Disclosed is the use of a type II transmembrane serine protease (TTSP) inhibitor in the preparation of a pharmaceutical composition for preventing or reducing the accumulation of influenza-infected alveolar macrophages, influenza-infected neutrophils and/or influenza-infected epithelial cells in the lungs of a subject that has been exposed to or challenged with influenza virus in a subject wherein the TMPRSS2 inhibitor is an antibody or antigen-bending fragment thereof which specifically binds TMPRSS2 and inhibits the protease activity of TMPRSS2 but does not substantially inhibit the protease activity of any other TTSP.
