How Australia and Aotearoa New Zealand avoided large‐scale mpox (formerly monkeypox) outbreaks in 2022–2023

Abstract

In 2022, while the global community was recovering from the coronavirus disease 2019 (COVID-19) pandemic, a new global virus outbreak emerged, namely mpox. We describe how, despite significant challenges, Australia and Aotearoa New Zealand (AoNZ) managed to avoid large local outbreaks of mpox. Mpox virus was first identified in 1958 in laboratory monkeys in Denmark, hence its original name of monkeypox virus.1 In November 2022, the World Health Organization (WHO) announced it would adopt the term ‘mpox’, in recognition of the fact that monkeys are not its natural reservoir, and that the term ‘monkeypox’ could potentially contribute to forms of stigma, including racism and homophobia.2 Mpox virus is a zoonotic orthopoxvirus, related to variola virus (causes smallpox), and vaccinia virus (used in vaccines to immunise against smallpox). Subtypes of the mpox virus are classified as clades 1 and 2, the latter being further subdivided into clades 2a and 2b. Clade 1 is restricted to central Africa and causes more severe disease with greater mortality. The 2022 global outbreaks consisted of clade 2b cases. Previously reported case fatality rates vary by clade, from 1% to 6% for clade 2, to as high as 10% for clade 1 and up to 17% among children infected with clade 1.3 The first confirmed human cases of mpox were documented in 1970 in central Africa. In recent decades, several outbreaks have occurred in central and West Africa, likely because of waning population orthopox immunity since the cessation of smallpox vaccination in the 1970s, combined with population growth and urbanisation in areas inhabited by infected animals.4 Outbreaks on the African continent are thought to have started by zoonotic transmission from infected animals, with initially limited human-to-human transmission within households.4, 5 Surveillance of cases of mpox in African countries is lacking, so the true burden of disease is largely unknown. Between 2017 and 2022, a resurgence of mpox was seen with 558 cases (suspected and confirmed) reported in Nigeria, predominantly affecting young men.6 During this time, several isolated cases of mpox were reported in the United States, the United Kingdom and Singapore, all linked to travellers from Nigeria. While previously considered a zoonotic infection, these changes in mpox epidemiology support the hypothesis that sexual transmission between men was occurring in Africa prior to the 2022 global outbreaks.7, 8 The first case in the 2022 outbreaks in nonendemic countries was reported in the United Kingdom on 6 May 2022 by a patient who had recently travelled to Nigeria. This was soon followed by further patients who had not travelled to countries where mpox is endemic. Within the following weeks, additional cases were reported elsewhere in Europe, the Americas and Asia. Persons affected were predominantly (98%) gay, bisexual and other men who have sex with men (GBMSM),9, 10 and the international community eventually reached consensus that the primary mode of mpox transmission in the 2022 outbreaks was through sexual contact.11, 12 On 23 July 2022, the Director General of the WHO declared the outbreak to be a public health emergency of international concern (PHEIC),13 and by mid-August over 1000 cases were reported daily.14 On 11 May 2023, after almost a year, the WHO declared an end to the PHEIC. Over this period, more than 88 500 mpox cases had been reported globally, in 113 countries, with 150 confirmed fatalities equivalent to a case fatality rate of <0.2%.15 Also of note, almost 50% of cases seen in the 2022 global outbreaks were in people already known to be living with HIV.16 The clinical presentation of mpox varies by clade, but typically patients experience ‘prodromal’ symptoms with fevers, muscle pains, headaches and a sore throat, followed by painful skin lesions and lymphadenopathy. In previous outbreaks, patients presented with lesions numbering between 100 and 1000, covering their entire body, with 20–30% having genital lesions. These lesions typically evolved from macules, to papules, to pustules, before forming a scab. Healed lesions can leave a long-term scar. Mpox cases presented differently during the 2022 global outbreaks, with a shorter incubation period (up to 10 days rather than 21 days) and fewer mpox lesions, usually localised to the perioral, oropharyngeal and/or anogenital areas. These differences are thought to be due in part to differences in transmission routes, with transmission through inhalation of respiratory droplets being more common in previous outbreaks, and transmission through skin-to-skin contact during sex being more common in the 2022 outbreaks.3 A recent review by the US Centers for Disease Control and Prevention (CDC) suggests that transmission by the respiratory route is possible but was not the dominant mode of transmission during the 2022 outbreaks.17 Also, phylogenetic studies showed accelerated evolution of the virus in 2022.18 The phenotypic expression of these genetic changes is unknown but may possibly account for some of the observed differences in clinical presentation. Mpox complications, while uncommon, can include pneumonia, encephalitis, sepsis and secondary cellulitis.3 Several factors contributed to a high level of concern that the 2022 outbreaks might result in a large global epidemic. Globally, most people born after 1980 have not been vaccinated nor exposed to smallpox. Australia and AoNZ never had national vaccination programmes against smallpox, and instead conducted targeted vaccination campaigns during epidemics of smallpox, so population immunity is low, estimated at 10% of the population overall, and even lower for younger population groups.19, 20 Production of vaccinia vaccines was scaled back significantly following the global eradication of smallpox in 1980.21 As a result of safety concerns, earlier generations of vaccines (e.g. ACAM2000) were deemed unsuitable for broad population-level vaccination in response to mpox, and the much safer third-generation replication-deficient modified vaccinia Ankara (MVA-BN) vaccine was produced by a single vaccine manufacturer (Bavarian Nordic) with limited capacity to ramp up production. Furthermore, unlike ACAM2000, MVA-BN requires two doses at least 28 days apart to achieve optimal immunity, with programmatic implications. Some foreign governments kept stockpiles of MVA-BN for biosecurity purposes, some of which were made available to combat the 2022 mpox outbreaks. The mpox response was also hampered by a lack of antiviral medication. No antiviral treatments had been tested or licensed to treat mpox, but two treatment options could be used to manage more severe mpox infections: the antiviral tecovirimat and vaccinia immunoglobulin. AoNZ had some supply of tecovirimat (described below), but these treatments were in short supply in Australia. Other antivirals active against orthopoxviruses, such as brincidofovir and cidofovir, were essentially not available to treat mpox in Australia and AoNZ. In the context of an unvaccinated population, and scarce vaccine and antiviral medications, we witnessed rapidly evolving global outbreaks, with reported cases peaking in mid-August 2022 at just over 1000 cases daily, and a case doubling time of 7–10 days.14 The acceleration of the outbreak coincided with lesbian, gay, bisexual, transgender, intersex (LGBTI) Pride celebrations in the northern hemisphere. LGBTI Pride is a global phenomenon that celebrates diversity of sexuality and gender, usually held in the summer months, and numerous large gathering events were held across the United States, Canada and Europe, with an associated increase in sexual mixing. Domestically, Sydney was preparing to host World Pride in February and March 2023, potentially a mass transmission scenario. Given the situation abroad, states and territories mounted local public health responses engaging key clinical, laboratory and community networks and stakeholders in anticipation of cases of mpox being identified in Australia. The Australian Government acted swiftly, in partnership with states and territories, to secure supplies of MVA-BN vaccine. Due to high global demand and limited supply, the first deliveries of small numbers of vaccines were delayed until August 2022, with larger quantities arriving several months later. The first cases of mpox in Australia were diagnosed in mid-May 2022, in Victoria and New South Wales (NSW),22, 23 and case numbers remained in single digits until the end of June, when case numbers started to escalate. On 1 June 2022, the Communicable Diseases Network of Australia (CDNA) implemented its initial case definition for mpox, making it a notifiable infection, and on 28 July 2022, Australia's Chief Medical Officer declared mpox to be a Communicable Disease Incident of National Significance.24 By the end of 2022, 147 people had been diagnosed with mpox in Australia, affecting people across all states and territories, but mostly in Victoria and NSW. The majority of cases were GBMSM, and mostly acquired overseas. Except for small local outbreaks in Melbourne, there was little evidence of sustained local transmission in Australia. Early in the local outbreak, it was unclear whether mpox transmission was airborne or through droplets, skin-to-skin contact and/or fomites.17, 25 This initial evidence gap hampered the development of evidence-based recommendations for infection precautions for health care workers, contact tracing and risk reduction strategies for the affected community. On 27 July 2022, the CDNA published National Guidelines for Public Health Units to guide case definitions, diagnosis and management of cases and contacts.26 To ensure efficient communication at various levels of government across the country, the National Blood Borne Viruses and Sexually Transmissible Infections Standing Committee (BBVSS) established an mpox subcommittee, which met weekly during the outbreak, with representatives from each of the federal, state and territory health departments, and from peak organisations representing affected communities and clinicians, including representation from state-based AIDS Councils and the National Aboriginal Community Controlled Health Organisation (NACCHO).27 This committee played a critical role in providing updates on global, national and local cases, the rollout of health promotion initiatives, and preparing for vaccine delivery. At a local level, mpox vaccination hubs were created, some of which were created anew, while others were repurposed COVID-19 vaccination hubs. Vaccinations were free for anyone at risk of mpox, regardless of residency status. Dedicated vaccination sessions were organised at some hubs in partnership with relevant local community-based organisations, to promote uptake by populations that might otherwise miss out, such as sex workers with GBMSM clients, trans and sex-diverse communities, and Aboriginal and Torres Strait Islander communities. Additionally, vaccines were delivered through LGBTI general practices and public sexual health clinics. Given the initially limited supply of MVA-BN vaccines, temporary strategies to maximise vaccine coverage for the at-risk community included providing a single vaccine dose and delaying the second dose until larger supplies became available, and utilising intradermal administration of MVA-BN rather than standard subcutaneous administration. Intradermal administration requires one-fifth of the subcutaneous dose (0.2 mL intradermal vs 1.0 mL subcutaneous of MVA-BN); hence, one single-dose vial could be used to immunise five people. This created additional challenges, as staff required training in intradermal vaccination techniques. By the start of Sydney World Pride, over 30 000 doses of MVA-BN vaccine had been provided to the at-risk community in NSW (personal communication, P. Read). Clinical assessment and testing for mpox was free through publicly funded sexual health clinics. Initial laboratory testing utilised panorthopox polymerase chain reaction assays in public hospital laboratories, which were subsequently replaced by mpox-specific assays. People diagnosed with mpox were followed up by local public health units, to manage case isolation and contact tracing. Crucially, the mpox response leveraged existing infrastructure and partnerships created in response to the HIV epidemic. This included the creation of the National Mpox Taskforce (Table 1), co-chaired by Health Equity Matters (HEM) and the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM), with representation from NACCHO, to ensure a nationally consistent approach to communication with the professional workforce and community organisations, and in reporting back to government. The National Mpox Taskforce immediately addressed two complexities: First, to develop a common narrative by which communities and clinicians could communicate about mpox using nonstigmatising language. Second, to avoid excessively restrictive public health policies, which could inadvertently create barriers to health care engagement. ASHM developed education for health care professionals, including webinars attended by 703 live participants and 1340 views of recordings, and updated the Australian STI Management Guidelines to include a new chapter on mpox.28 The Australian Government delivered education and updates available to all general practitioners (GPs) and other primary care providers, including workers from Aboriginal Community Controlled Health Organisations, recognising that people with mpox symptoms could present to any clinical service. As an outbreak that was concentrated among GBMSM, Australia's community-led HIV organisations mobilised rapidly, utilising expertise of working with GBMSM to address HIV. HEM, Australia's national community-led organisation, worked with research and clinical partners to translate emerging mpox knowledge into resources for policy development, political advocacy and health promotion campaigns delivered by its member organisations, which are Australia's state and territory AIDS Councils. The National Mpox Taskforce established a community subcommittee, comprised of the CEOs of HEM's member organisations, to consult with community-controlled LGBTIQ health care providers, and to provide rapid updates to community leaders on emerging mpox knowledge. Equally important, the subcommittee canvassed observational data from community leaders to inform briefings to the national mpox subcommittee of the BBVSS Committee and to the Australian Minister for Health and Aged Care. Another aspect of HEM's work, and that of its member organisations, was to inform the community about mpox through health promotion and education, adapting websites and social media channels established for their HIV work to include materials on mpox in multiple languages (see ‘Mpox Resources’ below). Also, HEM and its members delivered regular webinars on mpox for the blood borne virus (BBV) and sexually transmissible infection (STI) community workforce and for community members in general. Lessons from the HIV response have illustrated how stigma deters key populations from engaging with health services. Placing community organisations in command of developing public messages ensured that communications in Australia were nonstigmatising and nonjudgemental, and therefore effective. With the exception of one egregious media incident,29 Australia navigated mpox without harmful narratives or stigmatising language taking hold in the general community. Following the global outbreak, mpox was made notifiable in AoNZ in June 2022, which also meant that testing and treatment for mpox were made available free of charge in all settings (GP practices, sexual health clinics, or after-hours urgent care clinics) regardless of the patient's citizenship, residency or immigration status. The first case of mpox in AoNZ was diagnosed in early July 2022. As of 16 June 2023, 41 cases were reported, of which 10 were acquired overseas and 31 were identified as community transmission, the last being diagnosed on 12 January 2023. Reportedly, 36 of 41 cases occurred in GBMSM.30 The antiviral tecovirimat was imported into AoNZ and made available as a hospital-only medicine from August 2022. Data regarding its uptake are not available. The MVA-BN vaccine was imported into AoNZ in late December 2022. It has the status of "unapproved medication or vaccine" (Schedule 29 of the Medicines Act), and therefore cannot be advertised or promoted to at-risk individuals and communities by health professionals or nongovernmental organisations (NGOs). Its administration requires a face-to-face consultation with a medical doctor (other vaccinators, such as nurses or pharmacists, are not approved to administer it) with a detailed process of written for each 16 January 2023, consultation cannot be vaccination because of the were made available in across AoNZ for people who might be at high risk for mpox. The community response in AoNZ was by the the AIDS and the Health within the by This included several could not be at the with 500 people each The for for men to be in the outbreak response from the The government response in AoNZ included as or working by of or other public included representation at and clinical of mpox vaccination has been vaccination numbers are not available, but that 10% of the population has been The vaccine uptake is likely the result of delayed vaccine after the peak of the outbreak, combined with the by This AoNZ to a resurgence of mpox. initial in supply of vaccine Australia and AoNZ mpox outbreaks. This is most likely because of the rapid public health which in high levels of of mpox and its clinical among the affected community and clinicians, to rapid and early case isolation and contact tracing by public health This rapid response was made possible through between the clinical public health and laboratory the community to ensure that the entire mpox response was for the GBMSM community and In the GBMSM being to the mpox outbreak by sexual practices, which is likely to have had a significant on transmission This subsequently rapid of mpox vaccines when these became available in Australia, and in an estimated of at most risk had at least one with of two doses (personal communication, P. Read). This with other for data from the United that of GBMSM at least one vaccine uptake likely contributed to the of an mpox outbreak during World Pride in Sydney in March 2023. the most over from Australia's HIV is the to with the affected community through organisations to ensure that outbreak responses are and to avoid the of stigma and its on health care including these some people with mpox reported stigma and while engaging with health the for greater of how to stigma in health with the community was also key to in public health so that case contact tracing and could be implemented most and to ensure that the initially scarce vaccine supply was delivered to people at risk of mpox, while the of the GBMSM community for larger supplies to available, despite high levels of Another aspect of the mpox response was the rapid and of between various levels of government and the clinical and research by utilising developed during the HIV These included public sexual health clinics, community organisations such as HEM and its member organisations, and clinical support such as The GBMSM community is the first to be affected by emerging and these to rapidly to outbreaks is likely to also the general taking a to avoid global mpox outbreaks, countries with fewer resources be in their mpox Surveillance data are but the Africa reported confirmed cases and fatality rate of mpox in 2022, across African these outbreaks, African have supply of Mpox transmission among GBMSM in Africa has been and this the of sexuality related stigma in affected which is a likely to health care Australia and AoNZ have a to support mpox and in including New where of and is a part of each to this Health The the communities of gay, bisexual and other men who have sex with men in Australia, AoNZ and globally, who practices in communities of care to address an emerging The also Aboriginal and Torres Strait Islander as the of the where we live and work and across Australia. The and to and The the of and and expertise of Aboriginal and Torres Strait Islander and communities in communities The support the Aotearoa on the STI and between and in

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