TABLE 12.

Shigella vaccine candidates^a

Vaccine type	Candidate	Current stage	Developer(s)
Attenuated	CVD 1208S based on S. flexneri 2a	Phase 1	CVD
	WRSS1 based on S. sonnei	Phase 2b	WRAIR
	ShigETEC LPS-free cell	Phase 1	EveliQure
Vectored	Ty21a typhoid vaccine expressing O antigens of S. sonnei or a combination of S. sonnei, S. flexneri 2a and 3a, and S. dysenteriae O antigen	Preclinical	Protein Potential
Inactivated	Sf2aWC, a formalin-killed S. flexneri 2a whole-cell vaccine	Phase 1	WRAIR and PATH
	Shigella truncated mutant (350)	Preclinical	IVI and PATH
Conjugate	Chemical glycoconjugates of S. sonnei and S. flexneri 2a	Phase 3	NIH Institute for Child Health and Human Development
	Recombinant bioconjugate	Phase 2b	LimmaTech Biologics and GSK
	Synthetic glycoconjugate	Phase 2	Institut Pasteur
Serotype-dependent mixture	InvaplexAR-DETOX, a chemically defined product consisting of invasion plasmid antigens and O antigens	Phase 1	WRAIR
	GMMA consisting of Shigella outer membrane vesicles from an overproducing strain	Phase 2	GSK
	Outer membrane vesicles: naturally secreted outer membrane vesicles of Shigella	Preclinical	University of Navarra, Spain
Serotype-independent proteins	IpaD/IpaB (DB) fusion	Preclinical	PATH
	PSSP-1 (Pan-Shigella surface protein 1)	Preclinical	IVI
	34-kDa OMP, an outer membrane protein conserved across multiple Shigella species	Preclinical	National Institute of Cholera and Enteric Diseases, India

^aCVD, Center for Vaccine Development, University of Maryland; ETEC, enterotoxigenic Escherichia coli; GMMA, Generalized Modules for Membrane Antigens; GSK, GlaxoSmithKline; IVI, International Vaccine Institute, South Korea; LPS, lipopolysaccharide; NIH, U.S. National Institutes of Health; WRAIR, Walter Reed Army Institute of Research. Adapted from references 334 and 337.