Authors: Kimberley Ndungu, Future Science Group
An independent commission of experts concluded that wild type poliovirus type 3 (WPV3) has been eradicated worldwide, representing a historic achievement.
“The achievement of polio eradication will be a milestone for global health. Commitment from partners and countries, coupled with innovation, means of the three wild polio serotypes, only type one remains,” commented Tedros Adhanom Ghebreyesus, Director-General of WHO and Chair of the Global Polio Eradication Initiative (GPEI) Polio Oversight Board “We remain fully committed to ensuring that all necessary resources are made available to eradicate all poliovirus strains. We urge all our other stakeholders and partners to also stay the course until final success is achieved.”
There are three immunologically distinct strains of the poliovirus:
- wild poliovirus type 1
- wild poliovirus type 2
All three strains cause the same symptoms, such as irreversible paralysis or even death, however, there are both genetic and virologic differences that make the strains three separate viruses, therefore, they require eradication separately.
Wild poliovirus type 2 was eradicated in 2015 and the last case of WPV3 was detected in Nigeria in 2012. The investment in skilled workers, innovative tools and a global network of laboratories have helped verify that no WPV3 exists anywhere in the world – apart from specimens locked in secure containment.
“This this is a significant achievement that should reinvigorate the eradication process and provides motivation for the final step – the eradication of wild poliovirus type 1. This virus remains in circulation in just two countries: Afghanistan and Pakistan. We cannot stop our efforts now: we must eradicate all remaining strains of all polioviruses. We do have good news from Africa: no wild poliovirus type 1 has been detected anywhere on the continent since 2016 in the face of ever improving surveillance. Although the region is affected by circulating vaccine-derived polioviruses, which must urgently be stopped, it does appear as if the continent is free of all wild polioviruses, a tremendous achievement,” explained David Salisbury, chair of the independent Global Commission for the Certification of Poliomyelitis Eradication.
With ongoing commitment to the international development community, the eradication of WPV3 suggests that a polio-free world is possible. Therefore, as part of Global Health Week, the Last Mile Forum (Abu Dhabi, United Arab Emirates, November 2019) will have a focus on the eradication of the world’s deadliest diseases and allow world leaders and civil societal organizations to contribute to the last mile of polio eradication.
Polio eradication efforts have saved the world more than US$ 27 billion in health costs since 1988. Further, a polio-free world is projected to save an additional US$ 14 billion by 2050, compared with the cost of controlling the virus.
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Where does polio still cause illness?
There are three countries that have never stopped the transmission of polio – Afghanistan, Nigeria and Pakistan. They face challenges such as insecurity, weak health systems and poor sanitation.
Which polio vaccine is currently being used?
There are two forms of vaccine available for polio, oral polio vaccine and inactivated polio vaccines. However, there is also ongoing research to formulate a polio vaccine that doesn’t require a ‘cold chain’, i.e., to be kept in a refrigerated environment; this would allow for improved vaccine coverage in remote or low-resource areas.
What are the criteria for polio eradication?
A country is regarded ad ‘polio free’ if no cases have been detected for a year. For a polio virus to be certified as eradicated worldwide, at least three years of good surveillance without cases needs to be achieved, although this period might be longer.
How many polio cases were there in 2018?
There were 33 diagnosed wild polio virus cases worldwide in 2018, representing a 99.99% decrease in cases from when the polio eradication effort began in 1988. All these cases were due to wild polio virus type 1.