Two out of three wild poliovirus strains eradicated

29 October 2019

Article: 53/4304

On 24 October 2019, World Polio Day, the independent Global Commission for the Certification of Poliomyelitis Eradication announced that wild poliovirus type 3 (WPV3) has been eradicated worldwide. Following the eradication of smallpox and wild poliovirus type 2, this news represents a significant historic achievement.

There are three individual and immunologically-distinct wild poliovirus strains, these being wild poliovirus type 1 (WPV1), wild poliovirus type 2 (WPV2) and wild poliovirus type 3 (WPV3). Symptomatically, all three strains are identical, in that they cause irreversible paralysis or even death. But there are genetic and virologic differences which make these three strains separate viruses which must each be eradicated individually.

WPV3 is the second strain of the poliovirus to be wiped out, following the certification of the eradication of WPV2 in 2015. The last case of WPV3 was detected in northern Nigeria in 2012. Investments in skilled workers, innovative tools and a global network of laboratories have helped determine that no WPV3 exists anywhere in the world, apart from specimens locked in secure containment.

At a celebration event at the headquarters of the World Health Organization (WHO) in Geneva, Professor David Salisbury, chair of the independent Global Commission for the Certification of Poliomyelitis Eradication, presented the official certificate of WPV3 eradication to Dr Tedros Adhanom Ghebreyesus, WHO Director-General and Chair of the Global Polio Eradication Initiative (GPEI) Polio Oversight Board. Professor Salisbury welcomed this significant achievement, suggesting that it should reinvigorate the eradication process and provide motivation for the eradication of WPV1 which remains in circulation.

Source: WHO, 24 October 2019