Health status of Thai volunteers in a cholera vaccine trial

One hundred and seventy-one male adults were screened in recruitment of volunteers for a cholera vaccine trial. A full medical history and a physical examination were performed on each subject. The percentages of subjects vaccinated against cholera and typhoid within twelve months were 4 and 1 per cent respectively, while 88 and 15 per cent respectively had been vaccinated more than a year. Biochemical screening revealed abnormal liver function tests in 40.7 per cent, specifically alkaline phosphatase (8%), glutamic oxaloacetic transaminase (8%), glutamic pyruvic transaminase (4.7%), total bilirubin (10%) and globulin (34%). Ten (6%) of the volunteers were positive for hepatitis B surface antigen (HBs-Ag). The total white cell count was elevated in 13.5 and 81.9 per cent had eosinophilia. Stool examination revealed infection with Hookworm (54.9%), Opisthorchis viverrini (29.8%), Strongyloides stercoralis (5.3%), Endolimax nana (3.5%), Giardia lamblia (5.3%) and Taenia saginata (2.9%). Few volunteers (13.4%) had abnormal microscopic examination of urine sediment. Only 57 subjects were considered suitable to be volunteers. Each of these subjects had no significant past medical, surgical or psychological illness. None had been vaccinated against cholera within the previous 12 months and no subject had abnormalities on physical examination or routine biochemical and haematological screening. The large number of subjects excluded from recruitment (67%) emphasized the importance of proper screening of volunteers for any vaccine trial.