There is an urgent need for effective and affordable cholera vaccines both for use in cholera outbreaks and in mass vaccination campaigns. The main goal of the project has been to develop a simplified killed oral cholera vaccine based on a single Vibrio cholerae O1 vaccine strain and a single inactivation method, which could replace three virulent O1 strains inactivated by two different methods used in current licensed vaccines thereby reducing production costs. The vaccine should ideally also contain recombinantly produced low-cost cholera toxin B subunit (rCTB) and be in a formulation that would avoid both the need for a cold chain and for co-administration of a bicarbonate buffer.