COMPARISON OF ALTERNATIVE BUFFERS FOR USE WITH A NEW LIVE ORAL CHOLERA VACCINE, PERU-15, IN OUTPATIENT VOLUNTEERS

During development of Peru-15, a new live oral vaccine for cholera, th e role of buffer needed to be evaluated, Generally, oral bacterial vac cines are acid labile and need to be administered by using a formulati on which protects them from gastric acid, We compared three different buffers for use with Peru-15, including a standard bicarbonate-ascorbi c acid buffer, Alka-Seltzer, and a new electrolyte-rice buffer, CeraVa cx. Saline served as the control, Thirty-nine healthy adult volunteers received Peru-15 (10(8) CFU) with one of the three buffers or saline in a double-masked study, The volunteers were monitored for symptoms f or 7 days after the dose, serum was tested for antibody responses by v ibriocidal antibody and immunoglobulin G antitoxin enzyme-linked immun osorbent assays, and stool samples were tested for excretion of the va ccine strain, Side effects were minimal in all groups, All 30 voluntee rs who took Peru-15 with a buffer showed significant rises in vibrioci dal antibody titer, The magnitude of the rises was higher in the CeraV acx group than in the other two buffer groups, Four of nine volunteers who took the vaccine with saline also showed increased titers, but th ey were lower than those in any of the three buffer groups, Excretion of the vaccine strain was similar in the buffer groups, but excretion was not associated with the magnitude of the vibriocidal responses, Ex cretion of Peru-15 was not detected in the saline group. We conclude t hat buffer does amplify the serological response to Peru-15 and that C eraVacx may provide benefits not provided by other buffers.