A multi-centre study on epidemiology and clinical characteristics of human metapneumovirus infection in Sri Lanka from 2021 to 2024.

Introduction. Human metapneumovirus (hMPV), first identified in 2001, is one of the major respiratory pathogens causing acute respiratory tract infections (ARTIs). In Sri Lanka, data on epidemiology and clinical characteristics of hMPV infections are limited. In this study, we aimed to investigate the epidemiology and clinical characteristics of hMPV infection in adults and children with ARTIs in different locations in Sri Lanka from January 2021 to December 2023. Methods. A total of 1,582 respiratory samples from patients with ARTIs were enrolled from four tertiary care hospitals. Nasopharyngeal swab samples were subjected to real-time reverse transcriptase PCR to test for hMPV using a commercial multiplex assay. Demographic and clinical data were extracted from the patients' clinical records. A selected subset of positive samples was subjected to genomic sequencing using an amplicon-based approach with the Respiratory Pathogen ID/AMR Library Prep and Enrichment Kit using the Illumina platform. Results. hMPV infection was identified in 1.64% (26/1,582) of patients, with the majority being children under 5 years of age. The co-infection rate was 0.34% with other respiratory viruses. The most common clinical presentation in hMPV infection included acute upper respiratory tract infection with fever, cough and cold and sore throat. Conclusion. hMPV is an important respiratory pathogen in children, causing ARTIs. hMPV-infected patients showed a range of respiratory symptoms with varying severity ranging from common cold to life-threatening lower respiratory tract infections. Continuous surveillance on hMPV infection may help in monitoring the hMPV activity, which will help in tracking the emergence of hMPV infections.