Report of the 1966-67 cholera vaccine field trial in rural East Pakistan. 3. The lack of effect of prior vaccination or circulating vibriocidal antibody on the severity of clinical cholera.

In a controlled study, it has been shown that the prior administration of cholera vaccine had no beneficial effect on the clinical course of cholera as measured by either the condition of the patient on admission to hospital or the subsequent course of the disease. In fact, the disease was, if anything, more severe in those who had received cholera vaccine. Although the presence of a high vibriocidal titre is associated with protection from cholera, pre-existing antibody had no effect on the clinical course of the disease in those patients who developed cholera.