Notes from the Field : Circulating Vaccine-Derived Poliovirus Type 2 Emergences Linked to Novel Oral Poliovirus Vaccine Type 2 Use — Six African Countries, 2021–2023

Investigation and Outcomes Polio surveillance and laboratory data collected through the Global Polio Eradication Initiative were reviewed. During August 2021–July 2023, seven cVDPV2 emergences of nOPV2 origin from 61 paralytic cases and 39 environmental surveillance (sewage) samples were detected in six countries, all in Africa: Burundi, Central African Republic (CAR), Democratic Republic of the Congo (DRC), Nigeria, Tanzania, and Zambia (Figure). A. Deka, PhD3; Anfumbom Kfutwah, PhD4; Javier Martin, PhD5; Maël Bessaud, PhD6; Lester M. Shulman, PhD7; Kaija Hawes, MBA8; Ousmane M. Diop, PhD9; Ananda S. Bandyopadhyay, MBBS8; Simona Zipursky, MSc9; Cara C. Burns, PhD2 1Global Immunization Division, Global Health Center, CDC; 2Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC; 3Geospatial Research, Analysis, and Services Program, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia; 4Regional Polio Laboratory Network, World Health Organization Regional Office for Africa, Brazzaville, Republic of the Congo; 5Division of Vaccines, Medicines and Healthcare products Regulatory Agency, Potters Bar, United Kingdom; 6Institut Pasteur, Université Paris Cité, Virus Sensing and Signaling Unit, Paris, France; 7Central Virology Laboratory, Public Health Services, Israel Ministry of Health, Tel Aviv, Israel; 8Bill & Melinda Gates Foundation, Polio Team, Seattle, Washington; 9World Health Organization, Geneva, Switzerland.