Emergence of GII.4 Sydney [P16]-like Norovirus-Associated Gastroenteritis, China, 2020–2022

Abstract

Newly evolved GII.4 Sydney[P16] norovirus with multiple residue mutations, already circulating in parts of China, became predominant and caused an abrupt increase in diagnosed norovirus cases among children with gastroenteritis in Shanghai during 2021–2022. Findings highlight the need for continuous long-term monitoring for SHGII.4-2020 and emergent GII.4 norovirus variants.