Skin Patch Helps Prevent Traveler's Diarrhea
Phase II study demonstrates safety and efficacy of vaccine containing heat-labile enterotoxin
THURSDAY, June 12 (HealthDay News) -- A skin patch vaccine containing heat-labile enterotoxin from enterotoxigenic Escherichia coli may either help prevent traveler's diarrhea or lessen its effects, according to research published online June 12 in The Lancet.
Sarah A. Frech, of IOMAI Corporation in Gaithersburg, Md., and colleagues recruited 201 healthy adults aged 18 to 64 who planned to travel to Mexico or Guatemala for a phase II trial. Before travel, the subjects were randomly assigned to apply two patches given two to three weeks apart that contained either heat-labile enterotoxin or placebo.
Of the 170 subjects who were analyzed after travel, the researchers found that the diarrhea rate was significantly lower in the active-patch group than in the placebo group (15 percent versus 22 percent). They also found that the rate of moderate-to-severe diarrhea was lower in the active-patch group (5 percent versus 21 percent) and observed that active-patch recipients had shorter episodes of diarrhea (0.5 days versus 2.1 days) and fewer loose stools (3.7 versus 10.5 per day).
"In addition to the biological rationale for delivering antigen to the skin, the transcutaneous patch lends itself to a simple and needle-free application, use of the vaccine outside the cold chain, and has been designed to be suitable for both travelers and use in the developing world," the authors conclude. "This study suggests that transcutaneous immunization with heat-labile enterotoxin in a patch could protect travelers against this common, debilitating ailment but the recorded efficacy will need confirmation in a phase III trial."
Several of the study authors are shareholders in IOMAI Corp.