GPEI-What’s next for the novel oral polio vaccine type 2 (nOPV2) now that it’s been WHO-prequalified?

19 February 2024

In December 2023, novel oral polio vaccine type 2 (nOPV2) made history by becoming the first vaccine to move from use under a WHO Emergency Use Listing (EUL) recommendation to full licensure and WHO prequalification. We catch up with Chair of the GPEI’s nOPV Working Group Dr. Ananda S. Bandyopadhyay, from the Bill & Melinda Gates Foundation, the Chair of GPEI’s Vaccine Supply Group Ann Ottosen, from UNICEF’s Supply Division, and WHO African Region’s Polio Eradication Coordinator Jamal Ahmad to discuss how things have changed in terms of nOPV2’s use, and next steps for this innovative tool.

Welcome Ann and Jamal, and welcome back, Ananda. A lot has happened in the past three years since nOPV2 was first used in the field under EUL. Prequalification is a big milestone. Tell us about this achievement.

Ananda

Hello – good to be speaking with you again. Yes, the WHO Prequalification (PQ) of nOPV2 is a major milestone for global public health, as this is the first example of a vaccine making the transition from EUL use to PQ. In fact, nOPV2 was the first vaccine to achieve an EUL authorization – the same process that has since been used to accelerate access to thirteen COVID-19 vaccines – so another ‘first’ for public health there.

When I look back at this journey, I feel immensely thankful to so many partners and collaborators across the world who joined this effort since it began back in 2011. Since then, we’ve gone from idea generation to pre-clinical and clinical development, to manufacturing at-scale, and then to EUL authorization for field use in November 2020. Over the past three years, there’s been rollout at a massive scale, with nearly 1 billion doses administered across 35 countries by the time full licensure from Indonesian regulatory authority (BPOM) and PQ was issued in December 2023. This truly is an example of scientific innovation being translated into global health action through a worldwide collaborative effort.

What does nOPV2’s prequalification mean for countries? What are some of the benefits of the vaccine being PQ’d?

Jamal

The prequalification of nOPV2 represents a big advancement in the global fight against polio, particularly in managing and mitigating outbreaks of type 2 variant poliovirus (cVDPV2), the most prevalent form of the variant virus. Almost 95% of the vaccine used to date has been in African countries where there is the biggest burden of cVDPV2 outbreaks.

Throughout its use under EUL, GPEI and countries have rigorously collected and analysed data on the vaccine’s performance and PQ signals the final, formal endorsement of nOPV2’s safety and efficacy. This has several key benefits, including a streamlined process for countries that wish to use it. Ultimately, PQ facilitates a quicker response to cVDPV2 outbreaks with a vaccine that has a much lower likelihood of seeding new outbreaks.

Ann

Preparation for use of the vaccine under EUL was a time- and resource-intensive process for both the GPEI and countries. Countries needed to meet several requirements across numerous functional areas to access and use the vaccine, including local approvals, cold chain and vaccine management, surveillance, safety and advocacy, and communications and social mobilization. A readiness verification team of the GPEI would review country performance on these criteria before UNICEF would be authorized to deliver doses from the global stockpile to the country. Now that the vaccine is prequalified, these requirements have been lifted.

Would you say demand for nOPV2 has changed since prequalification?

Ann

nOPV2 is now the preferred tool to stop type 2 variant polio and, because of ongoing outbreaks, demand for the vaccine has unfortunately increased. In addition, since countries no longer must meet the rigorous readiness requirements to use the vaccine that I described above, it is easier and quicker for them to request it.

nOPV2 is accessible through the Global OPV Stockpile – a unique mechanism for the type 2 polio vaccines used in outbreak response, and only following release by the WHO Director-General upon technical review and endorsement of a country application. The number of doses in this stockpile is planned far in advance with the manufacturer based on forecasted demand from the GPEI, and the vaccine in the stockpile is only produced to order as there are no commercial markets for nOPV2 and production lead times are up to a year. Therefore, it is critical to secure enough supplies that the forecasting is correct and production runs smoothly.

Jamal

The demand for nOPV2, particularly in African countries, continues to be high with it being the vaccine of choice when it comes to responding to type 2 variant polio outbreaks. As the program aims to get ahead of the virus with large scale outbreak responses, we hope to see a significant decline in demand for the vaccine in the coming years as outbreaks are closed.

Given the current demand, how are we tracking in terms of supply? From our last conversation, it seemed sufficient at the time but has the situation changed?

Ann

So far, we have been dependent on a sole supplier, which has produced 1.4 billion doses of the vaccine since nOPV2’s field use began in March 2021. This is truly a massive scale up over a short period of time. However, vaccines are biological products, and the manufacturing processes are very sensitive. Since November 2023, due to unexpected delays in maintenance and testing procedures, we are experiencing a disruption in supply with filling of new vaccine temporarily paused. This problem has yet to be resolved and the GPEI is working closely with the manufacturer to identify the root cause, remediate the issue, and restart production as soon as possible.

Since the program had planned an aggressive schedule for large-scale outbreak response activities in Q1 2024, there was an initial need for 330 million doses of the vaccine. However, because of the current supply disruption, the program is prioritizing available nOPV2 to respond to outbreaks in the highest risk areas. With this prioritization, more than 200 million doses have been or will be delivered to countries in Q1 of this year. We are hopeful that more supply will become available in May 2024 to address any postponed activities.

Jamal

The current supply challenges will be a speed bump on the road to ending type 2 variant poliovirus in Africa, however, measures are being taken to address these challenges in the region and reduce their impact on the overall goal of eradication. As Ann touched on, we are adapting our outbreak responses accordingly, with an immediate focus on areas of highest need that pose a risk of international spread and we believe we will remain on track.

Ananda

I would also like to note that when you look across the different vaccines available in global supplies, issues like what we are seeing now with nOPV2 are common. In fact, this is expected given the massive demand for the vaccine and the rapidity with which the scale up and supply readiness steps had to be implemented due to the serious emergency that cVDPV2 outbreaks constitute.

As such, the GPEI has been working to engage an additional manufacturer. While the program remains confident in the current manufacturer’s continued capacity as a supplier of nOPV2, as with any vaccine, having a diversity of suppliers is important to help ensure supply meets demand. This second supplier is expected to begin filling vials with nOPV2 and finalizing the product for shipment by mid-2024, with full production capacity expected by the end of the year. This will help address the current shortage of the vaccine and reduce the risk of supply disruptions in the future.

Some countries, for example Nigeria, are using a lot of nOPV2 but are still battling transmission. What kind of tactics will be taken in these places?

Jamal

Nigeria is a good example of the last mile challenges in the eradication effort. It is a large country with a very large population, which means huge cohorts of vulnerable children. In addition, ongoing challenges like inaccessibility, insecurity and vaccine hesitancy in the country have led to pockets of communities where the traditional methods of reaching children are not as effective.

A multifaceted, tailored approach in these places is therefore essential to get to zero. The program continues to work with local authorities to implement new geospatial technologies to inform outbreak response microplanning, enabling teams to more consistently find and reach missed populations. This, combined with efforts to engage local leaders in the most insecure areas, are helping ensure no child is left unprotected from this devastating, preventable disease. In addition, enhanced surveillance systems and improved cold chain infrastructure will continue to be critical to facilitate rapid alert and responses to potential polio cases.

It is possible for confined transmission of the virus in a small part of the country to find its way to large population centres and lead to massive outbreaks. Therefore, periodic intensified large-scale vaccination and public awareness campaigns, coupled with targeted vaccination drives in high-risk areas with persistent transmission, are also necessary to keep the virus cornered.

Lastly, on nOPV2’s genetic stability. How’s that going? Is it still performing at the same level?

Ananda

After almost three years of large-scale nOPV2 use, all data demonstrates that nOPV2 has about 80% lower risk of seeding new type 2 variant poliovirus outbreaks compared to its predecessor, mOPV2. nOPV2 has proven to be an important tool that will help the program more sustainably stop the virus.

However, the bottom-line remains that the success of nOPV2, like any polio vaccine, depends on the ability to rapidly implement vaccination campaigns in response to outbreaks that reach every child. We are confident that with the help of global, regional and country partners, and most importantly the frontline health workers visiting communities, we will interrupt variant poliovirus transmission once and for all.

In late December 2023, the World Health Organization issued its first-ever prequalification approval for a vaccine being used under its Emergency Use Listing (EUL) regulatory pathway – novel oral polio vaccine type 2 (nOPV2). Since rollout of this next-generation vaccine began in March 2021, the Global Polio Eradication Initiative (GPEI) has administered nearly 1 billion doses of nOPV2 across 35 countries, protecting millions of children against illness and paralysis. Prequalification will enable additional countries to access the vaccine more easily for more sustainable response to outbreaks of type 2 variant poliovirus (cVDPV2).

“This is a historic milestone for polio eradication and for public health,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus. “Novel oral polio vaccine type 2 has blazed a trail for other new vaccines that address critical health emergencies, and its use demonstrates the utility of the EUL mechanism in helping to rapidly get new products to where they’re needed most.”

The EUL to PQ pathway

WHO EUL is reserved for the use of yet-to-be-licensed vaccines, medicines and diagnostic tools during public health emergencies like polio outbreaks. Following rigorous assessments of existing quality, safety and efficacy data from completed clinical trials, the pathway enables expedited availability of products to the places impacted by these emergencies. The vaccine’s manufacturer, Bio Farma Indonesia, has been instrumental in ensuring supply and enabling nOPV2 to earn full licensure from the Indonesian regulatory authority, Badan POM. WHO Prequalification (PQ) is the final step of the process, allowing for streamlined regulatory approval for nOPV2 use in countries that need it.

“This key step illustrates how innovation can help protect children against the variant poliovirus type 2, with thanks to the support of donors and partners, and the commitment of governments and community health workers,” said UNICEF Executive Director Catherine Russell. “UNICEF is committed to helping ensure the safe and adequate supply of vaccines to countries, while working with communities to build trust in vaccines. We need to keep going till we reach every child, and eradicate polio once and for all.”

nOPV2’s performance and the power of innovation

To date, nOPV2 has been used in 35 countries under EUL, predominantly in the African region which is most affected by cVDPV2 outbreaks. Throughout its clinical development and field use, nOPV2 has proven to be as safe to use and effective at stopping outbreaks as its predecessor, monovalent type 2 oral vaccine (mOPV2), but, importantly, is more genetically stable. After nearly three years of use, estimates show that nOPV2 is 80% less likely to seed new variant polio outbreaks, making it the tool of choice to stop these outbreaks for good.

Nigeria has played an outsized role in nOPV2 rollout in the leadup to WHO Prequalification, administering nearly half a billion doses to children across the country to date. The vaccine has helped bring about an 85% reduction in variant poliovirus cases in Nigeria since 2021, and its impact is visible through this and other data in a new story from the GPEI.

Development of the vaccine began in 2011 through a consortium of experts led by the Bill & Melinda Gates Foundation, including the UK National Institute for Biological Standards and Controls (NIBSC), the U.S. Centers for Disease Control and Prevention (US-CDC), the US Food and Drug Administration, PATH and the University of California at San Francisco.

“Supporting the development of new vaccines is one of the most important investments we can make to protect people against preventable diseases like polio,” said Mark Suzman, CEO of the Bill & Melinda Gates Foundation. “With easier access to nOPV2 for more countries, this vaccine will keep even more children safe in areas still grappling with poliovirus. We look forward to working with partners across sectors to support more groundbreaking innovations.”

Next steps in the fight against type 2 variant poliovirus

As of 3 January 2024, 325 cases of cVDPV2 had been reported in 2023, compared to 689 cases in 2022. While nOPV2 has played a key part in this reduction, its success, like any polio vaccine, depends on the ability to rapidly implement high-quality immunization campaigns that reach every child.

To overcome the final challenges that remain in polio eradication, the GPEI is finding new ways to access children living in hard-to-reach areas, promote community acceptance of vaccines, and improve early detection and response to outbreaks. These efforts are being prioritized in the places where children are at the highest risk of encountering and spreading the virus.

“It is critical to protect all children against polio with timely administration of vaccines. Along with our global partners, CDC is committed to ensuring rapid detection of type 2 polio outbreaks and response with the novel oral vaccine,” said Dr. Mandy Cohen, Director of the US-CDC.

A prequalified nOPV2 will help to make important headway against cVDPV2 outbreaks, and with renewed support from global partners, donors and leaders of polio-affected countries to fully implement the program’s strategy, we can stop all forms of polio for good.

END

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About the GPEI:
The Global Polio Eradication Initiative is a public-private partnership led by national governments with six partners – the World Health Organization (WHO), Rotary International, the US Centers for Disease Control and Prevention (CDC), the United Nations Children’s Fund (UNICEF), Bill & Melinda Gates Foundation and Gavi, the vaccine alliance. Its goal is to eradicate polio worldwide.

For media enquiries:
WHO
For prequalification specific enquiries:
Sarah Sheppard – Communications Officer sheppards@who.int
For polio and nOPV2 enquiries:
Joseph Swan – Communications Officer swanj@who.int

UNICEF
Helen Wylie, Communications Specialist hwylie@unicef.org

Bill & Melinda Gates Foundation
Amber Zeddies, Senior Program Officer amber.zeddies@gatesfoundation.org

US CDC
Chelsea Toledo, Health Communications Specialist rnv8@cdc.gov

In 2011, a major endeavour was launched to develop a more genetically stable version of the monovalent oral polio vaccine type 2 (mOPV2) to more sustainably stop outbreaks of type 2 variant poliovirus. Fast forward to today, and close to 600 million doses of the novel oral polio vaccine type 2 (nOPV2) have been used across 28 countries in outbreak response. We spoke to the co-leads of GPEI’s nOPV Working Group, Simona Zipursky (World Health Organization) and Ananda S. Bandyopadhyay (Bill & Melinda Gates Foundation), to check in on how things are unfolding with deployment and use of this innovative tool.

Simona Zipursky, WHO and Ananda S. Bandyopadhyay, BMGF

Q: Hello Simona and Ananda, and welcome. The vaccine has been used extensively since rollout began in March 2021. How would you say demand for the tool has been over the past two years?

A: Simona – When nOPV2 was first made available in March 2021 following its Emergency Use Listing (EUL) authorization, we weren’t sure what demand would be like to be honest. The EUL was a new pathway for Public Health Emergencies of International Concern at that point—nOPV2 was the first vaccine that received one through WHO—and countries already had access to mOPV2, a proven vaccine that’s effective at stopping outbreaks. On top of that, use of nOPV2 came with an additional set of requirements countries had to meet due to its EUL status—they needed to show they were set up to monitor the vaccine’s performance and safety profile, as well as be ready to address any unexpected findings. But what we saw was high demand right from the outset. I think this was due in large part to our strong collaboration with the WHO and UNICEF regional offices even in advance of the EUL, where we worked together to clearly explain to countries what nOPV2 is, where it had the potential to add value, and what they would need to do in order to use it. By the time the vaccine was available, countries were already aware and able to make informed decisions with their National Immunization Technical Advisory Groups and National Regulatory Authorities on whether it was the right tool for them. Over time, we have seen confidence in the vaccine increase along with demand—last year over 94% of the type 2 vaccine used in outbreak response was nOPV2. I think the strong monitoring of the vaccine’s performance, safety and genetic stability has also really helped build trust in the vaccine. Today, we have used the vaccine in 28 countries, with an additional 13 countries having already met the requirements to use it in case of an outbreak.

Q: 600 million doses administered is a lot of vaccine. Is usage evenly distributed across the 28 countries? And how are we doing in terms of vaccine supply, given the demand?

A: Simona – nOPV2 is not used in routine immunization programs, but only for outbreak response. Like all type 2 polio vaccines it is managed through a global stockpile. For nOPV2 this means that a country can’t just go and ‘order’ the vaccine—the only place it can be sourced from is the global stockpile. To access the vaccine, countries must not just meet the readiness requirements but also submit a risk assessment for the current outbreak, which needs to be approved before the WHO Director-General is asked to release nOPV2 for the response. This means that nOPV2 is distributed based on outbreak needs and risk assessments. While nOPV2 has been used in the European region, Eastern Mediterranean region, as well as the Southeast Asian region, over 95% of the vaccine used to date has been in Africa where there is the biggest burden of type 2 outbreaks. Even within Africa, use of the vaccine varies by country—countries where there is a high burden of type 2 outbreaks have used more vaccine. Nigeria alone accounts for over 60% of global nOPV2 administration.

Supply of nOPV2 continues to be something we monitor closely. We expect to have access to around 600-650 million doses of nOPV2 in 2023—which is more type 2 vaccine than we have ever used for outbreak response in a year. However, while we have a lot of vaccine available this year overall, we don’t have it all available now. So depending on when outbreak response is needed, we may have some months when we are short on supply—that’s something that needs to be consistently monitored and adjusted for.

The other challenging factor for supply is that we are seeing, with the increased confidence in nOPV2 being more genetically stable than Sabin mOPV2 and less likely to seed new outbreaks, that the scope of outbreak responses is increasing, leading to higher demand for the vaccine. We currently only have one global nOPV2 supplier, BioFarma in Indonesia, who are doing an extraordinary job on the manufacturing front. But there is a definite risk to consistent supply and work is underway to have a second manufacturer supplying nOPV2 in 2024.

Q: Let’s talk about effectiveness. Has the vaccine been successful in stopping outbreaks?

A: Ananda – Yes. More than two thirds of all countries that have used nOPV2 for outbreak response did not report continued transmission following two vaccination campaigns. In some areas with persistent transmission, we’ve seen interruption [of transmission] after a third round. There are, however, a few geographic settings where the virus persists despite multiple campaigns, and these are the areas where we need to focus more on reaching missed children with the vaccine, to stamp out the remaining reservoirs of transmission. Overall field effectiveness of nOPV2 in stopping paralytic outbreaks seems to be comparable with Sabin mOPV2, which is in line with clinical study findings. Most importantly, with lower risk of seeding new outbreaks compared to the Sabin mOPV2 experience as noted by field data so far, nOPV2 continues to demonstrate that it is an excellent tool to more sustainably stop outbreaks.

Q: What about safety? Are findings also in line with clinical studies?

A: Simona – Monitoring nOPV2’s safety has been one of our top priorities during the EUL period. We worked with the WHO pharmacovigilance team to set up an independent safety monitoring group to review the data and guide us in this regard. The Global Advisory Committee on Vaccine Safety’s nOPV2 sub-committee meets every six months to review data on nOPV2’s field performance. Because there has been such large-scale use of nOPV2, it has allowed us to generate a lot of data on safety from field use. So far, the sub-committee has reviewed safety data from over 370 million doses of nOPV2 administered and has not identified any safety red flags or concerns, noting that despite enhanced monitoring, the rate of adverse events following immunization with nOPV2 remains lower than published rates for other OPVs.

Q: And coming back to enhanced genetic stability compared to mOPV2, which is the primary reason this vaccine was developed, tell us more on how nOPV2 is performing on that front.

A: Ananda – An unprecedented level of effort has been put in place to monitor the genetic stability of the vaccine since rollout began, thanks to a dedicated group of experts led by US CDC and NIBSC UK and collaborators at the Global Polio Laboratory Network. Based on extensive analysis of whole genome sequencing data from isolates collected through sewage and clinical syndromic surveillance systems that are in place for polio, evidence supports nOPV2’s superior genetic stability compared to Sabin mOPV2, consistent with what was observed in pre-clinical and clinical studies.

nOPV2 vaccination in Republic of the Congo. ©WHO/AFRO

I must clarify that significantly higher genetic stability and lower risk of reversion to neurovirulence compared to Sabin mOPV2 does not mean nOPV2 has no risk of reversion. Thanks to a sensitive surveillance system, a handful of such instances of reversion to neurovirulent variants have been picked up in settings of persistently poor immunization coverage.

We’ve seen, very recently, evidence of reversion of public health significance in the Democratic Republic of the Congo (DRC), where two separate emergences of circulating variant poliovirus type 2 of nOPV2 origin have been detected, likely derived from double recombination events with human species C enteroviruses. Such recombination events and reversions resulted in seven paralytic cases in the DRC and neighboring Burundi.

In separate events, we also saw the detection of reverted and recombinant poliovirus variants of nOPV2 origin in two cases of paralytic polio in the Central African Republic in February 2023 and in an environmental sample collected in Uganda in February 2022. However, to date, circulation of these viruses in CAR and Uganda has not been established. These numbers are based on on-going assessment, and thus may change as GPEI continues the monitoring, laboratory work and field investigations.

With the much wider scale of nOPV2 use in areas of very limited background intestinal immunity for type 2 poliovirus, we may pick up more of these rare reversions going forward. It’s important to note, however, that overall trends of structural and functional changes [to the vaccine virus genome] of public health consequence remain dramatically lower with nOPV2 compared to prior experience with Sabin mOPV2. However, the program will continue to closely monitor the field-use data and interpret it with adequate nuance and contextualization.

Q: I suppose that campaign quality continues to be a key factor in reducing the risk of genetic reversion, then, even with nOPV2. Why is that?

A: Ananda: Enough children need to be reached enough times with vaccination efforts to stop virus circulation in areas with outbreaks. If children are missed, the virus causing the outbreaks will continue to circulate and spread. In addition, in such pockets of under- and un-vaccinated children who have sub-optimal intestinal immunity against poliovirus, the live attenuated or weakened strains of OPV – Sabin OPV and novel OPV included – can replicate and transmit long and sufficiently enough to acquire changes in their genetic structures, often through interactions (e.g. recombination events) with other enteroviruses in these settings to evolve into poliovirus variants that are structurally different from the vaccine strains, and that can potentially trigger new paralytic outbreaks. On the other hand, if OPV vaccination coverage is persistently high, meaning enough children are reached enough times, such rare risk of evolution into poliovirus variants of public health importance almost never arise.

Q: What needs to happen for nOPV2 to receive full licensure?

A: Ananda – This is already in process, thanks to the collaborative work of many partners, and continued guidance from the WHO prequalification (PQ) team and the Indonesian regulatory authority, BPOM. BioFarma is in the process of putting together the dossier for WHO Prequalification, that includes phase III study data that was led by PATH, data from other clinical studies such as one done in Bangladesh led by icddr,b in newborn infants, and additional information as required for this process. If this dossier is submitted by BioFarma by the end of March as per current targets, the expectation is to have a decision on WHO PQ and, therefore, full licensure of the vaccine before the end of 2023.

Q: What will happen to the key monitoring functions, for example, safety, genetic stability, etc.? Will these continue after PQ?

A: Simona – Like all vaccines, nOPV2 will continue to be monitored even after it is fully licensed, using the existing systems in countries, regions and at the global level. For example, countries will continue to implement acute flaccid paralysis and environmental surveillance, adverse events following immunization surveillance, and report any safety findings of concern to the Global Advisory Committee on Vaccine Safety. GPEI will also continue to monitor the vaccine’s genetic stability through the Global Polio Laboratory Network.

Q: Last question: How is work on nOPV 1 and 3 progressing?

A: Ananda – Phase I studies with nOPV type 1 and nOPV type 3 – both in development to combat the two other types of variant polioviruses – have been completed in the United States, led by PATH. The plan is to launch into phase II studies in 2023, and also to complete a preliminary assessment of the feasibility of a multivalent nOPV formulation and its subsequent clinical development. Overall, we expect to have phase II study or target population data on these vaccines by 2025-2026, per current projections. Availability of these novel vaccine choices should enhance our probability of success to achieve and sustain eradication of all forms of polioviruses so that our children can thrive and prosper in a polio-free world.

Opening of the 75th World Health Assembly – 22 May 2022. © WHO

May 2022, Geneva, Switzerland – Global public health leaders convening last week at the World Health Assembly called for urgent action to end polio once and for all before a unique window of opportunity closes for good.

Recent efforts have had a clear impact on the global epidemiology of poliovirus, with endemic wild poliovirus transmission at extremely low levels, with just Pakistan and Afghanistan remaining endemic, and efforts to curb circulating vaccine-derived polioviruses (cVDPVs) showing fruit. Steps have been taken towards securing the legacy of polio eradication systems and know-how, under the Strategic Action Plan for Polio Transition. But delegates cautioned that this ‘window of opportunity’ will not remain open indefinitely, as experts pointed to recent concerning developments such as new wild poliovirus cases confirmed in Pakistan (the first cases reported in 15 months), wild poliovirus detected in south-east Africa (the first on the African continent since 2016), and polio re-emergence in Ukraine and Israel.

“Worrying developments in recent months highlight how fragile this progress is,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General, addressing the Assembly. “These developments are tragic for the children affected and their families. But the reality is that in the final stages of an eradication effort, this is expected. This year, we have the real opportunity to halt wild poliovirus transmission. At the same time, we must respond faster and better to cVDPV outbreaks, to interrupt all transmission by end-2023.”

Success, however, depends on reaching remaining children who have not been immunized – the ‘zero-dose’ children at the heart of the Immunization Agenda 2030 (IA2030).

Such a need was identified at this month’s G7 joint Development and Health Ministers meeting in Berlin, Germany, where discussions focused on “supporting vaccine equity and pandemic preparedness in developing countries”. The meeting cautioned against letting global crises interfere with other development and public health priorities and urged continued support for existing efforts, including global polio eradication. Polio eradication is a clear and concrete example of the value of working in close integration with other public health and development efforts. Polio staff continue to contribute to the COVID-19 pandemic response and immunization recovery efforts, together with supporting the introduction and roll-out of COVID-19 vaccines.

Ministers and high-level delegations from 20 countries of regions affected by both WPV1 and cVDPV met with senior GPEI leaders for focused discussions on concrete ways to close the final chains of virus transmission. The meetings were chaired by Polio Oversight Board chair Dr Chris Elias from the Bill & Melinda Gates Foundation and respective WHO AFRO and EMRO Regional Directors, Dr Matshidiso Rebecca Moeti and Dr Ahmed Al-Mandhari. Key priorities were the importance of reaching zero-dose children, the challenges of complex emergencies and weak health systems, as well as the importance of inter-country coordination and collaboration.

Underscoring the urgency in giving the world one less infectious disease to worry about once and for all, WHO Director-General Dr Tedros issued a clear challenge to the Assembly: “For countries affected by polio, it is imperative that you reach every last child, and that you respond to vaccine-derived strains with the same urgency as you would to a wild strain. For countries that are now polio-free, it is crucial to accelerate efforts to use your polio assets and infrastructure to build stronger, more resilient health systems. And for all partners and donors, please help us seize the moment to raise predicable funding, for eradication and transition. I urge you to join us in Berlin this October at the pledging event* generously co-hosted by the Government of Germany. Your decision this week to support a stronger, sustainably financed WHO will enable us to sustain capacity in countries that are now polio-free and on the pathway to transition. Thank you all once again for your commitment to consigning polio to the history books.”

This call to action was echoed by Rotary International, the civil society partner of the global eradication effort. Addressing the Assembly on behalf of its 1.2 million members worldwide, Rotarian and Rotary Representative to the UN in Geneva, Professor Dr Pierre Hoffmeyer, concluded: “We call on all countries to address gaps in routine immunization levels and ensure robust surveillance to prevent further virus spread and avert future outbreaks.”

*In April 2022, GPEI partners, led by WHO Director-General, launched the ‘Investment Case for Polio Eradication’, the sister document to the Polio Eradication Strategy 2022-2026, which lays out the economic and humanitarian rationale for investing in a polio-free world, as well as the broader benefits of polio eradication. In October 2022, Germany will generously co-host a global pledging moment, giving the international development community the opportunity to publicly re-commit to this effort, including to support a stronger and sustainably-funded WHO, so that the organization can maintain its capacity to support countries in achieving and sustaining polio eradication, and continue to benefit broader public health efforts, including support for pandemic preparedness and response.

Children under 5 years vaccinated with nOPV2 in the Lakeside city of Aguegue (Oueme Department) © WHO/Benin

When it comes to stopping polio outbreaks, speed is everything. Rapid action within a specific window of time is critical. Malawi declared a public health emergency in February after uncovering a case of wild poliovirus type 1 (WPV1) – its first in 30 years. The country sprang into action, leading the charge in a multi-country vaccination response aiming to reach more than 23 million children in the sub-region with bivalent oral polio vaccine (bOPV). Three months later, neighbouring Mozambique which has been part of the same response, declared its own emergency after the virus paralyzed a child on its home soil. The country is doubling down on efforts to protect its children.

The nimble actions of the south-eastern African nations have been lauded by the GPEI as examples of what must be done to effectively quash circulation of the highly infectious poliovirus.

“Indeed Malawi has moved quickly; thus far we haven’t seen further detection of WPV1 in the country,” said Dr Modjirom Ndoutabe, Polio Programme Coordinator a.i., WHO AFRO. “It is important that further campaign rounds are carried out as planned and reach all targeted children to boost immunity in Malawi and its surrounding countries, and we’re working with governments to maintain heightened surveillance sensitivity so that we can closely track this virus through this outbreak period,” he added.

“What we’ve seen in Malawi and Mozambique following their detections, but also Tanzania, Zambia and Zimbabwe engaged in the response is encouraging. The need for speed in recognizing and communicating the public health threat and conducting quality vaccination campaigns to protect children cannot be understated,” said Aidan O’Leary, Director of WHO’s polio eradication programme.

Addressing a dual threat

Wild poliovirus is not the only form of poliovirus facing the African Region, or the world at large. Outbreaks of circulating vaccine-derived poliovirus (cVDPV) continue to pose an equally menacing threat to countries. Through rollout of a new vaccine to counter the most prevalent form of these outbreaks, cVDPV2, transmission has been stopped in the majority of countries that have deployed the tool. Additionally, a significant number of outbreaks have been recently closed following use of the traditional monovalent oral polio vaccine type 2 (mOPV2).

“WHO African Region’s Rapid Response Team (for polio) recently conducted a review of polio outbreaks over the past two years, looking at time passed since last virus detections in infected countries, surveillance quality indicators, and immunization response quality and immunity profiles of populations. I am pleased to say that 32 separate emergences of cVDPV in the Region have been declared closed across 13 countries in Africa,” said Dr Ndoutabe.

“Closure of these cVDPV outbreaks is testament to the work that has gone into achieving the high levels of vaccination coverage needed to stop transmission, and efforts to sharpen surveillance for the disease. It also illustrates the effectiveness of the vaccines we have to do the job,” said O’Leary. “Regardless of which tool is used, GPEI urges all countries affected by poliovirus to act without delay, in line with timelines contained in its SOPs for outbreak response. We must ensure that actions are commensurate with the public health emergency that polio is, despite challenges,” he reiterated.

Both viruses found in Malawi and Mozambique stem from WPV1 that was circulating in endemic Pakistan in 2019 and 2020. Though wild poliovirus cases are dwindling – currently at the lowest level in history – the fresh detections underscore both the danger of importation and the need to finish the job.

In this two-part video series, we chat with Dr Ananda Bandyopadhyay, Deputy Director of Polio Technology, Research & Analytics, BMGF, about the new tool in GPEI’s kit to combat cVDPV2: novel oral polio vaccine type 2 (nOPV2).

11 October 2021

Following careful review of safety and genetic stability data from mass immunization campaigns conducted with the novel oral polio vaccine type 2 (nOPV2), the Strategic Advisory Group of Experts on immunization (SAGE) today endorsed the transition to the next use phase for the vaccine. WHO’s independent Global Advisory Committee on Vaccine Safety (GACVS) and SAGE confirmed that there were no major safety concerns associated with nOPV2 after reviewing data from campaigns that used more than 65 million doses in Nigeria, Liberia, Congo and Benin earlier this year. Rollout of nOPV2 began in March and to date approximately 100 million doses have been administered to children across seven countries.

This decision marks the end of the vaccine’s initial use period and the removal of certain use criteria for countries affected by circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks. It means that more countries will be eligible to use the vaccine under its WHO Emergency Use Listing (EUL) recommendation, once verified for use and as supply allows.

“The move is a positive and welcome advancement as GPEI and countries strive to bring cVDPV2 outbreaks to an end, and sees the achievement of a milestone outlined in goal 2 of our strategic plan: the goal to stop cVDPV2,” commented Aidan O’Leary, WHO’s director of polio eradication. “Not only does the decision inspire further confidence in nOPV2 as a safe and effective tool, it will facilitate a smoother preparedness process for countries looking to use the vaccine in the future,” he added.

“We are very pleased with the SAGE’s endorsement of transitioning nOPV2 to the next rollout phase. Progress like this is a result of strong partnerships at every level and we must continue forging forward together, using innovative tools like nOPV2, to reach every last child and end all forms of polio for good,” said Akhil Iyer, the UNICEF Director of Polio Eradication.

Ananda Bandyopadhyay, deputy director from the Bill & Melinda Gates Foundation and co-lead of GPEI’s nOPV2 Working Group stated, “Today is an important milestone in the road to polio eradication. Innovation has always been key to progress, and this tool – the first vaccine ever to be approved under WHO’s EUL pathway – is a shining example of how the GPEI responds to challenges, but the work is far from over.” BMGF is a core partner in GPEI and has funded the development of nOPV2 from its inception.

Requirements for rollout

Prior to this transition, countries were required to meet an additional set of strict criteria to use nOPV2 during its initial use period. These were developed by GPEI and endorsed by SAGE to allow for even closer monitoring of nOPV2’s performance during its introductory phase and early large-scale uses. While countries no longer need to meet these initial use protocols, use of nOPV2 remains subject to specific post-deployment requirements under EUL, such as monitoring for safety and effectiveness.

“As we move forward into the next phase of the vaccine’s rollout, countries will still need to meet special use requirements, but they will be less onerous,” said Simona Zipursky, WHO co-lead of the GPEI’s nOPV2 Working Group. “GPEI will continue to work with all countries who wish to roll out nOPV2 to help them meet these remaining criteria,” she added.

Optimal response with available vaccine

In addition to those who have already rolled out the new tool, 16 other countries are also verified as ready to use nOPV2 by GPEI and a further 17 are in the midst of preparations. More nOPV2 campaigns are due to launch later this year, however, supply of the vaccine is limited.

Active cVDPV2 outbreaks are ongoing in more than 20 countries across Africa and Asia and there have been recent detections of the virus in Europe. COVID-19 has impacted production of the vaccine, including by limiting supplies, available personnel and manufacturer capacity. GPEI is working with nOPV2’s manufacturer, Bio Farma, to increase supply as soon as possible and is accelerating efforts to bring a second manufacturer online. A GPEI prioritization framework will guide distribution of nOPV2 for the immediate term, until supply is increased.

“We are seeing sharp rises in demand for nOPV2, which is testament to the vaccine’s field performance, and we are working to increase supply as quickly as feasible,” said O’Leary. “We must be very clear though, that outside of nOPV2, there is no shortage of effective type-2 containing oral polio vaccines, and countries should not delay in responding to an outbreak. In line with SAGE’s guidance they should respond rapidly with whichever of the vaccines (mOPV2/nOPV2) is available to them,” he said.

With nOPV2 not yet WHO-prequalified, monovalent oral polio vaccine type 2 (mOPV2) ̶ nOPV2’s counterpart and close relative ̶ remains available to countries for outbreak response. The vaccine has a track record of successfully stopping cVDPV2 transmission and from 2019 to 2020, nearly 80% of outbreaks were closed following just two rounds of immunization. Trivalent oral polio vaccine (tOPV), containing all three vaccine serotypes, may be a more appropriate tool in situations where there is co-circulation of wild polio virus type 1 (WPV1) and cVDPV2.

“All OPVs can stop outbreaks,” said O’Leary. “Regardless of which vaccine is used, the key for any successful [outbreak] response is achieving high levels of vaccination coverage and quickly. That is what we need to remain mindful of and achieve. nOPV2 is only one of the effective vaccines in our toolkit and GPEI will continue to support countries to respond as rapidly as possible to outbreaks, as per the SAGE guidance.”

Next steps for nOPV2 development

Polio remains a Public Health Emergency of International Concern (PHEIC) under International Health Regulations, enabling nOPV2’s continued use through EUL. Field data collection and analyses will be ongoing to support the vaccine’s prequalification and full licensing, expected in 2023. Among other studies, a phase III clinical trial is currently underway in the Gambia.

GENEVA, 10 June 2021 – Today, the Global Polio Eradication Initiative (GPEI) will launch the Polio Eradication Strategy 2022-2026: Delivering on a Promise at a virtual event, to overcome the remaining challenges to ending polio, including setbacks caused by COVID-19. While polio cases have fallen 99.9% since 1988, polio remains a Public Health Emergency of International Concern (PHEIC) and persistent barriers to reaching every child with polio vaccines and the pandemic have contributed to an increase in polio cases. Last year, 1226 cases of all forms of polio were recorded compared to 138 in 2018.

In 2020, the GPEI paused polio door-to-door campaigns for four months to protect communities from the spread of COVID-19 and contributed up to 30,000 programme staff and over $100 million in polio resources to support pandemic response in almost 50 countries.

Leaders from the two countries yet to interrupt wild polio transmission—Pakistan and Afghanistan—called for renewed global solidarity and the continued resources necessary to eradicate this vaccine-preventable disease. They committed to strengthening their partnership with GPEI to improve vaccination campaigns and engagement with communities at high risk of polio.

Dr Faisal Sultan, Special Assistant to the Prime Minister of Pakistan on Health, said, “We are already hard at work with our GPEI partners to address the final barriers to ending polio in Pakistan, particularly through strengthening vaccination campaigns and our engagement with high-risk communities. Eradication remains a top health priority and Pakistan is committed to fully implementing the new GPEI strategy. We look forward to working with international partners to achieve a polio-free world.”

The 2022-2026 Strategy underscores the urgency of getting eradication efforts back on track and offers a comprehensive set of actions that will position the GPEI to achieve a polio-free world. These actions, many of which are underway in 2021, include:

further integrating polio activities with essential health services—including routine immunization—and building closer partnerships with high-risk communities to co-design immunization events and better meet their health needs, particularly in Pakistan and Afghanistan;
applying a gender equality lens to the implementation of programme activities, recognizing the importance of female workers to build community trust and improve vaccine acceptance;
strengthening advocacy to urge greater accountability and ownership of the program at all levels, including enhanced performance measurement and engagement with new partners, such as the new Eastern Mediterranean Regional Subcommittee on Polio Eradication and Outbreaks; and,
implementing innovative new tools, such as digital payments to frontline health workers, to further improve the impact and efficiency of polio campaigns.

“With this new Strategy, the GPEI has clearly outlined how to overcome the final barriers to securing a polio-free world and improve the health and wellbeing of communities for generations to come,” said Dr Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization and member of the Polio Oversight Board. “But to succeed, we urgently need renewed political and financial commitments from governments and donors. Polio eradication is at a pivotal moment. It is important we capitalise on the momentum of the new Strategy and make history together by ending this disease.”

Dr Wahid Majrooh, Acting Minister of Public Health for Afghanistan, said, “Afghanistan is fully committed to implementing the new GPEI strategic plan and eradicating polio from its borders. Together we have come so far. Let us take this final step together and make the dream of a polio-free world a reality.”

In addition to eradicating wild polio, GPEI will strengthen efforts to stop outbreaks of circulating vaccine-derived poliovirus (cVDPV) that continue to spread in under-immunized communities across Africa and Asia. This includes deploying proven tactics used against wild polio, improving outbreak response and streamlining management through the launch of new global and regional rapid response teams and broadening the use of a promising new tool – novel oral polio vaccine type 2 (nOPV2) – to combat type 2 cVDPVs, the most prominent variant.

H.E. Félix Tshisekedi, President of the Democratic Republic of the Congo, said “As Chair of the African Union, I call on every government to increase their commitment to protecting the gains of our monumental efforts and finishing the job against polio in Africa. Only then, we will be able to say we delivered on our promise of a safer, healthier future for all our children.”

Select countries began using nOPV2 in March of this year after WHO issued an Emergency Use Listing recommendation for the vaccine last November. Clinical trials have shown that nOPV2 is safe and effective against type 2 polio, while having the potential to stop cVDPV2 outbreaks in a more sustainable way compared to the existing type 2 oral polio vaccine.

In addition to supporting the COVID-19 response, polio assets and infrastructure have historically helped tackle the emergence of health crises in several countries around the world, including the Ebola outbreak in Nigeria in 2014. Without the support needed for the new GPEI Strategy, there is a risk not only that polio could resurge, but also that countries will be more vulnerable to future health threats.

Additional quotes:

Henrietta Fore, Executive Director, UNICEF: “We will not allow the fight against one deadly disease to cause us to lose ground in the fight against polio and other childhood diseases. Renewed government and donor support will enable us to reach and immunize over 400 million children against polio every year and ensure that no family has to live with the fear of their child being paralyzed by this deadly disease ever again.”

Rochelle P. Walensky, MD, MPH, Director, CDC: “As the GPEI’s support for the COVID-19 response shows, polio infrastructure is vital to helping countries tackle emerging health threats. The U.S. CDC is committed to achieving polio eradication and delivering, through the GPEI’s new strategy, on the promise we made to protect the world’s children. To improve health equity, we must ensure that polio assets are secured and that countries are increasing their immunization coverage through integrated service delivery and demand for vaccines.”

Seth Berkley, CEO, Gavi, the Vaccine Alliance: “Polio eradication is possible and essential. Through the increased integration of polio activities with essential immunization and health services, including our joint work to extend the health system to reach “zero-dose” children and missed communities with all routine vaccines, we believe that we can better meet the needs of high-risk communities and secure a polio-free world together.”

Mike McGovern, Chair, Rotary’s International PolioPlus Committee: “More than 19 million people are walking today who would have otherwise been paralysed by polio, thanks to the incredible progress we’ve made in protecting children with polio vaccines since 1988. When Rotary helped found the GPEI, we made a commitment to ensure that no child or family should live in fear of polio ever again. We are committed to delivering on this promise and urge governments and donors to help us achieve a polio-free world.”

Chris Elias, President, Global Development, Bill & Melinda Gates Foundation: “After setbacks in recent years, and indications that some donors may reduce funding to the GPEI, there has never been a more important moment than right now in the history of polio eradication. With adequate support for the new strategy, we can secure a world where no child will be paralyzed by polio ever again and we urge all donors to stay committed and consign this disease to history.”

Media contacts:

Oliver Rosenbauer
Communications Officer, World Health Organization
Email: rosenbauero@who.int
Tel: +41 79 500 6536

Ben Winkel,
Communications Manager, Global Health Strategies
Email: bwinkel@globalhealthstrategies.com
Tel: +1 323 382 2290

Note for editors:

The Global Polio Eradication Initiative is a public-private partnership led by national governments with six core partners – the World Health Organization (WHO), Rotary International, the US Centers for Disease Control and Prevention (CDC), UNICEF, the Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.

Watch launch the event.

Little girl receiving polio drops © WHO/AFRO

13 March 2021, Brazzaville – To rapidly and sustainably stop outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2) in African countries, a modified vaccine, known as novel oral polio vaccine type 2 (nOPV2) is now being rolled out.

Last year, on 25 August 2020, Africa made history with the African Region Certification Commission for Polio Eradication independently certifying that the Region was free of wild poliovirus. This is the second disease to be kicked out of Africa after smallpox more than 40 years ago.

This achievement is remarkable, considering that in the 1990s wild poliovirus paralysed more than 75,000 African children every single year – a situation that prompted Nelson Mandela in 1996, joined by Rotary International and other partners, to issue a stark call to action: Kick Polio Out of Africa!

All strains of wild poliovirus have now been interrupted in the continent. The last case of wild poliovirus was in August 2016.

However, this tremendous progress remains an unfinished success story. Although Africa is free of wild poliovirus, countries continue to be affected by another form of the virus, known as circulating vaccine-derived poliovirus type 2 (cVDPV2). Such strains are rare, but can occur in under-immunized communities with limited access to safe water and sanitation.

Populations that are adequately immunized are protected from both wild and vaccine-derived strains of poliovirus. However, because of gaps in immunization coverage across Africa, 20 countries have been affected by cVDPV2 outbreaks since 2018.

Now, intensified efforts are being launched to finish polio once and for all, to ensure no child in Africa will ever be paralysed by any strain of this virus.

The novel OPV2 vaccine has been in development since 2011, and in November 2020, WHO’s Prequalification Team issued an emergency use listing (EUL) recommendation enabling initial roll-out in countries affected by cVDPV2 outbreaks. Soon after the issuance of the EUL, the WHO Regional Director for Africa, Dr Matshidiso Moeti, advocated to countries to use this additional tool to stop all forms of polio in Africa.

For nOPV2 to be deployed and used under the EUL, special readiness requirements and criteria need to be met. The Polio Rapid Response Team at WHO’s Regional Office for Africa, in close coordination with other Global Polio Eradication Initiative partners, has been working intensely with countries and partners across the continent to respond to outbreaks of cVDPV2 and prepare for the roll out of nOPV2.

As countries in the Region gear up to roll out this new tool for outbreak response, with WHO’s support they are developing supply, demand and deployment plans; ensuring expedited pathways for national regulatory approvals; enhancing surveillance and laboratory capacity; investing in meeting cold-chain capacity and vaccine management requirements; ensuring vaccine safety monitoring and follow-up mechanisms are in place; and developing communication plans and engaging communities to enhance understanding of the vaccine and risks posed by cVDPV2.

These preparations continue even amidst the COVID-19 pandemic, and the existing polio eradication infrastructure has been instrumental in preparing for the nOPV2 vaccine as well as more broadly supporting COVID-19 response efforts across the continent.

Years of extensive development and preparations are now about to pay off, as nOPV2 will now be utilized for outbreak response. “This is tremendous news for Africa’s polio eradication effort, and in particular for Africa’s children who are currently at risk of lifelong paralysis due to circulating vaccine-derived poliovirus,” said Dr Moeti. “This tool can stop cVDPV2 but only if it reaches all at-risk children. We must apply the lessons from the decades of action to kick wild polio out of Africa. This will require the collective action of political leaders, traditional and religious leaders, public health experts, partners, donors, frontline health workers and of course parents and caregivers. Together, we can protect all African children from all forms of this virus.”

More information on nOPV2.

Related news

13 Novembre 2020 – Aujourd’hui, le programme de préqualification de l’Organisation mondiale de la Santé (OMS) a émis une recommandation d’autorisation d’utilisation d’urgence au titre du protocole EUL pour un nouveau vaccin antipoliomyélitique oral de type 2 (nVPO2). Le déploiement du vaccin sera ainsi autorisé pour une utilisation initiale limitée dans les pays touchés par des flambées de poliovirus circulant dérivé d’une souche vaccinale de type 2 (PVDVc2).

L’émission de cette recommandation au titre du protocole EUL pour le nVPO2 vient au terme de plusieurs mois d’analyse rigoureuse des données issues d’essais cliniques qui ont démontré l’innocuité du vaccin et une protection contre la poliomyélite comparable à celle fournie par le VPO monovalent de type 2 (VPOm2) actuellement utilisé.

Le nVPO2 est une version modifiée du VPOm2, mis au point depuis près de dix ans grâce à la collaboration d’un vaste réseau d’experts mondiaux.^[1] Outre son innocuité et son efficacité, les essais cliniques montrent que ce vaccin est génétiquement plus stable que le VPOm2, ce qui réduit nettement la probabilité qu’il retrouve une forme pouvant entraîner une paralysie dans les milieux présentant un faible niveau d’immunité. Par conséquent, le nVPO2 réduit le risque de voir apparaître de nouvelles flambées de PVDVc2, même si le VPOm2 demeure un vaccin sûr et efficace qui protège contre la poliomyélite et qui a permis d’empêcher des flambées de PVDVc2 par le passé.

Qu’est qu’une autorisation d’utilisation d’urgence ?

La procédure EUL de l’OMS, anciennement connue sous le nom de procédure d’évaluation et d’homologation en situation d’urgence de l’OMS (Emergency Use Listing, EUL), a été créée pour évaluer et répertorier les nouveaux vaccins, traitements et produits diagnostiques qui ne sont pas encore homologués afin qu’ils puissent être utilisés de façon précoce et ciblée en réponse à une urgence de santé publique de portée internationale (USPPI).

Ce mécanisme a déjà été utilisé avec succès pour accélérer la mise à disposition de produits diagnostiques pour les virus Ebola et Zika et, fin septembre, une autorisation d’utilisation d’urgence au titre du protocole EUL a été émise pour un test de diagnostic rapide de l’antigène de la COVID-19 qui donne des résultats en 30 minutes.

Pour qu’un produit reçoive une recommandation d’utilisation au titre du protocole EUL, l’OMS et des experts indépendants examinent les données cliniques existantes afin de déterminer son innocuité, sa qualité et son efficacité, et la décision d’émettre une recommandation est fondée sur une évaluation approfondie des avantages et des risques au vu de l’urgence de santé publique.

Pendant toute la durée d’utilisation d’un produit au titre du protocole EUL, on continue à recueillir des données et à les suivre de près afin de déterminer si ce produit peut recevoir une autorisation d’utilisation d’urgence au titre du protocole EUL.

Pourquoi le protocole EUL est-il utilisé pour le nVPO2 ?

Compte tenu des situations d’urgence actuelles concernant le PVDVc2 en Afrique et en Asie et du fait que la poliomyélite est considérée depuis 2014 comme une urgence de santé publique de portée internationale (USPPI), au mois de février, le Conseil exécutif de l’OMS a prié instamment les États Membres d’accélérer les procédures d’autorisation de l’importation et de l’utilisation du nVPO2 au titre du protocole EUL au vu des résultats prometteurs de ce vaccin dans la lutte contre le PVDVc2.

Les flambées de PVDVc2 se produisent lorsque la souche affaiblie du poliovirus contenue dans le vaccin antipoliomyélitique oral (VPO) peut se propager au sein de populations sous-vaccinées pendant une période prolongée et retrouver une forme pouvant entraîner une paralysie. L’année dernière, il y a eu 366 cas de PVDVc2 dans le monde. Au cours des dix premiers mois de 2020, on a recensé 588 cas (données au 28 octobre 2020).

Outre la décision du Conseil exécutif, le Groupe stratégique consultatif d’experts (SAGE) sur la vaccination a approuvé dans son principe un cadre définissant les critères d’une utilisation initiale pour permettre le déploiement rapide et ciblé du nVPO2. À la suite de sa réunion du 5 au 7 octobre, le SAGE a également approuvé, sur le principe, que le nVPO2 devienne le vaccin de choix pour lutter contre les flambées de PVDVc2, une fois que l’examen de la période initiale d’utilisation sera terminé et que toutes les conditions d’utilisation de ce nouveau vaccin seront remplies.

Des études cliniques sur le nVPO2, menées en Belgique et au Panama, ont montré que le vaccin était sûr et efficace pour protéger contre la poliomyélite, et qu’il présentait moins de risque de retrouver une forme pouvant entraîner une paralysie dans des populations sous-vaccinées.

Au cours des six derniers mois, le programme de préqualification de l’OMS a minutieusement analysé les données émanant de ces études afin de déterminer si le nVPO2 répondait aux exigences du protocole EUL. Grâce à la recommandation au titre de ce protocole, le nVPO2 constitue désormais un moyen supplémentaire de la Stratégie de lutte contre le PVDVc2 de l’IMEP.

Quelle est la période d’utilisation initiale du nVPO2 ?

Comme le précise le cadre approuvé par le SAGE, la période d’utilisation initiale durera environ trois mois après la première utilisation du nVPO2 au titre du protocole EUL, et ce vaccin sera déployé de manière mesurée dans la lutte contre les flambées de PVDVc2.

L’IMEP travaille étroitement avec les pays touchés par des flambées de PVDVc2 afin de déterminer où le nVPO2 peut être utilisé pendant la période initiale. Cette décision s’appuiera notamment sur la situation épidémiologique actuelle et sur la capacité du pays à mener la surveillance renforcée requise en termes d’innocuité et d’efficacité du nVPO2 pendant son déploiement.

Il est important de noter que toute décision d’utiliser le nVPO2 sera prise par le pays et soumise à l’accord des responsables concernés dans le pays et des autorités de réglementation nationales. Le VPOm2 restera disponible pour faire face aux flambées dans les pays qui ne répondent pas aux critères d’une utilisation initiale ou qui décident de ne pas utiliser le nVPO2 initialement.

L’utilisation initiale du nVPO2 devrait avoir lieu environ cinq à huit semaines après la publication de la recommandation d’utilisation au titre du protocole EUL, en tenant compte des processus réglementaires et des approbations définitifs, de l’achat des vaccins, de l’expédition et de l’état de préparation du pays. L’IMEP continue de travailler en étroite collaboration avec les pays à haut risque, en les aidant à se préparer à utiliser le nVPO2.

Perspectives d’avenir

On continuera à recueillir des données sur le nVPO2 pendant la période d’utilisation initiale, en plus des études en cours et de celles qui seront menées prochainement.

Parallèlement à l’utilisation initiale du nVPO2, l’IMEP poursuivra la mise en œuvre des autres volets de sa stratégie globale de lutte contre les flambées de PVDVc2. Cette stratégie consiste notamment à optimiser la riposte aux flambées en utilisant le VPOm2, à renforcer la vaccination systématique avec le vaccin antipoliomyélitique inactivé dans les zones à haut risque et à veiller à ce que les stocks de VPO soient suffisants pour que chaque enfant puisse en bénéficier.

En savoir plus sur le développement de nVPO2

^[1] Le nVPO2 a été mis au point grâce à un partenariat mondial réunissant de multiples agences et experts internes et externes à l’Initiative mondiale pour l’éradication de la poliomyélite (IMEP). Il s’agit notamment de Bio Farma, de l’Université d’Anvers, de la FIDEC (Fighting Infectious Diseases in Emerging Countries), du NIBSC (National Institute for Biological Standards and Control), de l’UCSF (University of California San Francisco), des CDC (Centers for Disease Control and Prevention des États-Unis), de PATH et de la Fondation Bill et Melinda Gates.