Global trends in norovirus genotype distribution among children with acute gastroenteritis captured by NoroSurv, 2020-2025

Jennifer Cannon, CDC Foundation

Jennifer L. Cannon- CDC Foundation, Atlanta, Georgia, USA; Leslie Barclay- Centers for Disease Control and Prevention, Atlanta, Georgia, USA; Eddie Bartlett- Cherokee Nation Operational Solutions, Tulsa, Oklahoma, USA; Boris Relja1, CDC Foundation, Atlanta, Georgia, USA; Cindi Dayana Alvarez- Laboratorio Nacional de Salud, Guatemala City, Guatemala; Joseph Bonifacio- Research Institute for Tropical Medicine, Manila, Philippines; Filemon Bucardo- National Autonomous University of Nicaragua, León, Nicaragua; Javier Buesa- University of Valencia, Valencia, Spain; Estela Cordero-Laurent- Costa Rican Institute of Research and Education in Nutrition and Health (INCIENSA), Cartago, Costa Rica; Tulio M Fumian- Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil; Mark D Gonzalez- Children’s Healthcare of Atlanta, Atlanta, GA, USA; Luiza Miyanda Hatyoka- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; Mohammad Enayet Hossain- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; Claudio Lanata- Instituto de Investigacion Nutricional, Lima, Peru; Margarita K Lay- University of Antofagasta, Antofagasta, Chile; Jih-Hui Lin- Taiwan Centers for Disease Control, Taipei, Taiwan; Janet Mans- University of Pretoria, Pretoria, South Africa; Francisco Javier Duarte Martinez- Costa Rican Institute of Research and Education in Nutrition and Health (INCIENSA), Cartago, Costa Rica; Linda Mendoza- Laboratorio Nacional de Salud, Guatemala City, Guatemala; Mariel López Moya- Costa Rican Institute of Research and Education in Nutrition and Health (INCIENSA), Cartago, Costa Rica; Kanti Pabbaraju- Alberta Precision Laboratory, Edmonton, Alberta, Canada; Chao-Yang Pan- California Department of Public Health, Richmond, California, USA; Xiaoli Pang- University of Alberta, Calgary, Edmonton, Alberta, Canada; Corinna Pietsch- Leipzig University Hospital, Leipzig, Germany; Mustafizur Rahman- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; Naomi Sakon- Osaka Institute of Public Health, Osaka, Japan; Fabian Gómez Santiago- Instituto de Diagnóstico y Referencia Epidemiológicos, Mexico City, Mexico; Rangaraj Selvarangan- Children’s Mercy Hospitals and Clinics, Kansas City, Missouri, USA; Michelo Simuyandi- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; Tintu Varghese- Christian Medical College, Vellore, India; Sompong Vongpunsawad- Center of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, Thailand; Peter White- University of New South Wales, Sydney, Australia; Jan Vinjé- Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Molecular Epidemiology & Evolution

Young children are at increased risk for severe norovirus gastroenteritis and are infected by a broader diversity of norovirus strains than adults. NoroSurv is an established global network for norovirus strain surveillance among medically-treated children < 5 years of age. As of May 1, 2025, NoroSurv laboratories in 19 countries across 6 continents uploaded 3,555 norovirus sequences derived from stool specimens collected from September 1, 2020 to March 31, 2025. During this period, 26 genotypes and 52 strains were identified. GII.4 Sydney accounted for 46% (1,642/3,555) of the sequences, followed by GII.3 (12%; n = 443), GII.17 (9%; n = 313), GII.2 (7%; n = 248) and GII.6 (6%; n = 227). We detected new GII.4 variants, which peaked between January and March 2023 when 9% (41/478) of the sequences were GII.4 San Francisco and 8% (38/478) were GII.4 Wichita. GII.4 Allegany was primarily detected in Zambia in 2021. During peak years, the detection rates of the new GII.4 variants exceeded those of GII.4 Sydney in Costa Rica, Guatemala, Peru, and Zambia. Since September 2024, the overall GII.17 detection rate (48%; 61/128) surpassed that of GII.4 Sydney (26%; 33/128) and in Costa Rica, Guatemala, Philippines, Spain, and Thailand, over 60% of sequences submitted were GII.17. We are continuing to monitor the shifting distribution of norovirus genotypes through NoroSurv surveillance. Our data may inform norovirus vaccine development and adaptation and provide a baseline of global norovirus strain distribution for evaluating future vaccines in children.