The World Health Organization (WHO) has urged men who have sex with men to have fewer sexual partners to stop the spread of monkeypox.
The health body has forecast there will be just over 27,000 cases of the virus in 88 countries by next Tuesday, up from 17,800 cases in nearly 70 countries on the same day this week.
In total, five deaths from the virus have been reported globally and 10% of cases have been admitted to hospital, with the WHO declaring the outbreak a global emergency.
The majority of infections seen so far have been in men who have sex with men.
Watch: Monkeypox: WHO declares global health emergency over 'extraordinary' outbreak
WHO director-general Dr Tedros Adhanom Ghebreyesus said: "This is an outbreak that can be stopped, if countries, communities and individuals inform themselves, take the risks seriously, and take the steps needed to stop transmission and protect vulnerable groups
"The best way to do that is to reduce the risk of exposure. That means making safe choices for yourself and others.
"For men who have sex with men, this includes, for the moment, reducing your number of sexual partners, reconsidering sex with new partners, and exchanging contact details with any new partners to enable follow-up if needed."
But he stressed there must be no stigma or discrimination against any groups as this could be as “dangerous as any virus”.
Sexual intercourse is thought to expose people to a higher risk of contracting the disease as, although it is not known to be sexually transmitted, the close physical contact involved means exposure is more likely.
The most likely route of monkeypox transmission is close physical contact, touching clothing, bedding or towels used by someone with the monkeypox rash, or touching monkeypox skin blisters or scabs.
There is a smaller risk of it spreading through coughs and sneezes, and as prolonged face-to-face contact would be needed, this is not one of the main transmission routes for the monkeypox virus.
Sexual health organisations recently estimated that could be about 125,000 people in the UK with monkeypox.
Jimmy Whitworth, a professor at the London School of Hygiene and Tropical Medicine, said he expected that cases would not plateau for at least the next four-to-six months, or until those at highest risk of infection have been vaccinated or infected.
In the UK, men who have sex with men are being prioritised for the vaccine.
Currently, more than 18 clinics are vaccinating people in London, which has seen the highest cases.
On Tuesday, Ireland announced the monkeypox vaccine would be prioritised for men who have sex with men and other people at high risk of unprotected exposure.
It followed recommendations made last week by the National Immunisation Advisory Committee (NIAC) to the interim chief medical officer (CMO) who endorsed them