Public Health Agency of Canada Expert Panel on Mpox in Canada: Meetings

Opening remarks

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The Chief Science Officer, Dr. Sarah Viehbeck, and the Chief Public Health Officer of Canada, Dr. Theresa Tam, provided opening remarks for the meeting. 

The objectives of the meeting were to:

1. facilitate understanding of the current mpox transmission internationally, with a focus on the emergence and spread of clade Ib in the Democratic Republic of Congo (DRC) and region
2. share information on the current landscape of clade IIb mpox transmission in Canada
3. discuss preparedness and response for potential Clade Ia/Ib transmission in Canada

Agenda overview and administrative updates

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Participants were invited to raise declarations of affiliations and interest with respect to the meeting's agenda items. Additional declarations were noted.

Situational update on mpox

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Dr. Jill Norman, Executive Director in the Centre for Communicable Diseases and Infection Control, provided a situational update on mpox from the Public Health Agency of Canada.

New temporary recommendations, which apply to countries that are currently experiencing an upsurge in cases, were issued by the WHO following declaration of a mpox Public Health Emergency of International Concern on August 14, 2024.  

At the time of this meeting, the clade Ib outbreak continues to be largest in the Democratic Republic of the Congo (DRC) and clade Ib has emerged in multiple countries neighbouring eastern DRC, as well as travel-related cases in Thailand and Sweden. A total of 180 mpox clade IIb cases have been reported in Canada between January 1 and August 20, 2024.

Mpox has been added to Canada's list of Notifiable Diseases Online and reporting processes, wastewater monitoring has expanded to detect clade I, an updated rapid risk assessment including clade Ia and Ib has been posted and sequence confirmation of all clade I samples is occurring at the National Microbiology Laboratory.

Key issue: Update on mpox in Ontario

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Dr. Jessica Hopkins, Chief Health Protection and Emergency Preparedness Officer at Public Health Ontario (PHO) and Dr. Rita Shahin, Associate Medical Officer of Health for Toronto Public Health, presented on the current mpox situation in Toronto and more broadly in Ontario. The purpose of the presentation was to provide an understanding of the Ontario context for mpox incidence, diagnostics and testing, immunisation eligibility and uptake as well as on the actions of PHO to date.

Dr. Hopkins highlighted that PHO utilizes a multiplex assay that detects two targets: one generic that detects clades I and II and one specific which only detects clade II. A specific PCR target to detect clade I is under development by PHO. Positivity of tested samples is greater than 25% since the end of June 2024. Percent positivity of under 5% indicates low mpox activity. In Ontario, all cases have been clade IIb, of which 95% are male with 85% of cases reporting no travel during their incubation period, which suggests infection acquired in Ontario. Dr. Shahin explained that the majority of the cases are in Toronto (84%) with most cases clustered in the city's downtown core.

In relation to immunisation, Dr. Hopkins shared that most cases have not completed 2 doses of Imvamune (85%) and further investigation regarding timing of doses is occurring for those cases that are fully immunised (15%). In Toronto specifically, Dr. Shahin shared that 72% of the cases report not having received either dose of vaccine.

Key issue: Mpox Central Africa situation update and ongoing IMReC initiatives in the region

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Dr. Jason Kindrachuk, Associate Professor and Canada Research Chair, Manitoba Centre for Proteomics and Infectious diseases, provided a situational update on the mpox outbreak in central Africa and the ongoing International Mpox Response Consortium (IMReC) activities. Dr. Kindrachuk highlighted the epidemiologic evolution of mpox in the Democratic Republic of the Congo cautioning against the comparison between clades regarding clinical severity and case fatality rates while evidence continues to evolve. Epidemiologic data was presented to highlight the overrepresentation of infections and severe and fatal disease amongst those under 15 years of age, the appearance in 2023 of cases which clustered independently of clade Ia (zoonotic) cases, the following expansion of clade Ib to other areas of the DRC and the continued transboundary movement of clade Ia cases. The presentation included mpox vaccine deployment modelling results.

Discussion was centred on treatment availability and clinical trial studies, the need for alternative therapeutics, gaps in understanding of current animal reservoir host populations and the need for serosurveillance in Africa, and in Canada.

Roundtable

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Panel members and participants engaged in discussions on preparedness planning for clade Ia and Ib importation into Canada, with consideration of knowledge gaps and research needs identified in 2022 that continue to be relevant to the current context.

Conclusions and next steps

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Discussions during the meeting supported an interest and need for a follow up expert panel meeting. Details on date and topics of discussion will be communicated to panelists in the near future.