A human volunteer challenge model using frozen bacteria of the new epidemic serotype, V. cholerae O139 in Thai volunteers

Academic Article


  • A total of 35 volunteers were recruited for an IRB-approved inpatient dose-escalation challenge. The goal was to identify a dose that produced an observed cholera attack rate ≥80% and an illness of sufficient severity during the defined study period such that the model would be useful for determining vaccine protection. Volunteers were challenged in groups of 5 with V. cholerae O139 that had been reconstituted immediately before use. Only 2 out of 5 volunteers who received the lowest dose (4.3 × 104cfu) had diarrhea. As the inoculum size increased, the attack rate of diarrhea increased to 3-4 of 5 volunteers. At the highest dose tested, approximately 5 × 107cfu, the attack rate was 73%. We recommend the use of frozen V. Cholera O139 in a human experimental challenge model to assess cholera vaccine efficacy (VE) in a cholera endemic area but with 4 days observation period before initiation of tetracycline to allow assessment of severity. © 2001 Elsevier Science Ltd. All rights reserved.
  • Published In

  • Vaccine  Journal
  • Digital Object Identifier (doi)

    Author List

  • Pitisuttithum P; Cohen MB; Phonrat B; Suthisarnsuntorn U; Bussaratid V; Desakorn V; Phumratanaprapin W; Singhasivanon P; Looareesuwan S; Schiff GM
  • Start Page

  • 920
  • End Page

  • 925
  • Volume

  • 20
  • Issue

  • 5-6