Effective protection against secondary pneumococcal pneumonia by oral vaccination with attenuated Salmonella delivering PspA antigen in mice

► Secondary pneumococcal infection exacerbates influenza-induced pneumonia. ► Oral vaccination with RASV protect mice against secondary pneumococcal pneumonia. ► Oral RASV induce long-term protection. ► Antiviral treatment synergistically enhances protective efficacy of oral RASV.