Mpox (monkeypox) - including symptoms, treatment and prevention

Mpox (formerly known as monkeypox) disease is a rare disease caused by infection with the monkeypox virus.

Mpox is a notifiable condition¹

What is mpox?

Mpox is a viral infection that causes a rash.

The virus that causes mpox has historically had two distinct genetic clades, the Central African (Congo Basin) Clade I, and the West African Clade II.

In May 2022, a global outbreak of mpox Clade II began, with cases identified in many countries where the disease is not usually present including Australia.

In August 2024, the World Health Organization (WHO) declared an outbreak of mpox Clade I in parts of Sub-Saharan Africa as a Public Health Emergency of International Concern (PHEIC) after a significant increase in cases.

Clade Ia (which is circulating in parts of Africa) appears to be more severe and spread more easily than Clade II. Severity of Clade Ib is uncertain. Clade I has not been detected in Australia.

The mpox situation is changing rapidly.

How mpox is spread

Mpox is a zoonotic disease (spread to humans from animals). Spread from animals to humans occurs primarily in tropical rainforest areas of Central and West Africa, via contact with animals such as rodents or eating wild game. There is no evidence of spread from animals to humans in Australia.

Mpox is also transmitted from humans to humans, mainly through direct physical contact with infected body fluids, lesions or scabs on the skin, including through sex. It can also spread through prolonged contact with respiratory droplets (from coughing, sneezing, breathing and speaking) and contact with contaminated materials or objects, such as contaminated clothing, towels or linen.

A large proportion of cases in the 2022 global outbreak of mpox Clade II have affected men who have sex with men.

Signs and symptoms of mpox

Mpox infection usually causes symptoms including:

• fever
• headache
• muscle aches and backache
• swollen lymph nodes
• chills
• exhaustion
• rash.

1 to 3 days after the first symptoms occur, the person develops a rash, often beginning on one part of the body before spreading to other parts. The rash can vary from isolated lesions to several thousand lesions and goes through different stages.

The signs and symptoms in the 2022 outbreak have had some differences from the disease found in Central and West Africa including:

• the rash may be the first symptom that develops (prior to any other symptoms of illness)
• the rash may develop on the genital area first and may not spread to other areas
• the person may develop rectal pain and discharge (proctitis) as the first sign of local lesions developing.

Mpox will usually resolve in a few weeks.

Severe complications from mpox are more common in the very young, pregnant women and persons with impaired immune systems.

Image sourced from mpox: background information - GOV.UK (www.gov.uk)

Diagnosis of mpox

Anyone developing symptoms that may be consistent with mpox should seek medical care, covering any lesions, wearing a mask and calling ahead to make sure they can be isolated away from others.

Where a doctor suspects mpox based on the person’s symptoms, a swab of the rash will be taken to confirm the diagnosis by laboratory testing.

Incubation period

(time between becoming infected and developing symptoms)

Usually 1 to 2 weeks but can range from 5 to 21 days.

Infectious period

(time during which an infected person can infect others)

The person is considered infectious while they have symptoms and until all of the lesions have crusted, dried or fallen off and new skin has grown.

Treatment for mpox

As most cases of mpox are mild, medical treatment is not usually required. Treatment aims to reduce symptoms. Someone with mild mpox symptoms may only need simple pain medicines, such as paracetamol, and to stay hydrated.

If an infected person’s symptoms are more severe, they may need supportive management such as intravenous fluids and medicine to control fever or pain.

For people with compromised immune systems at greater risk of serious illness, treatments are currently under investigation.

Prevention of mpox

Infections with mpox virus can be prevented by the following measures:

• People with mpox should self-isolate away from other people and pets until all of their sores have healed and new skin has grown.
• People caring for or having contact with someone who has mpox hould wear personal protective equipment (PPE) including gloves and surgical mask.
• Practise good hand hygiene after contact with people with mpox. Wash your hands with soap and water or use an alcohol-based hand sanitiser.
• Avoid contact with any materials, such as bedding, that have been in contact with an infected person.
• As it is currently unclear whether viable virus may be present in semen after recovery, people who have had mpox should use condoms when having sex for 8 weeks after they come out of isolation.
• People who have sex while travelling or attend venues or events where intimate contact with a large number of people occurs should be aware of the risk of mpox. Although condoms are recommended, these are not fully protective as any skin-on-skin contact with an infected person poses a transmission risk.
• People travelling to countries in Central, East and West Africa where mpox is known to be present should avoid contact with sick animals (dead or alive) that could harbour mpox virus, including rodents and primates and should refrain from eating or handling wild game (bush meat).

Immunisation

Mpox is vaccine preventable.

Two doses of the mpox vaccine at least 28 days apart are needed for maximum protection.

The eligibility criteria to receive mpox vaccine in South Australia has been expanded.

People eligible to receive the vaccine include:

• Post-exposure preventive vaccination (PEPV) for close contacts of mpox cases
• Primary preventive vaccination (PPV) for:
  • all sexually active gay, bisexual or other men who have sex with men (including cis and trans men)
  • sexual partners of the people above
  • sex workers
  • laboratory personnel working with orthopoxviruses
  • health care workers at risk of exposure to mpox, who will be caring for patients in a Sub-Saharan African country where a mpox outbreak is occurring.
    

More information on mpox vaccine availability and how to book an appointment can be found on the SHINE SA and Adelaide Sexual Health Centre websites.  You may also access vaccine via your GP.

SA Health will continue to keep the South Australian community informed as both the epidemiological situation and availability of vaccines for mpox evolve.

1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.