Many viruses and bacteria infect humans through mucosal surfaces, such as those in the respiratory, gastrointestinal, and reproductive tracts. To help fight these pathogens, scientists are working on vaccines that can establish a front line of defense at mucosal surfaces. Only a few mucosal vaccines are in use and development of new mucosal vaccines could help protect against influenza, other respiratory viruses, HIV, herpes simplex virus, human papilloma virus, and possibly even cancer vaccines.
