Safety, immunogenicity, and efficacy of live attenuated Vibrio cholerae O139 vaccine prototype

Lancet. 1995 Apr 15;345(8955):949-52. doi: 10.1016/s0140-6736(95)90698-3.


New vaccines are needed to prevent cholera caused by Vibrio cholerae O139. Attenuated V cholerae O139 vaccines were made by deleting multiple copies of the cholera-toxin genetic element from two virulent strains of the organism, MO10 and AI4456. The deletion mutants were further modified by insertion of a construct that encoded the B subunit of cholera toxin, thus generating strains Bengal-3 and VRI-16. A stable spontaneous non-motile derivative of Bengal-3 was isolated and designated Bengal-15; VRI-16 is naturally non-motile. Bengal-3, Bengal-15, and VRI-16 were evaluated as oral single-dose cholera vaccine candidates in 4 volunteers each, and MO10 was given to 3 volunteers. 1 of 4 volunteers who received Bengal-3 and all 3 who received MO10 had diarrhoea. VRI-16 caused no significant symptoms but was not immunogenic. Bengal-15 produced few symptoms and was nearly as immunogenic as MO10. Subsequently, Bengal-15 was given to 10 volunteers at a dose of 10(8) colony-forming units. No volunteers had diarrhoea, and other subjective symptoms were as common in vaccinees as in 3 buffer recipients. 1 month after vaccination, 7 vaccinees, the 3 buffer recipients, and 3 unimmunised subjects were challenged with 5 x 10(6) colony-forming units of V cholerae O139. 5 of 6 controls had cholera-like diarrhoea. By contrast, 1 of 7 vaccinees had diarrhoea, which was mild and had a long incubation period. Vaccine protective efficacy was 83%. Our results indicate the Bengal-15 is a safe live attenuated vaccine candidate for cholera caused by the O139 serogroup.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adolescent
  • Adult
  • Antibodies, Bacterial / blood
  • Cholera / prevention & control
  • Cholera Vaccines* / administration & dosage
  • Cholera Vaccines* / adverse effects
  • Cholera Vaccines* / immunology
  • Double-Blind Method
  • Humans
  • Vaccines, Attenuated
  • Vibrio cholerae / immunology


  • Antibodies, Bacterial
  • Cholera Vaccines
  • Vaccines, Attenuated