Clinical features and genomic characteristics of post-pandemic human metapneumovirus infections in hospitalized Taiwanese children.

OBJECTS: Human metapneumovirus (HMPV) is a well-recognized respiratory viral pathogen and contributes to significant disease burden among children and high-risk populations. This study describes the epidemiology, clinical features and circulating genotypes of a post-pandemic HMPV outbreak in Taiwan, 2023.

METHODS

Hospitalized children with HMPV infection confirmed by molecular diagnostics at two hospitals between January and June 2023 were enrolled in this study. Some nasal swabs were obtained from enrolled patients and sent for HMPV genotype sequencing. Medical information was retrieved and analyzed retrospectively.

RESULTS

The HMPV cases were first identified in February and peaked in May and June. A total of 69 HMPV cases were identified in this study (22.5 %, 69/306). The median age of infected cases was 43 months, and 34 were male (49.3 %). Half of the cases (38, 55.1 %) were diagnosed with bronchopneumonia or pneumonia. Forty patients received bronchodilator therapy (60 %), and 36 were treated with antibiotics (52.2 %). Phylogenetic analysis indicated lineages A2.2.2 and B2 were predominant genotypes for this outbreak. In addition, 73.3 % of HMPV-A strains were confirmed as the A2.2.2 with a 111 nt duplication variant.

CONCLUSION

HMPV lineage A2.2.2 111nt-dup and B2 were responsible for the 2023 HMPV outbreak in Taiwan. A long-term nationwide HMPV surveillance system is mandatory in Taiwan.