Canada’s progress in implementing poliovirus containment

Abstract

Background: The goal of the Global Polio Eradication Campaign is to eliminate the remaining poliovirus circulating in human populations. Once eradicated, polio immunization rates are expected to decline and the only source of poliovirus will be in laboratory facilities, which poses a risk for re-introducing poliovirus into susceptible human populations.

Objective: To develop and implement a robust poliovirus containment and monitoring program in Canada to support global polio eradication efforts.

Methods: The Public Health Agency of Canada's Centre for Biosecurity (PHAC-CB) established the National Authority for Containment (NAC Canada) to oversee World Health Organization (WHO)'s Global Action Plan (GAP) for Poliovirus Containment. Facilities that entered into the GAP Containment Certification Scheme were designated as Poliovirus Essential Facilities. With the goal of reducing poliovirus material storage in Canada, and for containing the existing poliovirus stocks, the NAC Canada established inventories, audited and certified Poliovirus Essential Facilities, completed GAP training and qualified auditors and performed stakeholder outreach.

Results: Canada was among the first countries to qualify GAP auditors under the Containment Certification Scheme and was the first country in the world to move onto the second stage of poliovirus containment, when a Canadian Poliovirus Essential Facility was awarded the first Interim Certificate of Containment (ICC). The Canadian national poliovirus inventory, maintained by NAC Canada, leveraged the PHAC-CB Biosecurity Portal and stakeholder outreach (including surveys, website, newsletters, webinars) to identify sources of poliovirus and potentially infectious materials. From 2018–2024, the number of facilities in Canada storing wild type and Sabin poliovirus were reduced by 82% and 89%, respectively. In 2022, a multi-jurisdictional emergency exercise was conducted to evaluate coordinated response mechanisms for a simulated laboratory release of poliovirus. The Risk Group classification of human polioviruses in Canada was increased to Risk Group 3 (RG3) in 2023, to better align with the WHO GAP containment requirements.

Conclusion: Canada's NAC is collaborating with national stakeholders and international partners towards the goal of poliovirus eradication. Containment and monitoring efforts to reduce poliovirus in storage and to verify that Canadian Poliovirus Essential Facilities meet both federal legislative requirements and GAP biorisk management elements are key to health security in the current and post-polio eradication worlds. Canada's NAC activities will continue working towards decreasing the risk associated with poliovirus to safeguard the health and safety of Canadians.

Introduction

The international campaign to eradicate polio has achieved significant progress since the Global Polio Eradication Initiative (GPEI) was initiated in 1988 ^{Footnote 1}. Since then, the number of polio cases has been reduced by 99.9% and two of the three wild poliovirus types (wildtype poliovirus types 2 and 3; WPV2 and WPV3) have been eradicated from circulation in human populations ^{Footnote 2Footnote 3}. Among these successes come new challenges, as wild poliovirus type 1 (WPV1) persists in two endemic countries (Afghanistan and Pakistan) and circulating vaccine-derived polioviruses (cVDPV) can emerge from oral poliovirus vaccine (OPV) use in under-vaccinated populations ^{Footnote 2}. Once WPV1 circulation has been stopped and OPV use has been discontinued, polio immunization rates are expected to decline and the only source of human polioviruses will be in laboratory facilities in the form of samples and culture collections ^{Footnote 4}. Canada, along with World Health Organization (WHO) member states, has recognized the importance of minimizing the risk of facility-associated release of polioviruses into susceptible human populations in a post-eradication world.

Under World Health Assembly resolution 71.16, Canada has committed to the containment of polioviruses ^{Footnote 5}. The WHO set a target date of 2026 for all poliovirus and poliovirus materials to be under the full containment requirements set out in the Global Action Plan (GAP) for Poliovirus Containment IV (GAPIV) ^{Footnote 4}. The GAPIV sets out strict biorisk management elements to contain polioviruses in Poliovirus Essential Facilities (PEFs), which are designated by the National Authority for Containment (NAC) on the basis that the facility serves a critical national or international function in vaccine production, research or public health diagnostics. The GAPIV considers containment for all poliovirus materials under a common biorisk standard, replacing the former Global Action Plan III (GAPIII), which focused on immediate containment of WPV2 materials ^{Footnote 6}. Poliovirus Essential Facilities acquire certification through the rigorous Containment Certification Scheme (CCS) process, which defines the roles and responsibilities, oversight and audit requirements for storing and working with polioviruses ^{Footnote 7}. Ongoing monitoring of Canadian facilities for compliance against the GAP is critical, as accidental poliovirus containment breaches have occurred at vaccine manufacturers, such as in the Netherlands (2017 and 2022), Belgium (2014) and France (2018 and 2024) ^{Footnote 8Footnote 9Footnote 10Footnote 11Footnote 12}. Importation of poliovirus from endemic countries has led to outbreaks in other global health regions, such as in WHO African Region (Malawi and Mozambique) ^{Footnote 13}, and Canada remains at risk for travel-associated importation of poliovirus ^{Footnote 14}. In 2022, poliovirus shedding linked to international travel was detected through genomic wastewater surveillance; however, no cases of poliomyelitis were identified in Canada ^{Footnote 15Footnote 16}. In parallel, the ongoing development of engineered attenuated poliovirus strains (e.g., OPV and S19) ^{Footnote 17Footnote 18} reinforces the need for sustained public health surveillance and stringent containment of poliovirus materials in Canada.

The Public Health Agency of Canada's Centre for Biosecurity (PHAC-CB), serving as Canada's NAC, is working to reduce the number of facilities storing polioviruses in Canada and to ensure only certified facilities hold poliovirus materials under GAP containment requirements ^{Footnote 4Footnote 6}. This article presents Canada's progress in implementing poliovirus containment, working towards the goal of a polio-free world and keeping Canadians healthy, safe and secure.

Intervention

Establishment of the National Authority for Containment of Poliovirus (Public Heath Agency of Canada's Centre for Biosecurity)

In 2015, NAC Canada was established within PHAC-CB to provide oversight on poliovirus containment in Canada and coordinate GAP certification with WHO's Global Certification Commission-Containment Working Group (WG). The PHAC-CB is mandated to protect the health and safety of Canadians against the risks posed by human pathogens and toxins by administering Human Pathogens and Toxins Act (HPTA) ^{Footnote 19} and Human Pathogens and Toxins Regulations (HPTR) ^{Footnote 20}. The PHAC-CB Office of Biosafety and Biocontainment Operations Director serves as the National Poliovirus Containment Coordinator to coordinate with WHO and international NACs on containment issues. There are six members of NAC Canada who are employees of PHAC-CB, whose primary roles are in administering the HPTA by working in Canada's national biosafety and biocontainment inspection program.

Containment certification scheme process: National poliovirus inventory, Global Action Plan audits and certification plan

As the national regulator, PHAC-CB inspectors verify compliance with the HPTA, HPTR and the Canadian Biosafety Standard, 3^rd edition ^{Footnote 21} in Canadian facilities performing controlled activities with human pathogens and toxins. Through the inspection and licensing process, PHAC-CB maintains records on known poliovirus storage in Canada. An initial survey captured information on polioviruses as part of the HPTA registration process and outreach for import permits (2009–2015), followed by further surveys during the HPTA application process (2016). Additional outreach to non-HPTA regulated facilities was conducted (2016–2022) to identify other possible locations for poliovirus and potentially infectious material (PIM) storage, such as anthropology departments, water treatment facilities and pharmaceutical companies.

Facilities were encouraged to destroy existing poliovirus materials, transfer materials to approved facilities or begin the process to become a certified PEF (Figure 1). Facilities that chose to retain materials, and that were deemed by NAC Canada to serve an essential function (e.g., public health or research laboratories, vaccine manufacturers), were endorsed by the NAC and designated as PEFs to enter into the CCS process. Canada's NAC conducted an initial gap assessment (2018–2019) of these designated PEFs, including extensive site interviews, document reviews and physical verifications of the facilities. Applications were submitted for a Certificate of Participation to WHO-Global Certification Commission-Containment WG in 2019 and were approved in 2020. Canadian PEFs underwent full audits against the third edition of the GAP (GAPIII) in 2021, as NAC auditors focused on elements including safety management systems, biorisk management, research, diagnostics, production environments, engineering principles and concepts, emergency preparedness and security. Canadian NAC auditors identified corrective actions for designated PEFs to complete before they could be fully compliant with GAPIII. Upon confirmation that identified deficiencies were corrected, NAC Canada and PEFs prepared the Interim Certificate of Containment application packages and submitted to WHO-Global Certification Commission-Containment WG in 2022–2023.

Figure 1 - Text description

This figure outlines the formal process a Canadian facility must follow to achieve full poliovirus containment certification, or to dispose of poliovirus materials (WPV, OPV and cVDPV). Canadian facilities seeking to enter into the poliovirus Containment Certification Scheme process would require a Risk Group 3 Pathogen and Toxin Licence under the Human Pathogens and Toxins Act. As part of the formal certification process to retain or acquire poliovirus materials, NAC Canada performs an initial gap assessment against World Health Organization (WHO) Global Action Plan (GAP) requirements, such as inventory and staff training elements. Once NAC Canada has designated the facility as a PEF, formal GAP audits are performed and an application for a Certificate of Containment is submitted to the WHO.

If a facility no longer wishes to retain poliovirus materials, they must proceed with the disposition process. This process involves either transferring materials to a PEF certified facility or destroying and/or inactivating the materials by approved disposal methods. A disposition form is submitted to NAC Canada (PHAC-CB) to document this process, and to confirm the facility no longer handles or stores polioviruses.

Outcomes

National Authority for Containment Canada and the national poliovirus inventory

Establishing NAC Canada under the PHAC-CB was a key step in rapidly advancing poliovirus containment in Canada, as the existing regulatory structure for laboratory facilities was already in-place. Under the HPTA, Canada has the legal framework to require the containment of polioviruses which have been classified as Risk Group 3 (RG3) pathogens since November 2023 (see below in Outreach and communications). Canada's poliovirus activities (Table 1) include PHAC-led initiatives to accelerate the full implementation of the GAP containment requirements, complete polio inventories and destroy unnecessary materials and continue to reduce the number of facilities storing polioviruses. Canada's RG3 classification and Canadian Biosafety Standard, 3^rd edition requirements align with WHO's GAPIV biorisk management elements for poliovirus containment ^{Footnote 4}. The national poliovirus inventory is updated using information entered by regulated parties into the secure PHAC-CB Biosecurity Portal when licence applications under the HPTA are submitted. Between 2015–2023, there was an 82% decrease in the number of Canadian facilities with wild type poliovirus materials and an 89% decrease in facilities with OPV Sabin materials. Initially from 2015, GAPIII containment requirements were focused on poliovirus type 2 infectious materials (WPV2, cVDPV2, oral polio vaccine type 2 [OPV2]) and type 3 materials were under containment requirements since 2019. Canada was proactive in developing the inventory, capturing all poliovirus materials through surveys and outreach in-advance of WHO's type-specific requirements. Approximately 350 applications are received annually in Canada for new licences, renewals and amendments. No new facilities have planned to enter the poliovirus CCS process since HPTA licensing was implemented in 2016.

Attenuated poliovirus strains which are not included by WHO under GAP containment requirements (novel oral poliovirus [nOPV], S19 strains, polio-rhinovirus chimera [PVSRIPO]) are still regulated by PHAC-CB under the HPTA and Canadian Biosafety Standard, 3^rd edition and are tracked as part of Canada's national poliovirus inventory. In particular, nOPV vaccine strains, which were engineered to be more genetically stable and less likely to revert to WPV-like cVDPV polioviruses, have continued to cause polio outbreaks ^{Footnote 22} and require ongoing compliance monitoring and verification in laboratory facilities by PHAC-CB. Furthermore, PIM may be a source of polioviruses and WHO has published a guidance document to mitigate the risk of these materials ^{Footnote 23}. Potentially infectious material includes human fecal or respiratory samples, sewage samples, or their derivatives, that were collected at a time and place where poliovirus was in circulation (including use of OPV Sabin vaccines). Polioviruses in clinical or environmental samples can survive indefinitely in laboratory freezers, or months stored in the refrigerator ^{Footnote 24}. The PHAC-CB/NAC Canada's survey for PIM contacted 1060 organizations over a period of five years. This outreach identified no additional facilities possessing poliovirus PIM, or facilities had destroyed any potential materials.

Poliovirus Essential Facility audits and containment certification scheme results

Canada was among the first countries in the world to qualify auditors and perform audits under the 2015 published edition of the GAPIII in 2021 ^{Footnote 6}. All Canadian GAP auditors are members of NAC Canada, are experts in microbiology, biosafety and engineering, and were qualified based on their extensive education, training, experience and security clearance. As of 2024, the four qualified NAC Canada GAP auditors have over 278 estimated days of collective laboratory auditing experience, plus specific training in biorisk management and GAP auditing of PEFs. For facilities indicating they planned to continue activities with polioviruses post-eradication, gap assessments were conducted and identified areas for improvement before full GAPIII certification audits were planned. Two facilities went through to the Certificate of Participation application stage of the CCS, while other facilities communicated the intention to dispose of poliovirus materials. At the time (2021), facilities were audited under GAPIII elements ^{Footnote 6}, but NAC Canada plans to conduct new audits to verify compliance to the revised GAPIV international standard ^{Footnote 4} in advance of the final Containment Certification stage of the CCS. In general, audits discovered only minor nonconformities in training, documentation and general processes, which were remedied by corrective actions.

Following this GAPIII audit and application process, Canada was the first country to advance to the second stage of poliovirus containment, when a designated PEF was awarded an Interim Certificate of Containment in October 2022 ^{Footnote 25Footnote 26}. This key milestone exemplified Canada's substantial progress in poliovirus containment, while WHO has noted delays in other countries establishing NACs and creating poliovirus inventories ^{Footnote 27Footnote 28}. At the time of the preparation of this manuscript, PHAC-CB/NAC Canada was initiating the GAPIV audit process in Canada.

Outreach and communications

Canada's increase to Risk Group 3 and Containment Level 3 for human polioviruses

After a review and updating the pathogen risk assessment on human polioviruses, PHAC-CB recommended increasing the RG classification to RG3 and Containment Level (CL) classification to CL3. This recommendation was considered by the HPTA Advisory Committee ^{Footnote 29} and approved in 2023. The HPTA-regulated parties were informed of the change in October 2023 and provided with three options if they performed controlled activities with polioviruses: 1) transfer materials to a certified PEF; 2) destroy materials through approved methods; and 3) apply for a RG3 licence under the HPTA and begin the CCS process to become a PEF. Outreach surrounding the increase in classification to RG3/CL3 resulted in a reduction of facilities retaining polioviruses, as well as identifying additional materials which were destroyed by approved protocols.

Additional outreach and reporting

In addition to survey activities, PHAC-CB communicates with HPTA-regulated parties in Canada regarding poliovirus containment activities through a website ^{Footnote 30}, a quarterly newsletter ^{Footnote 24}, webinars and by offering training. Canada's NAC engages international partners in discussing best practices on facility audits, including serving as the Chair of the International NAC group in 2023–2024. Annually, WHO member states report on their progress towards polio eradication goals through their respective WHO regional arm. Canada's report is prepared through a collective effort of multiple Health Portfolio areas and submitted to the Pan American Health Organization. The PHAC-CB is responsible for the poliovirus containment section and reports on overall inventories. In addition, NAC Canada provides input into international documents and initiatives, including the World Health Assembly, reviewing resolutions and poliovirus containment-related processes (such as the revision of the GAP). Nationally, PHAC-CB also coordinated with Health Canada to remove polioviruses from the list of surrogate organisms prescribed for testing the efficacy of chemical disinfectants ^{Footnote 31}.

Polio outbreak simulation exercise

Although Canada is rated as a low-risk country for polio according to the Pan American Health Organization ^{Footnote 32}, planning and vigilance are important in preparing for potential poliovirus events. In 2022, PHAC held a Polio Outbreak Simulation Exercise (POSE) table-top exercise based on a simulated, unintentional laboratory containment breach involving poliovirus. Over 40 exercise participants from multiple Canadian jurisdictions discussed the coordination, response roles, governance and operational structures that would be involved in an accidental poliovirus event. As part of the table-top exercise, participants reviewed Canada's national polio response protocol, Guidance for the response and management of a poliovirus event or outbreak in Canada ^{Footnote 33}, the Federal/Provincial/Territorial Public Health Response Plan for Biological Events ^{Footnote 34} and WHO's Public health management of facility related exposure to live polioviruses ^{Footnote 35}. Emphasis was placed on rapid detection, notification and investigation made to support timely implementation of public health controls, limiting potential spread and promoting knowledge-sharing among Canadian partners.

Conclusion

Canada is a world leader in biosafety and biosecurity, as recognized in the 2018 International Health Regulations—Joint External Evaluation Report ^{Footnote 36Footnote 37} and has reached important milestones in poliovirus containment as part of the global campaign to eradicate polio. Between 2017–2024, through engagement (outreach, training, education and regulatory oversight), Canada reduced the number of facilities with poliovirus materials by approximately 80%–90%, depending on the type. Despite the challenges, work continues to identify potential sources of poliovirus, promote containment and biorisk management, audit facilities for compliance with the GAP and national legislation and collaborate with our international partners. The ongoing circulation of WPV1 and cVDPVs in human populations threatens re-emergence of polio unless complete eradication is achieved. The use of polioviruses in vaccine production, as well as the development of new strains of poliovirus (novel OPV, S19 strains, PVSRIPO), requires ongoing vigilance by PHAC-CB inspections to verify all Canadian facilities remain HPTA compliant. In both the current and post-eradication world, containment is critical to mitigate the risk of polioviruses accidentally being re-introduced into the human population. Canadian organizations are encouraged to contact PHAC-CB regarding questions on poliovirus PIM, or any biosafety or biosecurity issue. This paper has detailed Canada's substantial progress and successes in poliovirus containment. The PHAC-CB/NAC Canada looks forward to continuing working with national and international partners in biosafety and biosecurity to keep Canadians healthy and safe.

Authors' statement

DT — Conceptualization, formal analysis, visualization, writing–original draft, writing−review & editing
LM — Writing−review & editing, investigation, formal analysis, supervision
DL — Writing−review & editing, investigation, formal analysis
DB — Writing−review & editing, investigation, formal analysis
CR — Writing−review & editing, investigation
AB — Writing−review & editing, investigation, project administration

Competing interests

None.

ORCID numbers

None.

Acknowledgements

The authors thank all the staff of the Public Health Agency of Canada, including the Centre for Biosecurity, and our colleagues in the Regulatory Operations and Emergency Management Branch, the Infectious Diseases and Vaccination Programs Branch, and the National Microbiology Laboratory Branch. The authors thank Canadian regulated parties and all facilities that have worked collaboratively towards implementing poliovirus containment in Canada.

Funding

This work was supported by the Public Health Agency of Canada.

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