Epidemiology of Human Metapneumovirus Infection-A Systematic Review and Meta-Analysis.

BACKGROUND: Human metapneumovirus (hMPV) is a globally circulating respiratory pathogen. The objective of this systematic review is to evaluate the prevalence, case fatality rate, age-related severity, and seasonality of hMPV in the group of Acute Respiratory Infections (ARIs) and Community-Acquired Pneumonia (CAP). METHODS: We conducted a systematic review and meta-analysis of articles on hMPV published from January 2001 to June 2025. Following PRISMA 2020 guidelines, we systematically searched PubMed and ScienceDirect for eligible articles using strict inclusion and exclusion criteria. Random-effects meta-analysis was performed to estimate pooled prevalence, and subgroup analyses were conducted by study group, geographic region, COVID-19 period, and age group. RESULTS: One hundred one studies met the inclusion criteria, of which 96 contributed to the meta-analysis. The pooled global prevalence of hMPV was 6% (95% CI: 5%-7%). Prevalence estimates were highest in patients with respiratory tract infections (RTIs) patients (6%) and in South America (10%). Age-stratified analysis showed a high prevalence in children under 5 years (7%). Seroprevalence studies demonstrated low hMPV antibody prevalence in young children less than 1 year. The case fatality rate ranged from 2.5% in elderly populations to 4.4% in severe pediatric cases. hMPV mainly affects children under 2 years, with a smaller burden in older adults. Seasonal peaks were typically observed in late winter to early spring. CONCLUSION: hMPV remains an important cause of respiratory disease worldwide, with a disproportionate burden on children. The significant heterogeneity across studies and evidence of publication bias highlight the need for standardized surveillance.