Human respiratory syncytial virus (HRSV) and human metapneumovirus (HMPV) cause disease in premature newborns, hospitalized children and immune-compromised patients, and are also involved in asthma exacerbations. Corti et al. identified a human monoclonal antibody (named MPE8) that neutralized HRSV and HMPV as well as bovine RSV and pneumonia virus of mice (PVM). MPE8 reduced viral titres in mouse models of HRSV and HMPV infection, and had therapeutic efficacy against lethal PVM infection. The antibody was found to selectively recognize epitopes on the pre-fusion viral F protein. These results suggest that MPE8 could be used against HRSV and HMPV infections and that the pre-fusion F protein could be a target for vaccine development.