Table 2. Utilization of Shigella flexneri 2a and S. sonnei controlled human infection models.
| Evaluation | Challenge agent | Product under evaluation | Naïve attack rate (n/N) | Treated attack rate (n/ N) | Efficacy (%) a | References |
|---|---|---|---|---|---|---|
| Homologous re-challenge | S. flexneri 2a | Strain 2457T | 22/39 | 3/15 | 64 | DuPont et al. (1972b) |
| S. flexneri 2a | Strain 2457T | 11/12 | 3/11 | 71 | Kotloff et al. (1995a) | |
| S. sonnei | Strain 53G (frozen) | 8/12 | 0/6 | 100 | Herrington et al. (1990) | |
| Antibiotic | S. flexneri 2a | Rifaximin | 6/15 | 0/15 | 100 | Taylor et al. (2006) |
| S. flexneri 2a | Rifaximin | 13/15 | n/a | n/a | Taylor et al. (2008) | |
| Passive Ig | S. flexneri 2a | Bovine IgG | 5/11 | 0/10 | 100 | Tacket et al. (1992) |
| Homologous vaccine candidate | S. flexneri 2a b | Heat-killed whole cell | 19/30 | 18/25 | -14 | Shaughnessy and Olsson (1946) |
| S. flexneri 2a b | Irradiated whole cell | 19/30 | 23/28 | -30 | Shaughnessy and Olsson (1946) | |
| S. flexneri 2a | EcSF2a-1(E. coli K-12—S. flexneri 2a OAg hybrid live-oral) | 6/24, 52/88 | 1/15, 30/68 | 73, 25 | DuPont et al. (1972b) | |
| S. flexneri 2a | Streptomycin-dependent whole cell | 6/24, 52/88 | 3/31, 16/53 | 61, 49 | DuPont et al. (1972b) | |
| S. flexneri 2a | EcSF2a-2 (E. coli K-12 aroD mutant—S. flexneri 2a OAg hybrid live-oral) | 12/14 | 10/16 | 27 | Kotloff et al. (1995b) | |
| S. flexneri 2a | SC602 (live attenuated S. flexneri 2a icsA mutant) | 6/7 | 0/7 | 100 | Coster et al. (1999) | |
| S. flexneri 2a | Proteosome-Sflex2a LPS | 13/13 | 9/14 | 36 | Durbin et al. (2001) | |
| S. flexneri 2a | Invaplex50 NAT (Macromolecular complex containing IpaB, IpaC and S. flexneri 2a LPS) | 8/12 | 7/10 | -5 | NCT 00485134 | |
| S. flexneri 2a | Flexyn2a, bioconjugate (S. flexneri 2a OAg conjugated to P. aeruginosa exotoxin A) | 18/29 | 13/30 | 30 | Talaat et al. (2021) | |
| S. sonnei (Frozen) | WRSs1 (Live attenuated S. sonnei virG mutant) | 1/6 c | 0/13 | n/a c | Pitisuttithum et al. (2016) | |
| S. sonnei (Lyophilized) | 1790GAHB (S. sonnei GMMA-technology) | 15/32 | 12/28 | − 9.4 | Frenck et al. (2021) |
a
Efficacy outcomes presented as the per protocol definition for shigellosis
b
S. flexneri 2a strain was FW rather than the more commonly used 2457T
c
Study performed in Thai adults yielded lower than anticipated naïve AR, and the authors reported “no efficacy against dysentery and diarrhea”