ICAAC: Vaccine in Works to Block Traveler's Diarrhea -... -
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Last Visited: 4/22/2006
"We feel this is a very promising concept for a vaccine for traveler's diarrhea," said A. Louis Bourgeois, Ph.D., of the Center for Immunization Research at the Johns Hopkins Bloomberg School of Public Health.
The vaccine is targeted against the major cause of traveler's diarrhea, enterotoxigenic Escherichia coli, Dr. Bourgeois and colleagues reported at the Interscience Conference on Antimicrobial Agents and Chemotherapy.
They administered it to more than 700 students on their way to Spanish- language immersion classes in Guatemala and Mexico.Another 700 participants were given placebo.
The vaccine contains formalin-killed E. coli whole cells plus the B-subunit of the cholera enterotoxin.The vaccine is taken in a two-dose regimen seven to 21 days apart.Not surprisingly, Dr. Bourgeois said that traveler's who mounted the strongest response to introduction of the vaccine were best protected.If, on arrival in the place of study a patient had immunoglobulin A titers to E. coli that were more than 1,358 it was assumed that the vaccine had "taken."
Of the 700 people who were given the active agent, 156 developed sufficient responses to have been considered vaccinated, Bourgeois said.They were matched against 195 of the placebo students.
Among this subgroup, he said, the vaccine was about 77% effective in preventing diarrhea in the students, and even among those students who came down with E. coli -caused diarrhea; the cases were relatively mild compared to those who were taking the placebo.
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Dr. Bourgeois is working in collaboration with Johns Hopkins and SBL Vaccines of Solna, Sweden, on the vaccine."The further development of this promising enterotoxigenic E. Coli vaccine is warranted and should be pursued," he said.