Infectious disease experts share the latest on monkeypox

News | Published on 01 Sep 2022

Infectious disease experts have said that control of current monkeypox outbreaks is needed, that people should be vigilant of monkeypox symptoms, and take heed of lessons learnt from past epidemics, in an online webinar hosted by the Kirby Institute at UNSW Sydney last week.

The Kirby Institute’s Professor Raina MacIntyre and Professor Andrew Grulich, and Deputy CEO of AFAO, Heath Paynter, gave an in-depth overview of the current monkeypox epidemic, including how it emerged, the current research on transmission and vaccination, and considerations that should be taken in approaching control of the virus.

The evolution of monkeypox

Prof MacIntyre, who is a smallpox expert and head of the Kirby Institute’s Biosecurity Program, explained the relationship between monkeypox and smallpox; both orthopox viruses which have existed for hundreds of years. The eradication of smallpox in 1980, she explained, was thanks to mass vaccination globally. Due to the relationship between the two viruses, the global stockpile of smallpox vaccine is being utilised against monkeypox; but supply is limited, so administration of the vaccine will need to be carefully considered. More importantly, the world needs to move quickly to contain the current outbreak. “We’re concerned about spread to children and immunosuppressed. We don’t want it getting established in animal hosts in Australia because then we’ll be living with it forever,” she said.

Also concerning are signs of genetic mutation in humans. “It could keep changing unless we can control it really aggressively. There are signs of the outbreak plateauing in Europe, but I think a very precautionary approach, given these genetic changes, is warranted.”

Epidemiology and transmission

Prof Grulich, head of the Kirby Institute’s HIV Epidemiology and Prevention Program, delved into the epidemiology and current data of the monkeypox outbreak. Looking at studies that have taken place in the UK and USA, cases of monkeypox are almost all attributed to sexual contact, and are overwhelmingly concentrated (over 95 per cent) among gay, bisexual and other men who have sex with men. About 1-2 per cent of cases are among women, and in UK statistics, around 40 per cent of those are transgender women. 

“Household transmission has been very uncommon thus far; it is sexually transmitted in 98 per cent of cases,” said Prof. Grulich. Nevertheless, he said the virus is theoretically transmissible through contact with an infectious animal, human, or fomites (eg bedding or towels) and through broken skin, and that the infectious period is from the onset of symptoms until the rash has resolved. Thus far, there is no evidence of aerosol or airborne transmission. 

Prof Grulich noted that the absence of confirmed aerosol transmission was “quite remarkable when we consider that this disease emerged after massive Pride celebrations in Europe, when there was very limited transmission except between gay men, even in the context of shared dance floors between thousands, sometimes tens of thousands of people.”

The current isolation period for people with monkeypox is 21 days, but given the growing evidence that the virus is predominantly sexually transmitted, and not airborne, Prof Grulich suggested that the long insolation period could be reduced. “21-day isolation was appropriate at the start, as we were concerned about casual transmission. But it has evolved into an almost entirely sexually transmitted condition. While it is still early days and we need more data, we should be thinking about reducing isolation requirements so people don’t have to isolate for 3 weeks unless they have ongoing lesions in exposed skin areas.”

Considering the public health response

Mr Paynter highlighted the role of community organisations and advocates in ensuring a community-centred response through informed health promotion and education. He highlighted the need for public health messaging around monkeypox to balance messaging that is targeted to the affected population - gay and bisexual men - while ensuring messaging is not stigmatising.

He said, “The legacy of the last forty years of HIV health promotion means that gay and bisexual men are engaged in positive health-seeking behaviours, and will want to do the right thing for their own health and the health of their communities.” 

Mr Paynter said the key messages were to monitor for symptoms and test, that vaccines are recommended for all sexually active gay and bisexual men, and that short-term condom use could offer protection against onward monkeypox transmission from people recovering from infection. He also said that vaccine distribution should prioritise people who are immune-compromised, travelling to settings where there are cases of community transmission, or those who have regular sexual partners or have had a recent STI. 

In considering a policy on isolation, Mr Paynter said there should be adequate paid sick leave, employer support for people who need multiple weeks away from work to recover from monkeypox infection, and that isolation needs to be sensitively implemented to ensure it does not jeopardise community confidence in engaging healthcare. The risk of not doing so, he said, could lead to people avoiding health services for fear of being exposed to isolation and self-diagnosing themselves with monkeypox. The outcome of this situation could also lead to people “misdiagnosing themselves with another condition such as syphilis or HIV, which would be very challenging for their health.”

He also posed a number of questions for consideration when developing the public health response. These included how to distinguish the types of skin-to-skin contact to delineate high versus low risk of transmission, what is the role of telehealth, what does a sensible monkeypox isolation policy look like, and how to ensure vaccine rollout reaches those most at risk. 

Mr Paynter concluded his presentation by highlighting that “everyone has a role to play in reducing the risk of stigma. It is my concern with monkeypox that when we start seeing images of sick people in Australia, we may experience a situation where demeaning language is used towards our communities, and that it will be weaponised in ways that are very harmful. So I want to ask everyone to think about how we can call out disparaging and derogatory behaviour if and when it happens.”

As monkeypox evolves, what’s next?

In a panel discussion facilitated by the Kirby Institute’s Professor Miles Davenport, the speakers delved further into questions around the virus and its management. Prof Grulich explained that despite being predominantly sexually transmitted, monkeypox is not defined as an STI, partly due to its transmission via non-intact skin-to-skin contact in other, non-sexual contact settings. But how the outbreak evolves will come down to how we manage it now, and our preparedness coming into Australian summer. 

“I think part of the reason why monkeypox has been relatively slow to take off in Australia has been to do with the fact that it’s winter, and there are limited opportunities for skin-to-skin contact compared to summer with mass gatherings," he said. “So, it may be that come summer, there will be more exposure, and it certainly points to the need to try to get that vaccine coverage as high as we can before then”. 

Mr Paynter agreed. “I think that we should expect that there will be more locally acquired cases in Australia. We also had our borders closed for a long time with COVID and they reopened during the onset of the colder part of the year. I think we’ll see a lot of overseas travellers who may bring this to Australia as we head into summer, so I think Australia should be prepared for an increase in locally acquired transmission.”

Prof MacIntyre also raised the evidence around viral mutation, saying that she is “still concerned about the mutations and the evidence that it’s continuing to mutate and adapt to humans and what that means. I think we shouldn’t be complacent and we need to be quite aggressive in trying to control this outbreak.” In considering how best to distribute a limited vaccine supply, she said “You don’t want to miss the boat; you have to think about when the big exposures are going to be and utilise your vaccines in a smart way. We need to think about exposure risks and epidemiology when there is a limited supply to try and really optimise the protection.”

The researchers said that as more information comes to light, the approach to controlling monkeypox should evolve. Lower vaccine dose could be considered to ensure a larger number of people are afforded protection. Prof Grulich said that while the 21-day isolation period was appropriate in the early days of the outbreak, now that the evidence is indicating sexual contact as the main mode of transmission in Australia, this could be reconsidered. “It is still early days and we need more data, but if it continues to be predominantly sexually transmitted, then it doesn’t seem logical to keep people at home for 3 weeks,” he said.

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Header image: Samuel F. Johanns from Pixabay