People at risk of having caught monkeypox should isolate for three weeks, health officials in the UK have said.
The advice from the UK Health Security Agency (UKHSA) applies to those who have had direct or household contact with a confirmed case.
So far, there have been 20 confirmed cases of monkeypox in the UK. More than 90 cases have been identified across Europe, the US, Canada, Israel and Australia, and the World Health Organization (WHO) has warned of more to follow.
Monkeypox is often associated with travel to Central or West Africa, but some cases have occurred without a travel link.
The disease, first found in monkeys, can be transmitted from person to person through close physical contact, including sexual intercourse, and is caused by the monkeypox virus.
Is there a monkeypox vaccine?
In the UK, health officials are using a form of the smallpox vaccine, which is being given to the contacts of confirmed cases.
According to the government, the UK has in the past used the Ankara (Imvanex) vaccine, a third generation smallpox vaccine, for previous incidents of monkeypox.
What is monkeypox and how easily does it spread?
Ankara was approved in the US by its Food and Drug Administration (FDA) in September 2019. However, it has not been licensed in Europe or the UK.
On Sunday, Dr Susan Hopkins, chief medical adviser at UKHSA, said doctors are using a form of smallpox vaccine for those who have come into contact with cases.
She told BBC One’s Sunday Morning: “There is no direct vaccine for monkeypox but we are using a form of smallpox vaccine – a third-generation smallpox vaccine that’s safe in individuals who are contacts of cases.
“So, we’re not using it in the general population.
“We’re using it in individuals who we believe are at high risk of developing symptoms and using it early, particularly within four or five days of the case developing symptoms.
“For contacts, [this] reduces your risk of developing disease, so that’s how we’re focusing our vaccination efforts at this point.”
Last week, health secretary Sajid Javid said the government has some stocks of the smallpox vaccine and have procured further doses.
How effective is the vaccine?
The Centers for Disease Control and Prevention (CDC) in the US says that, based on past data from Africa, the smallpox vaccine is at least 85% effective in preventing monkeypox.
The CDC states: "Smallpox and monkeypox vaccines are effective at protecting people against monkeypox when given before exposure to monkeypox.
"Experts also believe that vaccination after a monkeypox exposure may help prevent the disease or make it less severe."
It recommends giving the vaccine within four days of the date of exposure to prevent onset of the disease.
If given between four and 14 days after the date of exposure, the vaccine may reduce the symptoms of disease, but may not prevent the disease.
How dangerous is monkeypox?
There have been reports of deaths from monkeypox in West and Central Africa since December.
However, the WHO says there have been no deaths in other countries where cases have been found.
The organisation said: "Since 13 May 2022, cases of monkeypox have been reported to WHO from 12 member states that are not endemic for monkeypox virus, across three WHO regions.
"The situation is evolving and WHO expects there will be more cases of monkeypox identified as surveillance expands in non-endemic countries. So far, there have been no deaths associated with this outbreak."
Monkeypox is not as easily transmitted as coronavirus, health experts say.
What are the symptoms of monkeypox?
According to the NHS, it can take between five and 21 days for the first symptoms of monkeypox to appear.
The first symptoms include a high temperature; a headache; muscle aches; backache; swollen glands; shivering or the chills, and exhaustion.
A rash usually appears one to five days after the first symptoms arrive. The rash often begins on the face then spreads to other parts of the body, most commonly the palms of the hands and soles of the feet.
The rash begins as raised spots, which turn into small blisters filled with fluid. These eventually form scabs which later fall off.
The symptoms usually clear up in two to four weeks.
Watch: UK government cautious but not 'concerned' about monkeypox outbreak