to roll out a vaccination programme.