TY - JOUR KW - bacillary dysentery KW - infectivity KW - vaccines KW - volunteers AU - Karen Kotloff AU - James Nataro AU - Genevieve Losonsky AU - Steven Wasserman AU - Thomas Hale AU - David Taylor AU - Jerald Sadoff AU - Myron Levine AB - {In the absence of a definitive immunologic correlate of protection against shigellosis, promising Shigella vaccine candidates have been selected based on their ability to confer resistance against experimental challenge with wild-type Shigella in healthy adult volunteers. A limitation of this model has been the low and often variable attack rate of illness among controls, necessitating repeated inpatient studies to demonstrate statistically significant results. In this study, the Shigella challenge model was modified by using bicarbonate buffer instead of skimmed milk as the delivery vehicle to enhance survival of the ingested challenge inoculum. To determine the ability of the modified model to detect protective efficacy, 11 veteran volunteers (previously challenged with S. flexneri 2a in bicarbonate buffer) and 12 immunologically naive control subjects were challenged with 1.4 × 103 c.f.u. S. flexneri 2a. Shigellosis occurred in 3 veterans and 11 control subjects (27 vs 92% BT - Vaccine DA - jan DO - 10.1016/0264-410X(95)00102-7 LA - eng M1 - 16 N2 - {In the absence of a definitive immunologic correlate of protection against shigellosis, promising Shigella vaccine candidates have been selected based on their ability to confer resistance against experimental challenge with wild-type Shigella in healthy adult volunteers. A limitation of this model has been the low and often variable attack rate of illness among controls, necessitating repeated inpatient studies to demonstrate statistically significant results. In this study, the Shigella challenge model was modified by using bicarbonate buffer instead of skimmed milk as the delivery vehicle to enhance survival of the ingested challenge inoculum. To determine the ability of the modified model to detect protective efficacy, 11 veteran volunteers (previously challenged with S. flexneri 2a in bicarbonate buffer) and 12 immunologically naive control subjects were challenged with 1.4 × 103 c.f.u. S. flexneri 2a. Shigellosis occurred in 3 veterans and 11 control subjects (27 vs 92% PY - 1995 EP - 1488–1494 T2 - Vaccine TI - A modified {Shigella} volunteer challenge model in which the inoculum is administered with bicarbonate buffer: clinical experience and implications for {Shigella} infectivity UR - https://www.sciencedirect.com/science/article/pii/0264410X95001027 VL - 13 SN - 0264-410X ER -