Mucosal immunization with Shigella flexneri outer membrane vesicles induced protection in mice

► Shigella flexneri outer membrane vesicles (OMV) were entrapped in polyanhydride nanoparticles. ► OMV and NP-OMV were immunogenic in mice after a single administration by either intradermal or mucosal routes. ► OMV and OMV-NP were safe and protective in mice. ► NP-OMVs by intradermal route elicited full protection. ► Both OMVs and OMV-NP induced full protection by the nasal or conjuntival routes.