High risk contacts of monkeypox patients are required to isolate for three weeks, guidance from UK health chiefs states.
Others who had a lesser degree of exposure are advised to steer clear of children, people with conditions affecting their immune systems and pregnant women - but are not required to stay home.
Guidelines introduced in 2018 state that everyone identified as a contact is assessed on a "case by case" basis in order to contain the disease.
Those identified as being at risk are divided into three categories, with those in the highest level ordered to quarantine for 21 days.
The rules were brought in following cases of monkeypox in 2018, and have not been changed in light of the latest outbreak.
Scroll down to see the guidance for each category of contact
The UK has confirmed 20 cases of monkeypox in the past fortnight - having previously recorded just seven cases since the virus was first discovered in humans in 1970.
Yesterday the World Health Organisation said there were 92 confirmed cases and 28 suspected cases in 12 countries where monkeypox is not endemic.
The UK Health Security Agency (UKHSA) said that those who come into contact with a monkeypox case are given advice based on their level of exposure.
A UKHSA spokesperson said: "The maximum isolation period for the highest category of contact is 21 days from the point they interacted with someone with monkeypox.
"However, isolation advice is given on a case-by-case basis depending on the specific exposure circumstances of that individual so will differ among different contacts."
Level three - High risk
These are people who have unprotected direct contact or high risk contact with those with monkeypox.
For people in this situation, health chiefs advise:
- Self-isolation for 21 days, including exclusion from work
- No travel permitted
- Avoid contact with immunosuppressed people, pregnant women, and children aged under 12 where possible
The document states that those who fall into this contact are most likely to have had "household contact" and "sexual contact" with the person with monkeypox.
They are likely to have direct exposure to a patient's broken skin, bodily fluid or items such as clothing or bedding without wearing PPE.
Level two - Medium risk
These are people who have not had contact with broken skin or sores, but may still have had physical contact or who could have contracted the virus through droplets.
They include those who have touched with unbroken skin or have been within a metre of someone with monkeypox - such as a person directly next to them on a plane.
While they are not required to isolate, health protection teams are required to make daily contact for 21 days after exposure to check if they are showing any symptoms.
They are advised not to come into contact with immunocompromised people, pregnant women and children under 12.
The guidelines state that they can be excluded from work for three weeks if their job requires contact with anyone who falls into these categories.
Level one - low risk
This group includes people who have had close contact with monkeypox patients while wearing PPE, or those who have been within one and three metres of a case.
These includes people sitting within three rows from an infected person on a plane.
They are not required to live under any restrictions, but are told to contact their local health protection team if they display any symptoms.
What are experts saying?
Dr Susan Hopkins, a chief medical adviser of the UK Health Security Agency (UKHSA), said there is "absolutely" community transmission of monkeypox in the UK.
She also said cases have been predominantly confirmed in individuals who self-identify as gay or bisexual.
Speaking to BBC One's Sunday Morning, she said: "Absolutely, we are finding cases that have no identified contact with an individual from west Africa, which is what we've seen previously in this country.
"The community transmission is largely centred in urban areas and we are predominantly seeing it in individuals who self-identify as gay or bisexual, or other men who have sex with men."
Asked why it is being found in that demographic, she said: "That's because of the frequent close contacts they may have.
"We would recommend to anyone who's having changes in sex partners regularly or having close contact with individuals that they don't know to come forward if they develop a rash."
How is monkeypox spread?
Experts say monkeypox does not spread easily between people.
The UKHSA says: "Spread of monkeypox may occur when a person comes into close contact with an infected animal (rodents are believed to be the primary animal reservoir for transmission to humans), human, or materials contaminated with the virus. Monkeypox has not been detected in animals in the UK.
"The virus enters the body through broken skin (even if not visible), the respiratory tract, or the mucous membranes (eyes, nose, or mouth)."
It said that the main means of person-to-person spread are:
- contact with clothing or linens (such as bedding or towels) used by an infected person
- direct contact with monkeypox skin lesions or scabs
- coughing or sneezing of an individual with a monkeypox rash
What are the symptoms?
Those who become ill usually make a full recovery within four weeks, health officials believe.
But the virus can be deadly, and is believed to have a fatality rate of around one per cent.
First signs of infection include:
- fever
- headache
- muscle aches
- backache
- swollen lymph nodes
- chills
- exhaustion
A rash usually develops within five days, often starting on the face then spreading across the body.
These marks usually turn to scabs, which eventually fall off.
UKHSA says: "An individual is contagious until all the scabs have fallen off and there is intact skin underneath. The scabs may also contain infectious virus material."
