Figure 2. Established and new Salmonella vaccines, and how they relate to each other. (Adapted with permission from: MacLennan CA, Chapter 17 The challenge of developing global health vaccines against the invasive salmonelloses: enteric fever and invasive nontyphoidal Salmonella disease. Advanced Vaccine Research Methods for the Decade of Vaccines, Editors Bagnoli F, Rappuoli R, Publisher Caister Academic Press.)