Mpox cases on the rise

What is the issue?

Mpox is an infection caused by the monkeypox virus. Monkeypox virus has two distinct genetic clades. Clade one (I) is endemic in central Africa and typically causes more severe disease than clade two (II), which is endemic to west Africa.

A subclade known as Clade IIb, has been largely circulating since 2022 in the global mpox outbreak, mostly impacting gay, bisexual, and other men who have sex with men (GBMSM).

As of 21 August, 120 mpox cases have been notified in Victoria since April 2024. All infections reported in Victoria to date have been caused by Clade IIb. Up to date Victorian mpox case numbers are available in the public-facing Notifiable conditions report. Data are updated daily.

On 14 August 2024, the World Health Organization declared the mpox outbreak in central and eastern Africa a Public Health Emergency of International concern in the context of an emergent mpox strain, Clade Ib, which is likely to cause more severe disease, and its rapid spread throughout the Democratic Republic of Congo and neighbouring countries.

Clade Ib has not been detected in Australia to date.

Who is at risk?

In Victoria, GBMSM are most at risk in the current outbreak. Anyone who has been in close and usually prolonged intimate contact with someone with mpox is at risk.

Symptoms and transmission

Mpox is a viral infection that usually results in a mild illness. Most people recover within a few weeks. However, some people may develop severe illness and require hospitalisation.

Symptoms can occur up to 21 days after being exposed to mpox.

Symptoms may include fever, chills, tiredness, headache, sore throat, muscle aches, swollen lymph nodes and rash. The rash can appear as vesicles, pustules or ulcers and affect any part of the body, including the anogenital area. Other symptoms may include pain on urination (urethritis) or rectal pain, bloody stools and/or diarrhoea (proctitis).

Infection can still occur in vaccinated people, but symptoms may be less severe. Atypical or attenuated clinical presentations can occur particularly in fully or partially vaccinated individuals.

Mpox can spread from person-to-person through close or prolonged skin-to-skin contact, for example during sexual contact, as well as contact with contaminated items or surfaces, and respiratory droplets.

People may be infectious up to four days before the onset of symptoms, either prodrome, rash or proctitis. People remain infectious until the rash has resolved, and all lesions have formed scabs and fallen off, leaving a fresh layer of skin underneath.

Recommendations

For people at increased risk of mpox

• If you have symptoms of mpox, restrict contact with others and seek urgent medical care and testing from your GP or local sexual health clinic. Make sure to wear a mask, cover any exposed rash lesions and call ahead.
• Get vaccinated if you meet the eligibility criteria to receive the free mpox vaccine.
• Two doses of mpox are required for optimal protection against transmission and severe disease. If you have not had your second dose, get it now.
• No vaccine is 100 per cent effective and mpox may occur in vaccinated people.
• Consider limiting the number of your sexual partners during the current outbreak and ensure that you have their contact details so that if a partner develops mpox you can be contacted and offered vaccination (post-exposure prophylaxis).
• For more information on measures to prevent the spread of mpox, see the Better Health Channel mpox webpage.

For clinicians

• Clinicians should test for mpox in all patients presenting with compatible symptoms, particularly among GBMSM (including those who may identify as heterosexual), and those with an international travel history.
• Symptoms may include vesicular or pustular rashes anywhere on the body, anogenital lesions or proctitis (anorectal pain with or without anal lesions). Consider testing for mpox in anyone who is at risk presenting with symptoms compatible with a sexually transmitted infection.
• Case reports of atypical and attenuated presentations in fully and partially vaccinated people are increasing, and clinicians should be alert to this possibility, particularly in those with risk factors.
• Request mpox PCR on suitable samples such as swabs of rash lesion material (fluid or base of lesion), including anorectal swabs for patients presenting with proctitis and pharyngeal swabs. Mark samples as “urgent” and send to the Victorian Infectious Diseases Reference Laboratory (VIDRL) via your routine pathology provider. Clinicians should wear appropriate personal protective equipment (PPE) when collecting samples.
• Any suspected or confirmed mpox cases should be urgently notified to the Department of Health by calling 1300 651 160.
• Review the mpox vaccination status of all eligible patients. Offer mpox vaccination to those who are unvaccinated and offer the second dose if they are due or overdue. Providers are encouraged to record mpox vaccinations to the Australian Immunisation Register (AIR).
• Mpox vaccine can be administered via the subcutaneous route and is readily available to immunisation providers through Onelink online.

For more information, including mpox vaccination, see the Department of Health mpox webpage.

Mpox vaccine eligibility

Eligibility criteria for free mpox vaccination were updated in May 2024. Primary prevention vaccination (PPV) and post-exposure preventative vaccination (PEPV) eligibility criteria have been expanded to include additional at-risk groups.

In Victoria, the mpox vaccine (JYNNEOS®) is available free-of-charge for eligible people who meet any of the following criteria:

Post-exposure preventative vaccination (PEPV) preferably in 4 days, in accordance with clinical guidance from the Australian Technical Advisory Group on Immunisation (ATAGI) for:

• High-risk contacts of mpox cases.
• Attendees of Sex-on-premises venues and public or private events (particularly where sexual or intimate contact has occurred) in areas where local transmission of mpox is occurring.

Eligible people for primary preventative vaccination (PPV) include:

• Sexually active gay, bisexual, or other men who have sex with men.
• Sexually active transgender and gender diverse people, if at risk of mpox exposure.
• Sex workers, particularly those whose clients are at risk of mpox exposure.
• Sexual partners (including anonymous or intimate contacts) of the above groups.
• Sex-on-premises venue staff and attendees.
• People living with HIV, if at risk of mpox exposure, and their partners.
• Laboratory personnel working with orthopoxviruses.
• Vaccination may also be considered for healthcare workers at risk of exposure to patients with mpox, based on local risk assessments. This may include primary care, sexual health clinics, hospital staff and others. The risk of transmission should also be minimised by using infection control measures.

See mpox disease information and advice for more information.

Currently, ATAGI does not recommend booster doses of the mpox vaccine for people fully vaccinated with two doses, including those who are severely immunocompromised.

Mpox vaccination is not currently recommended as a travel vaccination, unless people are otherwise eligible for mpox vaccination in Victoria.

For the most up to date travel information, visit Smartraveller.

How to access vaccines

Mpox vaccines are widely available through sexual health clinics, hospitals, general practitioners, Aboriginal health services, councils and community pharmacies. Eligible people can search for a local mpox immunisation provider in their local government area on the Better Health Channel or contact the following sexual health clinics:

• Melbourne Sexual Health Centre
• Thorne Harbour Health
• Northside Clinic
• Collins Street Medical Centre
• Prahran Market Clinic
• Sexual Health Victoria

Alternatively, people can contact their Local Public Health Unit (LPHU) for further information or assistance with locating their local mpox immunisation provider.

Clinics may not always be able to accept new patients. Please note while the vaccine is free, the consultation may not be. Speak to your immunisation provider to verify consultation-related fees and vaccine availability.