Vaginal thrush, also known as vaginal yeast infection, is an inflammation caused by a type of yeast called Candida albicans. Vaginal thrush is very common and about three in four women will have at least one episode of thrush at some point during their life.aginal thrush, also known as vaginal yeast infection, is an inflammation caused by a type of yeast called Candida albicans. Vaginal thrush is very common and about three in four women will have at least one episode of thrush at some point during their life.