The Global Polio Eradication Initiative in collaboration with Gavi, The Vaccine Alliance, has successfully achieved the global goal, set in 2013, of 126 Oral Polio Vaccine (OPV)-using countries incorporating at least one dose of IPV in their immunization activities. The last two remaining countries, Mongolia and Zimbabwe, introduced IPV in their immunization programmes in April 2019.

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After concerted efforts spanning decades, polio eradication efforts are in the homestretch and experts are advising how to fast-track the last mile.

The SAGE convened in Geneva from 2-4 April 2019 to discuss all things related to vaccines and immunizations, including poliovirus and the global eradication efforts around it. SAGE reviewed the latest global polio epidemiology, the new Global Polio Eradication Endgame Strategy 2019-2023, and what the post-eradication world could look like.

Interruption of wild poliovirus continues to be a priority for the success of GPEI at the latest SAGE meeting. ©WHO
Interruption of wild poliovirus continues to be a priority for the success of GPEI at the latest SAGE meeting. ©WHO

Double down and escalate the fight to end wild poliovirus

While SAGE noted the achievements and the progress of the Global Polio Eradication Initiative—reducing the incidence of polio by 99%, absence of wild polio virus type 3 cases, and evidence of Nigeria being wild poliovirus free for over two years—the group displayed cautious optimism about meeting the timeline set out for global eradication of wild poliovirus.

The remaining challenges to fill vaccination coverage gaps—including restricted access, socio-political challenges, and large mobile populations—complicate the efforts to rid the world of poliovirus. However, the GPEI has developed a clear-cut five- year plan to secure a decisive win, the GPEI Polio Endgame Strategy 2019-2023, developed in broad consultation with stakeholders, including SAGE members.

Inactivated Polio Vaccine (IPV)—progress in roll-out continues

From the public health standpoint, Inactivated Polio Vaccine (IPV) can be used indefinitely even after polio eradication. As of April 2019, all 33 countries which had not yet introduced IPV into their routine immunization activities have now done so.

The projected IPV supply is thought to be sufficient enough for the introduction of a two-dose IPV schedule in all countries by 2022, and to catch-up all children missed due to earlier supply shortages, by 2020/2021.

Guidelines Endorsed

As per SAGE recommendations made in October 2016, GPEI developed guidelines for poliovirus surveillance among persons with primary immunodeficiency. After reviewing the guidelines, the SAGE endorsed the guidelines for implementation in high priority countries.

The meeting report will be published in the WHO Weekly Epidemiological Record by May 2019.

Strategic Advisory Group of Experts

The Strategic Advisory Group of Experts (SAGE) on Immunization was established by the Director-General of the World Health Organization in 1999 to provide guidance on the work of WHO. SAGE is the principal advisory group to WHO for vaccines and immunization. It is charged with advising WHO on overall global policies and strategies, ranging from vaccines and technology, research and development, to delivery of immunization and its linkages with other health interventions. SAGE is concerned not just with childhood vaccines and immunization, but all vaccine-preventable diseases.

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A child is vaccinated with fIPV during a campaign in Hyderabad, India. © WHO/Harish Verma
A child is vaccinated with fIPV during a campaign in Hyderabad, India. © WHO/Harish Verma

A new study published this month in the Journal of Infectious Diseases has shown that a single dose of fractional dose inactivated poliovirus vaccine (fIPV) boosts mucosal immunity to a similar degree as a full dose of IPV, in children previously immunized with oral polio vaccine (OPV). During the current IPV shortage, this vaccine is not recommended for outbreak response, however, if it is used, then this finding provides further evidence in support of fIPV rather than full dose IPV at a time of IPV global supply shortage.

The efficacy of fIPV in boosting humoral immunity (offering individual protection against paralytic disease) in comparison to full-dose IPV had already been established, and this dose-sparing approach for routine immunization programmes was subsequently recommended by the Strategic Advisory Group of Experts on immunization (SAGE). Thanks to an increasing number of countries adopting this approach, including Bangladesh, India, Nepal, Sri Lanka, Cuba and Ecuador, there have been significant improvements in the global supply of this vaccine.

These latest findings show that fIPV also has a significant role to play in outbreak response. Mucosal immunity is needed to interrupt person-to-person spread of the virus in a community, so is a critical factor in outbreak response. Used in conjunction with OPV, even a single dose of this formulation could now play a key role in such settings, by rapidly boosting mucosal immunity at a similar level to a full-dose IPV while using a fifth of the vaccine amount. This has clear benefits both on cost and supply.

“Globally, demand for IPV is high and the supply is constrained,” commented Dr Tahir Yousafzai from Aga Khan University in Karachi, Pakistan. “As polio eradication is gradually eliminating OPV, countries will eventually rely solely on IPV, further increasing demand. Fractional IPV can stretch the limited IPV supply and provide similar humoral and mucosal protection when compared to full-dose IPV in children vaccinated with OPV. In addition, it will play an important role in stopping poliovirus transmission, and hence help in the eradication of wild poliovirus and circulating vaccine-derived poliovirus.”

For the post-polio era, the Global Polio Eradication Initiative and its partners are continuing to explore new IPV approaches to ensure an affordable and sustainable supply following global polio eradication, including through the use of IPV vaccine manufactured from Sabin strains or non-infectious materials such as virus-like particles.

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A child receives an IPV (inactivated poliovirus vaccine) vaccination during routine immunization activities in Bangladesh. © Gavi
A child receives an IPV (inactivated poliovirus vaccine) vaccination during routine immunization activities in Bangladesh. © Gavi

In the fight against the virus, two important tools are used to help prevent polio – two safe, effective vaccines. Only through full funding of these vaccines can worldwide immunity be achieved, and the virus eradicated.

Redoubling commitment towards this goal, last week, Gavi, The Vaccine Alliance, approve core funding for the inactivated poliovirus vaccine (IPV) for 2019 and 2020, to continue work to end polio, and protect every child.

Announcing this support, Gavi Board Chair Dr Ngozi Okonjo-Iweala said, “Polio will remain a threat until every child is protected against this crippling disease. That is why the vaccination of every child is the corner stone of the polio eradication effort. Introducing IPV to all countries to interrupt polio transmission and maintain zero cases represents an unprecedented push, and Gavi is proud to be part of it.”

Since 2013, the Gavi Board has supported IPV in all 70 Gavi-supported countries, through a dedicated funding stream financed by the Global Polio Eradication Initiative (GPEI) budget. Responding to continued wild poliovirus circulation in 2018, this most recent Gavi support represents an additional contribution, which will help ensure that the programme can continue its valuable work to protect every child worldwide.

The Gavi Board also approved an exceptional extension of support for Nigeria up to 2028, to help reach over 4.3 million under-immunized children in the country, who remain at risk of vaccine-preventable diseases including polio.

Michel Zaffran, Director of the Polio Eradication Programme at the World Health Organization, extended his thanks to the Gavi Board for their generous contribution, saying, “GPEI and Gavi are committing to work closer together than ever before, and take one more step towards the immunization of all children, to deliver and to sustain a polio-free world.”

© Sweden National Authority for Containment
© Sweden National Authority for Containment

A vaccine manufacturer in Stockholm has taken the first step towards becoming a certified Poliovirus Essential Facility (PEF), leading the charge in global efforts to safely and securely contain type-2 poliovirus. This facility has been awarded a Certificate of Participation co-signed by the National Authority for Containment (NAC) in Sweden and the Global Commission for the Certification of Poliomyelitis Eradication (GCC). The Certificate is the first of its kind to be issued, indicating formal engagement in the global containment certification process.

Wild poliovirus type-2 was declared eradicated by the GCC in September 2015, however, there is risk of the virus resurging. Following the removal of the type-2 component from oral polio vaccine (OPV) and the discontinuation of type-2 containing OPV from routine use in April 2016, countries around the world have been asked to safely and securely destroy their type-2 polio samples. As a further precaution, countries continue to immunize against type 2 polioviruses with inactivated polio vaccine. For facilities needing to retain the virus for vaccine production or for critical research, stringent containment measures need to be followed. The first step is getting a Certificate of Participation.

Handling of infectious virus. © Sweden National Authority for Containment
Handling of infectious virus. © Sweden National Authority for Containment

“We are pleased to see Sweden leading the way in demonstrating conforming with the processes to minimize the risk of releasing type-2 poliovirus into the environment. Participation in the Containment Certification Scheme shows that both the facility and the host country are serious about taking on and implementing the safeguard measures necessary to become a PEF,” said Prof. David Salisbury, Chair of the GCC and of the Commission’s European regional body.

“Handling and storing an eradicated pathogen is a risk and responsibility – a leak or breach could have devastating consequences,” said Michel Zaffran, Director of Polio Eradication at the World Health Organization. “We commend Sweden for its commitment towards ensuring safety standards are met and protocols are in place to help minimize risk, and for paving the road for the containment certification process,” he said.

“The issuance of a Certification of Participation formally engages a designated PEF in the containment process. Provided that the facility meets the requirements outlined in Global Action Plan III for the containment of polioviruses (GAPIII) within given time frames, it can then progress to achieving an Interim Certificate of Containment and finally, a full Certificate of Containment to become an accredited PEF,” said Prof. Salisbury. “Countries planning to retain type-2 poliovirus will need to establish their NACs as soon as possible, and by no later than the end of 2018. The GCC urges all countries that plan to have PEFs to get the ball rolling in this process,” he said.

Since April 2016, most facilities around the world have opted to destroy their type-2 poliovirus materials rather than contain them. Twenty-nine countries, however, plan to continue to handle and store their materials in 92 designated PEFs.

WHO will propose a resolution for consideration by the World Health Assembly in May to seek international consensus on accelerating containment efforts globally.

Ondrej Mach of the WHO polio research team discusses why new inactivated polio vaccine solutions are needed for the post-eradication era. Why are we developing entirely new vaccines for a disease which will no longer exist?

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140th session of WHO Executive Board, Geneva, Switzerland. Photo: WHO/C.Black

27 January 2017, Geneva, Switzerland – Ministries of health gathering at this week’s Executive Board of the World Health Organization (WHO) reviewed the latest global poliovirus epidemiology and concluded that the world has never had a better chance to complete the job. Amid discussions on Ebola, Zika and pre-elections for the new WHO Director-General, delegates stressed the urgent need to secure a lasting polio-free world, by fully implementing the Global Polio Eradication Initiative (GPEI) Polio Eradication Endgame Strategic Plan.

Endemic polio is now restricted to a handful of areas of Pakistan, Afghanistan and Nigeria, all of which are implementing regionally-coordinated emergency plans to reach and vaccinate the remaining pockets of under-immunized children.

Despite more children being reached in these traditional ‘reservoir’ areas for the virus, delegates cautioned that risks remained, as underscored by the detection of polio cases in Borno state of Nigeria, the first in two years anywhere in Africa.  Countries are now focusing on making sure there are no surveillance gaps at a subnational level so that virus cannot circulate undetected, while working to increase population immunity levels.

Delegates commended the successful global switch from trivalent oral polio vaccine (OPV) to bivalent OPV in 2016, and emphasized that strong surveillance to detect any type 2 poliovirus from any source is now critical.  A global stockpile of monovalent OPV type 2 (mOPV2) remains on hand for potential response as needed.  A critical global supply shortage of inactivated polio vaccine (IPV) continues to pose a risk, but is being managed by prioritizing available supply to high-risk areas and implementing new measures to stretch available supply, notably use of fractional IPV, as recommended by the Strategic Advisory Group of Experts on immunization (SAGE).

At the same time, countries expressed appreciation at the ongoing efforts to fully implement global laboratory containment activities. They also encouraged plans to transition the infrastructure of the GPEI for the long-term, to ensure the assets and infrastructure established to eradicate polio will continue to benefit broader public health efforts even after the disease is gone.  At the World Health Assembly in May, the GPEI will present a strategic roadmap towards polio transition and the development of a post-certification strategy.

With all technical and programmatic building blocks in place to achieve success, ministries urged all stakeholders to ensure that the necessary financial resources to fully implement the Endgame Plan are rapidly mobilized.

Closing the discussion, partners from civil society addressed the ministries through Rotary International with a clear call to action:  “We must protect hard won gains by sustaining immunity levels and careful monitoring of virus transmission.  An additional US$1.3 billion is needed through 2019 to reach more than 400 million children in up to 60 countries and to ensure high quality surveillance.  The eradication of polio will be a monumental achievement by a global partnership.  Such achievements exemplify what we can do when united for a common purpose.  Together we can end polio and forever build a better future for all children.”