The Global Polio Laboratory Network (GPLN) has confirmed the presence of a type 1 wild poliovirus (WPV1) in a child suffering from paralysis in Lilongwe, the capital of Malawi. Analysis shows that the virus is genetically linked to WPV1 that was detected in Pakistan’s Sindh province in October 2019.
The three-year-old girl in Malawi experienced onset of paralysis on 19 November 2021, and stool specimens were collected for testing. Sequencing of the virus conducted by the National Institute for Communicable Diseases in South Africa and the U.S. Centers for Disease Control and Prevention confirmed this case as WPV1.
There are 3 strains of wild poliovirus (WPV1, WPV2 and WP3V), WPV2 was declared eradicated in 2015 and no case of WPV3 has been found since the last reported case in Nigeria in November 2012. Only WPV1 remains and Pakistan and Afghanistan are the last 2 countries that are endemic for WPV1. One case of polio occurs following ~200 (WPV type 1) to ~1000 (type 2 or 3) WPV infections. Thus, one single polio case already is an outbreak – it is the tiny “tip of the iceberg” of widespread infections in the population (see VacciTUTOR Chapter 35).
Therefore, detection of WPV1 outside the world’s two remaining endemic countries is a serious concern and underscores the importance of prioritizing polio immunization activities. Until polio is fully eradicated, all countries remain at risk of importation and must maintain high vaccination coverage to protect all children from polio.
The Global Polio Eradication Initiative (GPEI) is supporting health authorities in Malawi to conduct a thorough assessment of the situation and begin urgent immunization activities in the sub region to mitigate any risk of spread.
Polio anywhere is a threat to children everywhere.
Source: Global Polio Eradication Initiative: GPEI
By Dr. Simone Müschenborn-Koglin Contributing Editor, GHP