WHO Declares Vaccine-Derived Polio Outbreak in Papua New Guinea

The World Health Organization (WHO) has declared a polio outbreak in Papua New Guinea after detecting circulating vaccine-derived poliovirus type 2 (cVDPV2) in stool specimens from two healthy children in Lae city, Morobe province. This marks the first polio outbreak in the country since 2018, with vaccination coverage at only about 44% for the third dose needed for protection, prompting efforts to increase vaccinations and monitor further transmission. Vaccine-derived poliovirus outbreaks continue to pose a significant public health threat beyond the endemic wild polio regions of Pakistan and Afghanistan, affecting countries such as Nigeria and Ethiopia this year. Poliomyelitis primarily spreads through the fecal-oral route, can cause paralysis and death in young children, and often presents no symptoms, complicating detection. Meanwhile, Madagascar has successfully halted transmission of variant poliovirus type 1 following extensive vaccination campaigns and surveillance, achieving the criteria for outbreak closure after no new cases since September 2023. This contrast highlights ongoing challenges in polio eradication, emphasizing the need for robust immunization and monitoring programs globally.