Epidemiology and genetic variation of acute viral gastroenteritis in children under five years in the Middle East (2020–2025): a systematic review and meta-analysis

BACKGROUND: Acute viral gastroenteritis remains a major cause of morbidity and hospitalization among children under five years worldwide. In the Middle East, epidemiological and molecular evidence remains fragmented, particularly in the post-COVID-19 period. This systematic review and meta-analysis aimed to synthesize recent data (2020-2025) on the prevalence, genetic diversity, and co-infection patterns of enteric viruses among children aged 0-59 months in the region. METHODS: A comprehensive search of PubMed/MEDLINE, Scopus, Web of Science, ScienceDirect, and the WHO Global Index Medicus identified eligible observational and molecular studies published between 1 January 2020 and 31 May 2025. Study selection, data extraction, and risk-of-bias assessment were independently conducted by two reviewers according to PRISMA 2020 guidelines. The protocol was prospectively registered in PROSPERO (CRD420251064184). Pooled prevalence estimates were calculated using a random-effects model with Freeman-Tukey double arcsine transformation. RESULTS: Forty-three studies, including 22,021 children tested for acute gastroenteritis (AGE) from nine Middle Eastern countries, met the inclusion criteria. Rotavirus (28 studies) was the most prevalent pathogen, with a pooled prevalence of 30.4% (95% CI: 24.3-35.8; I² = 96%, p < 0.001), followed by norovirus (12 studies) at 23.5% (95% CI: 11.4-29), adenovirus (13 studies) at 11.3% (95% CI: 8.6-17.6), and astrovirus (10 studies) at 6.0% (95% CI: 1.3-12.7). Predominant rotavirus genotypes included G1, G2, G3, and G9, commonly combined with P[8], P[4], and P[6], with G3P[8] and G1P[8] as dominant constellations. Norovirus GII.4 and recombinant GII.4[P16] strains were frequently detected. Viral co-infections were also reported, particularly involving rotavirus and other enteric viruses. CONCLUSION: Rotavirus and norovirus remain the principal viral causes of pediatric acute gastroenteritis in the Middle East and exhibit substantial genetic diversity with frequent co-infection patterns. However, marked inter-study heterogeneity and uneven geographic representation limit regional generalizability. Strengthened molecular surveillance, standardized diagnostic approaches, and continuous genotype monitoring are essential to optimize prevention strategies and vaccination policies across the region.