Punnee PitisuttithumMitchell B. CohenBenjaluck PhonratUsanee SuthisarnsuntornValai BussaratidVarunee DesakornWeerapong PhumratanaprapinPratap SinghasivanonSornchai LooareesuwanGilbert M. SchiffBernard IvanoffDennis LangMahidol UniversityUniversity of CincinnatiOrganisation Mondiale de la SanteNational Institute of Allergy and Infectious Diseases2018-09-072018-09-072001-12-12Vaccine. Vol.20, No.5-6 (2001), 920-9250264410X2-s2.0-0035852276https://repository.li.mahidol.ac.th/handle/123456789/26426A 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.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyImmunology and MicrobiologyMedicineVeterinaryArticleSCOPUS10.1016/S0264-410X(01)00381-4