Duration of Infection-Derived Immunity to Cholera

Abstract

Four volunteers were rechallenged with Vibrio cholerae (10⁶ classical Ogawa 395 organisms) 33–36 months after their initial induced cholera infection; none of the four veterans and four of five control volunteers developed diarrhea (P = 0.04). All control subjects, but only one veteran, had positive coprocultures. Three of the four veterans had significant levels of serum IgO antitoxin before challenge, but none had measurable intestinal levels of secretory 19A antitoxin. Significant rises in levels of serum vibriocidal and antitoxic antibody occurred in all control subjects and in two veterans, who also manifested rises in levels of intestinal secretory 19A antitoxin. The impressive duration of infection-derived immunity suggests that the most promising approach to development of cholera vaccines may be to mimic natural immunity with orally administered, attenuated strains of V. cholerae.