Public health priority: Urgent.
PHU response time: Respond to any report of mpox disease on day of notification. Enter probable and confirmed cases on NCIMS within 1 working day. PHUs should also refer to the CDNA Monkeypox virus infection case and contact management guidelines if a suspected clade 1 case is notified.
This guidance has been adapted from the Communicable Diseases Network of Australia (CDNA) National Guidelines for Public Health Units, Monkeypox Virus Infection version 3 (SoNG) and is intended for the control of mpox due to Clade IIb.
The adapted guidance has been updated based on recent evidence of the risk of transmission and recognises that sex or other close, direct contact with lesions is the predominant mode of Clade IIb transmission. Although transmission by other mechanisms is theoretically possible, the updated guideline provides a proportionate response to balance risks in the context of the current Clade IIb outbreak.
Should a public health unit suspect a case of mpox may be due to Clade 1 Health Protection NSW CD-on call should be immediately contacted by telephone for further advice.
The NSW Control Guideline (this document) is approved for use in NSW but has not been endorsed by CDNA.
Mpox (formerly monkeypox) is a nationally notifiable disease.
Urgent: Respond to suspected, probable and confirmed cases immediately (within 24 hours).
Data entry timeline: Within 1 working day for all probable and confirmed cases.
Suspected cases should be notified to the public health unit (PHU).
When a suspected case has been identified, immediately (within 24 hours):
All probable and confirmed cases should be notified immediately to the public health unit.
When a probable or confirmed case has been identified, immediately (within 24 hours):
Refer to case management for further details on response times and procedures, treatment and exclusion and restriction guidance.
For contacts of probable and confirmed mpox cases:
Refer to contact management for information about public health measures recommended for medium and high-risk contacts.
Mpox is caused by infection with monkeypox virus. Monkeypox virus is an enveloped double-stranded deoxyribonumencleic acid (dsDNA) virus of the genus Orthopoxvirus (related to the Poxviridae family), which also includes variola virus (which causes smallpox), vaccinia virus (which is used to produce the smallpox vaccine) and cowpox virus (1).
Monkeypox virus has two distinct genetic clades. Clade one (I) is endemic in central Africa (Congo Basin) and typically causes more severe disease than clade two (II), which is endemic to west Africa (1, 2). Clade II consists of two subclades, Clade IIa and Clade IIb. Clade IIb refers primarily to the group of variants largely circulating in the global outbreak that commenced in 2022 (3).
The natural reservoir of monkeypox virus remains unknown. Monkeypox virus has been isolated from several African rodents and primates, including the Gambian pouched rat, tree squirrel, rope squirrel and sooty mangabey monkey, marking them as potential reservoirs for the virus (4, 5).
Following the eradication of smallpox in 1980 and subsequent cessation of smallpox vaccination programs, monkeypox virus has emerged as the most significant Orthopoxvirus for public health. Historically, mpox has primarily occurred in central and west Africa, often in proximity to tropical rainforests (1, 6).
Before 2018, the only cases with transmission outside Africa occurred in the United States of America, in a 2003 outbreak associated with imported rodents from Ghana that infected prairie dogs sold as pets (7, 8). Since early May 2022, monkeypox virus transmission has been reported in multiple countries outside Africa, including Australia. Cases notified since 20 May 2022 represent the first time the virus has been detected in Australia (9). The WHO declared the mpox outbreak a public health emergency of international concern on 23 July 2022. On 26 July 2022 (10), Australia's Chief Medical Officer declared mpox to be a Communicable Disease Incident of National Significance (CDINS) (11). On 25 November 2022 the national response to mpox was stood down and the declaration of mpox (formerly monkeypox) as a CDINS was rescinded. In the interim, mpox has continued to occur in many countries, primarily in men who have sex with men (MSM).
It has been suggested that the increasing case numbers and geographic spread of mpox in recent years may be related to decreasing population immunity due to cessation of smallpox vaccination programs and increasing urbanisation (12). Smallpox vaccination is protective against other Orthopoxviruses, including monkeypox virus (13, 14).
Transmission of monkeypox virus can occur when a person comes into contact with the virus from an infectious animal or human, or with materials contaminated with the virus (fomites) (15). Transmission occurs through broken skin (even if not visible), or mucous membranes (respiratory tract, conjunctiva, nose, mouth, or genitalia), and may occur though contact with infectious material from skin lesions of an infected person, through respiratory droplets in prolonged face-to-face contact, or through fomites. In the Clade IIb outbreak the highest risk of transmission is associated with direct and close contact particularly during sex (54-56).
Other potential routes of transmission are outlined below:
The incubation period is typically 7 to 14 days, with a range of 3 to 21 days (4, 26, 27)(57). The incubation period may be influenced by the route of transmission, with invasive exposure (e.g. contact with broken skin or mucous membrane) having a shorter incubation period than non-invasive exposure (28).
Cases may be infectious up to 4 days prior to the onset of symptoms, either prodrome, rash or proctitis. Cases remain infectious until the rash has resolved, and all lesions have formed scabs and fallen off, leaving fresh skin underneath. Some cases may not be aware of their exact symptom onset date as initial symptoms may be either very subtle and/or not visible (29-32).
Mpox is usually a self-limiting disease with symptoms lasting for 2 to 4 weeks.
The illness may have a prodromal period lasting 1 to 5 days that is characterised by lymphadenopathy, fever (≥38°C) or history of fever, headache, myalgia, arthralgia, back pain and sore throat (33). Not all cases report prodromal symptoms (33).
A maculopapular rash is typical of mpox and may develop 1 to 5 days after the onset of fever. The rash may be generalised or localised, discrete or confluent. It is classically described as centrifugal, more concentrated on the face and extremities than the trunk. Skin lesions often present at first as macules (lesions with a flat base), which progress to papules (slightly raised firm lesions), vesicles (lesions filled with clear fluid) and pustules (lesions filled with yellowish fluid). Crusted scabbing usually begins 14 to 21 days after rash onset. Scabs then fall off, leaving dyspigmented scars (34).
A typical distinguishing feature of mpox (Clade I and IIa), not observed in smallpox or varicella, is the presence of lymphadenopathy such as swelling at the maxillary, cervical or inguinal lymph nodes (35).
However, many cases in the current global outbreak of Clade IIb, have not presented with the classically described clinical picture for mpox (fever, swollen lymph nodes, followed by centrifugal rash) (24). Differing presentations of cases in the current Clade IIb outbreak have been described as follows1:
Symptomatic manifestations of mpox can cause severe pain and affect vulnerable anatomic sites; in particular painful proctitis or oral lesions may be the primary presentation. More severe complications of mpox infection include secondary infections including cellulitis, bronchopneumonia, sepsis, encephalitis and infection of the cornea with subsequent scarring and loss of vision. Severe dehydration may occur, secondary to vomiting, diarrhoea and oral lesions preventing adequate hydration (23).
1Proportion estimates of specific symptoms in Clade II outbreak cases presented above have been informed by a single study with a small sample size and should be considered accordingly.
Internationally, the mpox case fatality rate globally ranges from 0% to 11%, but there are challenges in accurately estimating this rate (36). In general, Clade II variants are considered to be milder than Clade I.
The Clade I variant has a case fatality rate (CFR) estimated at 10% (37), Clade IIa has an estimated CFR ranging between 1 and 6% (37, 38), and in the global Clade IIb outbreak which started in 2022 the CFR is estimated <0.1%.
For more information about global mpox case data, including deaths, please see: WHO Emergency situation reports.
In the context of the current outbreak, groups at increased risk of severe disease do not necessarily align with those at increased risk of acquiring mpox. Evidence on severe disease outcomes are limited but occur more frequently among people who are unvaccinated (30).
Immunocompromised individuals, including those with HIV infection that is not well-controlled (CD4 count <200 cells/µL), are at higher risk of severe disease (40-42).
Clade I outbreaks have recorded severe outcomes in children, especially children (younger than 10 years). This could be related to the cessation of smallpox vaccination, prolonged close contact with family members or caregivers who are cases and in endemic countries due to malnutrition and co-infections (43-46). Pregnant women and their foetus may also be at increased risk as vertical transmission has been recorded (21).
Anyone who is in very close contact with someone with mpox, particularly where skin-to-skin contact occurs, is at risk. While the mode of transmission means that anyone can acquire or transmit mpox, cases in the current outbreak have occurred primarily, but not exclusively, in gay, bisexual and other men who have sex with men (24, 33, 34, 47).
Cases have sometimes been associated with large events or parties (49).
High-risk settings and activities for transmission in the context of the current outbreak include:
Consideration of the following measures by PHUs may prevent transmission of the monkeypox virus and reduce mpox infections.
Individuals should also consider additional advice to minimise their risk of acquiring mpox:
During periods of local transmission PHUs should encourage active case finding:
Vaccines to prevent or reduce mpox infection and severity are available. Both post-exposure preventative vaccination (PEPV) and primary preventative vaccination (PPV) can reduce the likelihood of widespread community transmission.
Refer to the Australian Immunisation Handbook for specific vaccination information.
Key surveillance objectives are to:
Confirmed and probable cases should be entered on to Notifiable Conditions Information System (NCIMS), ideally within one working day of notification.
The date of onset is the date of symptom onset, which may be prodromal/systemic symptoms, rash, or proctitis.
Cases subsequently shown not to have mpox should be excluded within one working day.
Multi-jurisdictional outbreaks requiring national coordination may require support from the National Incident Centre (NIC).
For case definitions please see CDNA surveillance case definitions | Australian Government Department of Health and Aged Care.
Patients with symptoms who present with a history suggestive of exposure to mpox should have a specimen collected and be referred for laboratory testing.
Testing is performed at jurisdictional public health laboratories. General advice is outlined in the Public Health Laboratory Network Guidance on Monkeypox patient referral, specimen collection and test requesting for general practitioners and sexual health physicians. Specific advice from the medical microbiologist at the testing laboratory may be sought to obtain advice on specimen collection, safe packaging and transport.
Appropriate PPE should be worn when collecting samples from patients suspected of monkeypox virus infection per Clinical Excellence Commission Mpox (Monkeypox) Infection Prevention and Control Information for clinicians..
Lesion material should be collected from people with suspected monkeypox virus infection who have an active lesion or rash. Acceptable sample types include lesion fluid, lesion tissue, lesion crust or skin biopsy.
It is advisable to collect samples from more than one lesion where possible, however excessive sample collection should be discouraged to minimise risk to healthcare workers or laboratory personnel.
Patients presenting with proctitis or urethritis who have a history of potential mpox exposure, but no visible lesions should have an anal or urethral swab collected. During periods of local transmission of mpox all MSM presenting with proctitis should have an anal swab collected.
Throat or nasopharyngeal swabs may be collected in persons with prodromal symptoms who present with no lesions, e.g., a contact who develops symptoms.
Material should be collected using a sterile dry swab. Avoid using transport medium, as this may dilute the sample and increase risk of leakage. For further advice, including on appropriate PPE and safe handling and transport of specimens, refer to the Monkeypox Laboratory Case Definition..
Urgent: immediately (within 24 hours).
PHUs should begin follow-up investigation for all probable and confirmed cases on the day of notification to identify the source of exposure and contacts.
The response to a notification will often be carried out in collaboration with the case's treating clinician or local sexual health service. Regardless of who does the follow-up, for confirmed and probable cases of mpox.
PHU staff should ensure that action has been taken to:
Cases should be advised to do the following during their infectious period, including the prodromal and rash stages, and until advice has been provided by their managing clinician or PHU regarding clearance of infection.
Until they meet the clearance criteria, cases should:
Cases should avoid:
If lesions are unable to be covered, if a case has disseminated disease, or if there is likely to be generation of infectious droplets (e.g. mpox pharyngitis) then a case should be advised to isolate at home.
If the case has had recent travel to Africa, or there is another reason to suspect the case may have monkeypox virus Clade I, the case should be advised to isolate at home.
If cases work in high-risk settings and cannot work from home, PHUs may conduct a risk assessment on a case-by-case basis to ensure the case can safely attend the workplace. Factors to consider include: the type and nature of their work, number and location of their lesions, mode of transport to and from work. All lesions must be covered and the case should wear a surgical mask when in the high risk setting.
PHUs should ensure people with mpox have access to a PHU contact number to seek advice or support where required.
Cases should not donate any human tissue, including blood, cells, tissue, breast milk, semen, or organs for 12 weeks following clearance.
Cases can stop restrictions when all lesions have crusted, scabs have fallen off and a fresh layer of skin has formed underneath.
The managing clinician will advise on clearance of a case.
For 12 weeks following clearance, cases should:
For cases with non-visible skin lesions (e.g., cases with proctitis), it is recommended they follow the case exclusion and restriction requirements above until complete resolution of all symptoms.
International reports of asymptomatic monkeypox virus infection in the current global Clade IIb outbreak are rare and generally only detected and described in research studies. There is limited evidence available to determine whether asymptomatic cases are infectious.
Monkeypox virus infection is generally a self-limiting infection. Most cases will not require specific treatment other than supportive management or treatment of complications (e.g. antibiotics for secondary cellulitis).
Advice on clinical management should be sought from an infectious disease physician. If antiviral treatment is indicated, it should be initiated in consultation with an infectious disease physician and/or sexual health physician.
Tecovirimat (TPOXX) is the preferred treatment for severe monkeypox virus infection. Tecovirimat supply can be accessed through the NSW Specialist Service for High Consequence Infectious Diseases (HCID), 1800 4243 00 (HCID Physician on call).
For further advice, refer to the Australian Human Monkeypox Treatment Guidelines.
1Appropriate PPE as determined by the PHU based on a risk assessment including the nature of contact, likely transmission pathway/s and setting type, noting the minimum standard defined in the infection control section.
Direct follow of high-risk contacts by PHUs staff is the preferred mode of follow up.
Where it is not possible or preferred (by the case) for the details of contacts to be provided to PHUs, other strategies should be used to help ensure people at-risk receive public health information. The PHU could provide a written message for the case to pass on to people they think may be at risk. This may include:
Contacts of probable and confirmed mpox cases should monitor for signs and symptoms of mpox for 21 days after the date of their last exposure.
High and medium risk contacts should receive PEPV.
See Table 2 below for detailed guidance on management of high- and medium-risk contacts.
1Active self-monitoring is the contact watching for signs or symptoms compatible with mpox infection; if they appear, follow case exclusion and restriction criteria and seek medical review. If the contact is facing difficulty accessing medical review call the PHU for assistance.
During the incubation period the PHU may choose to regularly monitor high and medium risk contacts (by phone, email, text) to check for the emergence of any signs or symptoms at intervals if there are concerns about the contact's health literacy, self-efficacy, or if other supports are needed.
2For current ATAGI recommendations and the latest evidence for mpox vaccines, please see the ATAGI Interim Statement on the use of vaccines for prevention of mpox in 2024.
3Managing clinicians may choose to test asymptomatic high risk contacts based on an assessment of individual clinical risk. If an asymptomatic contact is eligible for PEPV, and the managing clinician elects to offer testing, awaiting the result of this test should not delay PEPV administration.
Mpox is spread by contact with lesions, body fluids and respiratory secretions, and contaminated materials. The extent to which transmission occurs via the respiratory route remains unclear. Refer to the latest guidance: Clinical Excellence Commission Mpox (Monkeypox) Infection Prevention and Control Information for clinicians.
In the event a case/s is reported to have attended an SOPV whilst infectious, or potentially acquired mpox at a SOPV, a PHU may consider the following outbreak management strategies:
Methods of messaging and the ability to contact trace may be limited due to the willingness of patrons to provide contact information. Best practice may require assessment on a case by case basis.
To minimise the risk of an outbreak occurring at an SOPV, venues are encouraged to implement the following preventative measures:
Congregate living settings are facilities or other housing where people who are not related reside in close proximity and share at least one common room (e.g. sleeping room, kitchen, bathroom, living room). Congregate living settings can include correctional and detention facilities, homeless shelters, group homes, dormitories at institutes of higher education, boarding schools, seasonal worker housing, residential substance use treatment facilities and other similar settings, but excludes healthcare settings.
In the event of a case/s in a congregate living setting, PHUs may consider the following outbreak management strategies:
If introduction of mpox occurs in an Aboriginal and Torres Strait Islander community, the risk of mpox transmission may be higher than the general community due to inadequate and overcrowded housing. For this reason, a low threshold should be used to initiate disease control measures, including consideration of communications and broader vaccination strategies. PHUs may consider targeted action to all community members in a remote Aboriginal or Torres Strait Islander community if supported by the epidemiological context. The nature of any action will depend on factors including the size and remoteness of the community. Community engagement should be central to any community-based response and should continue throughout implementation to ensure actions are culturally appropriate.
Workers in healthcare settings should always follow the Clinical Excellence Commission Mpox (Monkeypox) Infection Prevention and Control Information for clinicians when caring for a mpox case. If this guidance is followed appropriately, the risk of transmission between cases and contacts in a healthcare setting is minimal.
Case investigation form for mpox: fillable and non-fillable.