The evolving landscape of Norovirus GII genotypes in Asia: A systematic review and meta-analysis.

Background: Norovirus is a leading cause of acute gastroenteritis globally, with genotypic variation influencing epidemiology and disease outcomes. Understanding the distribution and prevalence of different Norovirus genotypes is crucial for public health surveillance and intervention strategies.

Methods: We conducted a systematic review of Norovirus genotypes in Asia from 2000 to 2023. The review adhered to PRISMA Guidelines and was registered with PROSPERO (ID CRD42024572647). We extracted data on the prevalence of 22 genotypes and their genetic variations over time.

Results: The review highlighted Norovirus GII.4 as highly prevalent across Asia, particularly in India, Taiwan, Vietnam, and China. GII.2 dominated Indonesia, GII.3 prevailed in Malaysia, Russia, and Bangladesh, GII.7 in Bangladesh, and GII.17 in China, Taiwan, and Nepal, with notable epidemiological shifts between 2012 and 2016 and GII.4 resurgence from 2017.

Conclusion: The study highlights the dynamic nature of Norovirus genotypic distribution in Asia, with both persistent dominance of certain genotypes and notable regional variations. The cyclic patterns of genotype prevalence, particularly the shifts between GII.4 and GII.17, underline the need for ongoing genotypic surveillance to inform targeted public health responses. The data underscores the complexity of Norovirus epidemiology and the importance of maintaining vigilance in monitoring emerging and re-emerging strains.