Travelers’ Diarrhea Vaccine
Scientists from The University of Texas School of Public Health testing a travelers’ diarrhea vaccine have found that patients getting the vaccine were significantly less likely to suffer from significant diarrhea than those who got the placebo, based on research in this week’s Lancet. The vaccine is a patch-based vaccine in Phase 2 testing (from the Iomai Corporation).
The study followed 170 healthy travelers aged 18-64 traveling to Mexico and Guatemala. Researchers found that only 3 of the 59 individuals who received the novel vaccine developed moderate or severe diarrhea. In the group that got the placebo vaccine two dozen of the 111 suffered from moderate or severe diarrhea. Only one patient in the vaccine group had severe diarrhea.
The Iomai vaccine patch could fundamentally alter the way we approach prevention of travelers’ diarrhea which previously had few effective treatments according to Herbert L. DuPont, M.D. director of the Center for Infectious Diseases at The University of Texas School of Public Health.
The Trek Study was conducted in cooperation with UT Houston, the Johns Hopkins School of Public Health and others. The volunteers were given either two doses of the vaccine patch or a placebo. Travelers wrote diaries and received checkups while traveling. The study evaluated the safety of the vaccine and the incidence of enterotoxigenic E. coli (ETEC) bacteria – which is the most common bacteria that leads to travelers’ diarrhea. Researchers noted that no vaccine-related serious side effects were observed.
Of the few vaccinated patients who became sick, the diarrhea was mild and lasted only part of a day. Patients in the placebo vaccine group suffered two days or more of illness and had more than twice as many bowel movements. An additional positive finding was that new-onset irritable bowel syndrome was three times less likely in vaccine recipients.
This year, approximately 55 million international travelers will visit countries where bacteria that cause travelers’ diarrhea are endemic, particularly Africa, Asia and Latin America, and about 20 million of those will develop travelers’ diarrhea.
Patients who suffer a case of travelers’ diarrhea are also at increased risk of later developing irritable bowel syndrome, a chronic illness characterized by pain, diarrhea or constipation. Diarrheal diseases also harm many children in developing countries, where diarrhea caused by enterotoxigenic E. coli made 210 million children sick annually (killing 380,000 of these children).
Bacterial diarrhea is a serious medical problem both for children and adult travelers. The new patch vaccine technology is an advance in vaccine delivery according to Gregory Glenn, M.D. from Iomai Corporation’s chief science officer.
Iomai will initiate a Phase 3 trial of the needle-free vaccine patch vaccine in 2009. If the phase 3 trials are successful, the Iomai vaccine patch would be the first vaccine for travelers’ diarrhea available in the United States.
