Human metapneumovirus prevention within reach: advances in vaccines and monoclonal antibodies

Human metapneumovirus (HMPV) is a major respiratory pathogen that commonly causes mild to moderate upper respiratory tract infections in infants, with only a subset progressing to severe lower respiratory disease globally, particularly in older adults (aged ≥60 years) and individuals with compromised immunity. Efforts to develop an HMPV vaccine or immunoprophylaxis are still ongoing. The rapid advancements in understanding the virus's structure, particularly the surface proteins involved in immune evasion and viral fusion, have paved the way for promising vaccine-based and antibody-based interventions. The range now encompasses multiple vaccine candidates and monoclonal antibodies undergoing clinical trials; in particular, vaccines using different platforms such as virus-like particle-based, live attenuated, epitope-based, mRNA-based, vector-based, and plant-based approaches, in addition to monoclonal antibodies aimed at preventing or reducing disease severity. This Review emphasises innovative strategies for HMPV vaccine design and offers a detailed overview of HMPV vaccine candidates that are currently in clinical development, aimed at preventing a prevalent and severe infectious disease affecting young children (aged <5 years) and older adults globally.