With the weather becoming warmer, many of us have started making travel plans. If you are travelling outside of Canada, it’s important to know what vaccinations you need before you go. The purpose of travel vaccines is to minimize your risk of a number of diseases, which varies depending upon itinerary, duration of travel, and rural versus urban travel. I recommend visiting a travel clinic or your family physician at least 4-6 weeks before you travel.
Today, I will focus on traveller’s diarrhea and its vaccine because diarrhea is the most common illness among travellers. It affects up to 55% of individuals who tour developing countries and many of these persons experience discomfort and inconvenience. Rarely is it life threatening, in fact, most episodes are mild and self-limited.
Up to 75% of cases of traveller’s diarrhea are caused by bacteria. The most frequent bacteria for traveller’s diarrhea is enterotoxigenic Escherichia coli (ETEC). ETEC counts for about 25-50% of travellers diarrhea.
Dukoral is recommended for adults and children 2 years of age and older who are travelling to high risk areas such as Latin America, Africa, and Southeast Asia. Dukoral works by introducing very small amounts of dead cholera bacteria and nontoxic components of cholera toxin into the body. The cholera toxin is very similar to the toxin produced by ETEC, the bacteria that causes most cases of travellers diarrhea. With this preventative measure, the body’s defences against cholera toxin will also work against the ETEC toxin and thus, in theory, it would protect travellers from diarrhea.
The cost of Dukoral is around $100 for two doses. The two doses of oral vaccine should be one to six weeks apart, with the last dose taken at least one week before the trip. Protection against diarrhea caused by ETEC starts about one week after the second dose and lasts for about three months. Protection against cholera starts about one week after the second dose and lasts for about two years for patients over 6 years of age. A booster dose is required beyond the months for traveller’s diarrhea and 6 months (for patients 2 to 6 years of age) or 2 years (for patients over 6 years of age) for cholera. Allergic reactions and side effects such as abdominal pain, diarrhea, fever, nausea, and vomiting may occur. *It is not recommended during pregnancy.*
Dukoral does not treat travellers diarrhea once it develops and does not prevent diarrhea caused by other organisms. Not everyone who gets vaccinated will be fully protected.
Durkoral’s efficacy is about 86% for epidemic cholera and approximately 25% for overall travellers diarrhea. It protects against Vibrio cholera serogroup 01 but does not protect against cholera caused by V. cholerae 0139 or other species of Vibrio. The number needed to prevent 1 case of travellers diarrhea is 10.
Precautions to avoid contaminated foods or liquids should be taken. One tip to effectively lower your risk of travellers diarrhea is to eat only foods or drinks that follow the Four P’s rule: peelable, packaged, purified, or piping hot.
In Summary, indications for Durkoral to prevent traveller’s diarrhea are limited because:
- Most episodes of traveller’s diarrhea are mild and self-limited.
- Thereaputic options (oral rehydration, dietary management, anti-motility and antibiotic treatment) are available if prevention fails.
- The overall protection provided by Dukoral against travellers diarrhea is expected to be approximately 25%.
- Vaccinated travellers may have a false sense of security and may not be as strict in observing food and water precautions.
* References from Public Health Agency of Canada
