Testing of Vaccine for Traveler’s Diarrhea
Traveler’s diarrhea affects millions of people that travel to third world countries every year. It develops after ingestion of contaminated food or water. While it is rarely fatal and generally clears on its own, people affected by it will generally spend a day or two in bed. They will need to cut back their activities. It can also cause more serious illnesses in children and pregnant women.

A clinical trial was conducted to study the effectiveness and risks of a potential vaccine, heat-labile toxins from E. coli (LT). The study, published in the Lancet , showed positive results in reducing the incidence or duration of traveler’s diarrhea.

About the Study
The study followed 201 healthy adults 18-64 years of age planning a trip to Mexico or Guatamala from the US. The participants were randomly assigned to one of two groups:

  • Group 1 received two patches with 37.5 mug of LT
  • Group 2 received two patches with a placebo
The patches were given 2-3 weeks before travel. The travelers tracked stool output and provided stool samples if diarrhea occurred.

There was less, but not a significant, difference for the occurrence of diarrhea in both groups (15% compared to 22%). But the travelers that received the vaccine had less severe diarrhea (2% compared to 11%) and it did not last as long (0.5 days compared to 2.1 days) than the group that received the placebo patch. There were no negative side effects reported.

How Does This Affect You?
When traveling to developing countries follow safety guidelines to avoid traveler’s diarrhea . This includes avoiding raw foods from street vendors, avoiding raw or undercooked meats and seafood, eating foods that are fully cooked and served hot, avoiding salads or unpeeled fruit, and not drinking tap water or adding ice cubes. If you must drink local water, boil it first.

The vaccine is still being evaluated and not available to the public. Talk to your doctor if you are planning a trip to a developing country and are concerned about traveler’s diarrhea.

American Academy of Family Physicians

Center for Disease Control and Prevention

Frech SA, Dupont HL, Bourgeois AL, et al. Use of a patch containing heat-labile toxin from Escherichia coli against travellers' diarrhoea: a phase II, randomised, double-blind, placebo-controlled field trial. Lancet . 2008 Jun 14;371(9629):2019-25.

Traveler’s diarrhea. EBSCO Health Library website. Available at: http://www.ebscohost.com/thisMarket.php?marketID=14 . Accessed July 11, 2008.

Last Reviewed July 2008

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