Polio Remains an Emergency of International Concern

During the 30th meeting of the World Health Organization (WHO) polio emergency committee, it was agreed that the international polio situation remains a public health emergency of international concern (PHEIC).

This agreement is based on the cross-border spread of circulating vaccine-derived polioviruses (cVDPV) and the unpredictable situation of wild poliovirus 1 (WPV1) transmission in Afghanistan.

Currently, cVDPV cases have been detected in 30 countries in Africa, Europe, and the Eastern Mediterranean region.

And recently, Guinea Bissau, Mauritania, and Ukraine reported new circulating vaccine-derived poliovirus type 2 (cVDPV2) cases in 2021.

The number of confirmed cVDPV2 cases in 2021 has reached 420, of which 266 have occurred in the African country of Nigeria.

The Committee was concerned the outbreak in Nigeria had recently spilled into Niger and Cameroon. 

Based on analysis of genetic linkages between viruses, the cross-border spread remains common, with ten documented importations into ten countries in the second quarter of 2021.

'The Committee recognizes the concerns regarding the lengthy duration of the polio PHEIC but concluded that there are still significant risks despite apparent progress made in the two endemic countries and that the coming three months would be a critical period to monitor the situation there closely,' said the WHO on November 22, 2021.

And, the WHO committee noted that it had endorsed the transition of nOPV2 from initial to broader use, based on the findings of independent safety and genetic stability assessment.

The Committee also underlined the importance of timely, quality outbreak response with the immediately available type-2 vaccine (nOPV2).

The Director-General endorsed the Committee's recommendations for countries meeting the definition for 'States infected with WPV1, cVDPV1 or cVDPV3 with potential risk for international spread', 'States infected with cVDPV2 with potential risk for international spread' and for 'States no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV' and extended the Temporary Recommendations under the IHR to reduce the risk of the international spread of poliovirus, effective November 5, 2021.

Polio, or poliomyelitis, is a crippling and potentially deadly disease, says the U.S. CDC.

It is caused by the poliovirus. The virus spreads from person to person and can invade an infected person's brain and spinal cord, causing paralysis.

However, polio can be prevented with vaccines.

The inactivated polio vaccine is the only polio vaccine that has been given in the United States since 2000.

But bivalent OPV is used in most middle- and low-income countries and for global polio eradication activities.

On November 1, 2021, the CDC reissued its Level 2 Travel Advisory regarding polio outbreaks in various countries. And another advisory for Asia and Eastern Europe.