mpox

• Monkeypox virus, an enveloped double-stranded DNA virus of the genus Orthopoxvirus.

Special considerations

Complications are more common in people who are immunocompromised, such as people living with HIV with a CD4 count < 200 cells/uL.

NAAT – Nucleic acid amplification test

Specimen collection guidance: Clinician collected | Self-collection

• Contact your local laboratory prior to specimen collection to check the availability of mpox tests (NAAT). Alternatively, contact your nearest hospital laboratory to arrange transport of specimen(s).
• Dry swab transport tubes are the preferred option to avoid the risk of leakage during transport and allows for laboratory staff to process the specimen appropriately. However, if swabs in VTM or liquid Amies is being used please ensure the lid is appropriately secured. Use of bacterial culture swabs (e.g. containing gel media for bacterial preservation) is not acceptable to perform NAAT testing.
• Where there are distinct anatomical or morphological lesions consider swabbing at least 2 lesions with separate swabs, and write the lesion site on the specimen containers.
• If no lesion fluid is available for collection, then dry crusts or biopsy material can be tested; to be transported in a dry container.
• Wear adequate PPE, including gown, gloves, surgical mask, and eye protection.
• Avoid contact with contaminated materials (e.g., bedding).

Investigations 

• Public laboratories have implemented mpox-specific PCR/NAAT assays.
• Some laboratories may still use Orthopox PCR/NAAT assays instead.
• Some commercial laboratories do not have a specific assay.

Clinical indicators for testing

• Testing is only indicated when patients present with symptoms suspected of being due to mpox virus.
• Asymptomatic screening, or testing asymptomatic contacts for mpox is not recommended, as asymptomatic carriage appears rare.

Special considerations

• Swab suspected mpox lesions for HSV PCR, syphilis PCR, and LGV PCR, as these are important differential diagnoses.
• Consider swabbing suspected mpox lesions for M/C/S, as secondary bacterial cellulitis is common.
• Perform full HIV/STI screen at time of presentation, as co-infection with HIV/STIs is common.

Treatment advice

• Most cases are mild and self-limited, and do not require specific antiviral therapy.
• Patients who may require antiviral therapy should be discussed with an infectious diseases physician or sexual health physician. Indications for urgent discussion with a specialist include: (1) severe mpox disease (e.g. sepsis, encephalitis, eye infection); (2) one or more complications (e.g. secondary cellulitis, dehydration, pneumonia); or (3) those at risk of severe disease (e.g. immunocompromise such as CD4 count < 200 cells/uL, children, pregnancy, breastfeeding). See Australian Mpox Treatment Guidelines for more detail.
• Tecovirimat was made available through the National Medical Stockpile based on in vitro data however two subsequent randomised controlled trials did not demonstrate clinical benefit. Nonetheless people at significantly increased risk of severe disease should be discussed with an export as treatment may still be advised for some people. Common adverse effects of tecovirimat include headache, nausea, abdominal pain and vomiting, but it otherwise appears safe.
• Vaccinia immunoglobulin (VIG) is held in the National Medical Stockpile in limited quantities. For toxicity, precautions and contraindications, see the Australian Mpox Treatment Guidelines.
• Patients who need to be admitted to hospital should be discussed with the receiving infectious diseases team prior to transport to hospital, to ensure that appropriate biocontainment strategies can be enacted.
• Consider early initiation of empiric antibiotics if secondary cellulitis is suspected.
• Consider strong analgesia for mpox lesions in troublesome areas such as the oropharynx and anorectum.
• Painful lesions may benefit from topical lignocaine.
• Anal lesions may benefit from stool softeners.
• Best-practice wound care for mpox lesions is important to reduce the risk of cellulitis.

For more information, see the Australian Mpox Treatment Guidelines.

Other immediate management

• The risk of occupational transmission is minimal if healthcare workers follow the ICEG interim guidance on mpox
• Upon clinical suspicion of mpox, immediately phone the local public health unit for advice on exclusions and restrictions during their infectious period before the patient leaves the clinic. See CDNA National Guidelines for Public Health Units on Mpox.
• Cases are considered infectious until scabs have fallen off and a fresh layer of skin has formed.
• Cases with anal pain/bleeding are considered infectious until their anal symptoms have completely resolved.
• Mpox viral DNA has been found in the semen of men who have recovered from clinical mpox disease. This raises the possibility that mpox could be transmitted via semen for some weeks following clinical infection. However, to date there have been no definitive mpox transmissions via semen from someone who has recently recovered from mpox. For this reason, people who have a penis and who have recently recovered from mpox may wish to use condoms for some time after recovery from their mpox infection to reduce the risk of transmission to sexual partners who have not been vaccinated or previously infected.
• Immunocompromised people are at higher risk of complications of mpox infection. Closely monitor PLHIV with a CD4 count < 200 cells/uL, or with an AIDS diagnosis in the preceding six months, or with persistent HIV viraemia (HIV VL > 200 copies/mL). For a full list of relevant immunocompromising conditions, see the Australian Mpox Treatment Guidelines.
• Pets are at risk of infection and this risk should be considered during isolation, and may need to be re-housed temporarily to avoid the risk of mpox transmission to the pet.

Special considerations

• Consider seeking specialist advice before treating any complicated presentation.

• Seek immediate local Public Health Unit assistance with contact tracing.
• Contacts are stratified as low-risk, medium-risk, or high-risk, as described in the CDNA National Guidelines for Public Health Units on Mpox.
• Medium and high-risk contacts should be offered post-exposure vaccination with a subcutaneous dose of 3^rd-generation vaccinia vaccine (i.e., MVA), ideally within 4 days of last contact, but up to 14 days of last contact. Post-exposure vaccination more than 4 days after last contact may not prevent infection, but it may attenuate disease severity.
• Contacts who receive post-exposure vaccination should receive a subcutaneous vaccine dose at least 28 days after their initial subcutaneous dose, unless they develop mpox infection in the interim.
• For isolation and post-exposure vaccination advice for contacts, see CDNA National Guidelines for Public Health Units on Mpox.

• Depending on clinical severity, arrange regular clinical reviews by telehealth while the patient is isolating to assess progress of recovery, emergence of complications, and need for assistance with isolation.
• Patients with laboratory-confirmed mpox infection are considered to be immune from re-infection, at least in the short to medium term after recovery, and hence do not need immunisation.

Test of Cure (TOC)

• TOC is not necessary, as this is a self-limiting infection.

Test for re-infection

• Re-testing for mpox is not necessary.

Special considerations

• Offer HIV pre-exposure prophylaxis to anyone who has recovered from mpox, after conducting appropriate assessment. See PrEP Guidelines.

• All cases of mpox are immediately discussed with the local Public Health Unit.

• ASHM’s mpox Resource Toolkit
• ASHM’s mpox vaccination training (online learning module)
• Australian Human Monkeypox Treatment Guidelines
• CDNA National Guidelines for Public Health Units on Monkeypox Virus Infection