Mpox (monkeypox)

Mpox is endemic in tropical and rainforest areas of Central and West Africa, however since May 2022 there has been a large outbreak of mpox cases in non-endemic countries around the world, including Australia.

The experience internationally and in Australia to date is most cases have been among gay, bisexual and other men who have sex with men.

Person-to-person transmission of mpox occurs through very close contact with people that have the infection, such as skin-to skin contact during intimate or sexual contact. Mpox can also spread through respiratory droplets and contact contaminated materials or surfaces (such as contaminated clothing, towels or bedding).

Transmission occurs through:

• direct contact with infectious material from skin lesions of an infected person, including through broken skin (even if not visible), or mucous membranes (respiratory tract, conjunctiva, nose, mouth, or genitalia),
• respiratory droplets in prolonged face-to-face contact, or
• fomites, via contact with contaminated objects such as bedding or clothes. It remains unclear whether the virus can be transmitted through semen or vaginal fluids.

Aerosol-generating procedures are also a transmission risk.

Infectious period: People with mpox are infectious from the onset of symptoms (either prodrome or rash, whichever comes first), until the rash has scabbed over and the scabs have fallen off. This may take 2-4 weeks.

Mpox is a mild viral illness caused by infection with the mpox virus. It is usually a self-limiting illness with symptoms lasting for 2-4 weeks.

Incubation period is usually 7 to 14 days with a range of 5 to 21 days.

A person may have prodromal symptoms, which can include:

• fever or chills
• headache
• myalgia
• arthralgia
• back pain
• lymphadenopathy
• fatigue

A maculopapular rash is typical of mpox, and develops 1 to 5 days after initial symptoms, noting some people do not have prodromal symptoms. The rash often starts on the face and spreads to other parts of the body. The rash may be generalised or localised, discrete or confluent.

The rash usually evolves over 2-3 weeks, with progression of lesions classically occurring as follows:

• macules (lesions with a flat base),
• papules (slightly raised firm lesions)
• vesicles (lesions filled with clear fluid)
• pustules (lesions filled with yellowish fluid)
• lesions then scab over after 2-3 weeks, after which scabs fall off.

In the current outbreak, atypical presentations have been observed, for example, patients presenting with no or a mild prodrome, or a rash with few lesions or a single lesion only on the genital or peri-anal region. Some cases may present with proctitis (painful inflammation of the rectum) in the absence of an externally visible rash or lesion(s). 

Hospitalisation is uncommon, and usually occurs for pain management, secondary skin infections, or other complications. More severe complications of mpox infection can include cellulitis, pneumonia, sepsis, encephalitis and corneal infection.

All suspected cases of mpox should be tested for mpox virus. Notify the suspected case to Public Health via Public Health Units or the on-call Public Health Physician (08 9328 0553) by telephone if after-hours.

Appropriate personal protective equipment (PPE) (external site) should be worn while collecting samples from patients suspected to have mpox virus infection. This includes fluid repellent surgical mask, gloves, disposable fluid resistant long-sleeved gown, and eye protection (face shields or goggles).

Mpox is diagnosed by PCR testing. Specimens should be collected using a sterile dry swab by vigorously rubbing the base of the lesion, or a skin biopsy. Sample at least two lesions using individual swabs. Avoid using transport medium, as this may dilute the sample and increase risk of leakage Nasopharyngeal swabs are also suitable and should be collected. Specimens should be placed in two specimen bags (double-bag) to protect against leakage.

Information for people awaiting a test result can be found here (PDF 97KB).

Suspected cases should wear a mask, cover lesions where possible, and stay at home until a negative result is received.

Clinicians should consider the possibility of alternative diagnoses and test as appropriate, for example, syphilis, varicella zoster, herpes simplex, measles, molluscum contagiosum and bacterial skin infections.

Contact an Infectious Diseases Physician or Clinical Microbiologist for clinical advice if required.

All suspected and confirmed cases must be reported urgently by telephone to the Public Health Unit (see contact details at public health units). After hours, notify the on-call Public Health Physician by calling 08 9328 0553.

Notifications should be made using the Infectious Diseases notification form for metropolitan residents (PDF 214KB) or regional residents (PDF 213KB).

See Statutory medical notifications in Western Australia (Mpox virus infection) for further information.

Appropriate personal protective equipment (PPE) (external site) should be worn while collecting samples from patients suspected to have mpox virus infection. This includes fluid repellent surgical mask, gloves, disposable fluid resistant long-sleeved gown, and eye protection (face shields or goggles).

Other precautions should be taken to minimise exposure to surrounding persons and areas. In addition to staying at home until all lesions have crusted over, scabs have fallen off and a fresh layer of skin has formed underneath, people with suspected, probable, or confirmed mpox should:

• perform hand hygiene frequently
• wear a surgical mask if leaving their home for medical treatment, and
• cover any exposed skin lesions with non-stick dressings, a sheet or clothing/ gown.

When handling clothing and linen of suspected, probable, or confirmed cases, avoid shaking items or handling them in a manner that may disperse infectious particles into the environment.

Cleaning and disinfection advice:

Mpox virus will be inactivated through the use of a detergent followed by a Therapeutic Goods Administration (TGA) approved hospital-grade disinfectant with activity against viruses (according to the label and product information) or a bleach solution.

After and appointment or consultation with a person with suspected, probable, or confirmed mpox, the clinic room and fixtures and fittings, and equipment (or utilised area) should be thoroughly cleaned and disinfected.

• Remove PPE worn during the patient interaction and apply a new set of PPE before cleaning and disinfecting the room.
• Cleaning should be undertaken by cleaning with detergent, followed by cleaning with a TGA-list hospital-grade disinfectant with activity against viruses or a bleach solution. Some products combine a detergent and disinfectant in one.
• Do not reuse cloths, avoid dry dusting, sweeping, vacuuming, to prevent dispersal of infectious particles.
• Once surfaces are dry, the room can be safely used for the next patient consultation.

Refer to the Infection Prevention and Control Expert Group (ICEG) interim guidance on Mpox for health workers (external site) and the ICEG Interim guidance on the infection prevention and control of monkeypox at home or in a non-healthcare setting (external site) for further information.

Most people recover within a few weeks without any specific treatment. Antiviral medications can be prescribed in certain circumstances, on review by an Infectious Diseases Physician. Refer to the national Human Mpox treatment guidelines (external site) for more information.

If antivirals are indicated, the Infectious Diseases Physician should discuss accessing antiviral medication with their public health unit, or after hours via the on-call public health physician on 9328 0553.

Cases of mpox should stay at home until all lesions have crusted over, scabs have fallen off and a fresh layer of skin has formed underneath. Public Health will provide advice for cases about when they can leave home and resume normal activities.

Information for cases can be found on HealthyWA.

Vaccines are available for ordering now. Visit Mpox immunisation program for more information.

Public Health will initiate contact tracing for suspected and confirmed cases, as required. Contacts are classified based on risk of infection from their exposure to a mpox case. Contacts must monitor for symptoms for 21 days from exposure and follow public health advice provided by Public Health Units (see Mpox virus infection - CDNA National Guidelines for Public Health Units).

Vaccination may be offered as post-exposure prophylaxis for those at highest risk of becoming infected. Public Health will provide guidance regarding the use of the smallpox vaccination in mpox contacts.

Refer to your Public Health Unit for further advice.

• Mpox immunisation program
• WA Health webinars:
  • Mpox update for clinicians - 13 July 2022 (external site)
• Mpox chapter in Australian Immunisation Handbook(external site)
• Mpox Clinician Alerts – available at Health alerts – infectious diseases
• For consumer information: HealthyWA – Mpox (monkeypox)
• Australian Government Department of Health and Aged Care – Mpox (moneypox) (external site)
• ATAGI clinical guidance on vaccination against Monkeypox (external site)
• Mpox awareness campaign: Communications toolkit for stakeholders