Typhoid Vaccines Ready for Implementation

Abstract

Enteric fevers encompass typhoid fever caused by Salmonella enterica serotype Typhi (S. Typhi) and paratyphoid fever caused by serotype Paratyphi A or B (S. Paratyphi). These human-restricted pathogens are acquired by ingesting contaminated water or food, and in the individual patient, one cannot differentiate clinically which agent is causing illness. S. Typhi expresses a capsular “Vi” (for virulence) polysaccharide, whereas S. Paratyphi A and B cannot synthesize Vi.