The Challenge of Developing Global Health Vaccines Against the Invasive Salmonelloses: Enteric Fever and Invasive Nontyphoidal Salmonella Disease
Calman A. MacLennan
from: Advanced Vaccine Research Methods for the Decade of Vaccines (Edited by: Fabio Bagnoli and Rino Rappuoli). Caister Academic Press, U.K. (2015) Pages: 387-410.
There is a growing awareness of the significance of Salmonella disease as a major public health concern, particularly in the developing world. This encompasses both enteric fever, caused by Salmonella enterica serovars Typhi (S. Typhi) and Paratyphi A (S. Paratyphi A), and gastrointestinal and invasive disease caused by Salmonella serovars collectively known as nontyphoidal Salmonellae (NTS). While responsible for gastroenteritis in high-income countries, NTS are a common cause of fatal invasive disease in low-income countries, particularly in Africa. Currently available licensed vaccines for use in man are Vi capsular polysaccharide (Vi CPS) and the Ty21a live attenuated vaccine. Both vaccines are targeted against S. Typhi and offer limited or no cross-protection against other serovars of Salmonella. Even against S. Typhi, these vaccines have some significant draw-backs, the main one being their lack of efficacy in children under two years of age. There is increased recognition that new vaccines are required to deal effectively with the global problem of Salmonella. A proper understanding of the modalities of protective immunity against Salmonella is required for the rational development of such vaccines, along with an appreciation of the targets of protective acquired immunity. At an epidemiological level, it is critical to know which population groups most need vaccination against salmonellosis. This chapter deals with the challenges posed by Salmonella to vaccine development. It considers the optimal requirements for new vaccines, particularly those with broad specificity that can be used across a spectrum of ages. The chapter also reviews vaccines against Salmonella that are currently in development and discusses innovations and prospects for vaccines of the future read more ...