Travelers Diarrhea, Is There a Vaccine For That?

Travelers’ diarrhea is the most common travel-related illness and it can occur anywhere, says the Centers for Disease Control and Prevention (CDC).

Although it is rarely life-threatening, Travelers’ diarrhea (TD) can cause discomfort, stress, and ruin a trip. In otherwise healthy adults, diarrhea is rarely serious or life-threatening.

Unfortunately, there is not a preventive vaccine available for TD.

The CDC said on October 8, 2019, TD attack rates range from 30 to 70 percent of travelers, depending on the destination and season of travel. Most of the 10 million travelers’ diarrhea cases each year are the result of bacterial infection and are short-lived as well as self-limited. 

Prolonged diarrheal symptoms can be caused by immunosuppression, sequential infection with diarrheal pathogens, and infection with protozoan parasites.

The highest-risk destinations are in Asia (except for Japan and South Korea), followed by the Middle East, Africa, Mexico, and Central and South America.

If you are traveling overseas, some airlines check for visibly sick passengers in the waiting area and during boarding. If you look like you may be sick, the airline may not let you get on the plane. 

And, if you’re pregnant, be sure to talk with your doctor before making any travel decisions. Pregnant women over 36 weeks may not be able to travel by plane. Each airline has its own policy about rescheduling flights because of an illness.

And, if you’re traveling with a weakened immune system, make sure you talk to your doctor and take extra steps to ensure a safe and healthy trip.

Children on trips to high-risk destinations can contract TD as well, with elevated risk if they are visiting friends and family. Infants and younger children with TD are at higher risk for dehydration, which is best prevented by the early initiation of oral rehydration

Some travel-related illnesses may not cause symptoms until after you get home. Persistent diarrhea can make you lose nutrients and is often caused by a parasitic infection that might need to be treated with special drugs. 

If you are not feeling well after you come home, you may need to see a healthcare provider.

Despite the frequency of TD, there is no international consensus on its prevention. But, the CDC says you can take steps to avoid traveler’s diarrhea, such as:

• Choose food and drinks carefully:  Eat only foods that are cooked and served hot. Avoid food that has been sitting on a buffet. Eat raw fruits and vegetables only if you have washed them in clean water or peeled them. Only drink beverages from factory-sealed containers, and avoid ice because it may have been made from unclean water.
• Wash your hands:  Wash your hands often with soap and water, especially after using the bathroom and before eating. If soap and water aren’t available, use an alcohol-based hand sanitizer. In general, it’s a good idea to keep your hands away from your mouth.

How to treat traveler’s diarrhea:

• Drink lots of fluids:  If you get diarrhea, drink lots of fluids to stay hydrated. In serious cases of travelers’ diarrhea, oral rehydration solution—available online or in pharmacies in developing countries—can be used for fluid replacements.
• Take over-the-counter drugs: Several drugs, such as loperamide, can be bought over-the-counter to treat the symptoms of diarrhea. These drugs decrease the frequency and urgency of needing to use the bathroom and may make it easier for you to ride on a bus or airplane while waiting for an antibiotic to take effect.
• Only take antibiotics if needed:  Your doctor may give you antibiotics to treat traveler’s diarrhea, but consider using them only for severe cases. Antibiotics are effective in reducing the duration of diarrhea by about a day in cases caused by bacterial pathogens that are susceptible to the particular antibiotic prescribed. However, there are concerns about adverse consequences of using antibiotics to treat TD. If you take antibiotics, take them exactly as your doctor instructs. If severe diarrhea develops soon after you return from your trip, see a doctor and ask for stool tests so you can find out which antibiotic will work for you.

Many international travelers ask if the oral cholera vaccine be routinely recommended to prevent traveler’s diarrhea. 

According to various studies and randomized controlled trials evaluating the oral cholera vaccine for TD, they did not show a benefit and do not recommend its routine use.

But, the results from a 2013 study suggest that Whole‐cell/recombinant‐B‐subunit (WC/rBS) cholera vaccination of travelers to high-risk areas is associated with an absolute reduction of 28 percent in the risk of all-cause TD diarrhea.

Because the WC/rBS vaccine (Dukoral) was only approved for cholera prophylaxis in Spain, this study only included travelers to zones where cholera is endemic, in order to achieve a sufficient sample. Therefore, it was impossible to estimate the vaccine’s actual effectiveness.

And recently, an August 2019 workshop brought together many of the experts in the field of enteric disease vaccine development. Each setting offers unique opportunities and challenges for endpoint determination. 

These experts hoped their workshop report will facilitate vaccine developers in selecting an optimal endpoint for use in their product development.

Previously, the US Food and Drug Administration approved a single-dose oral cholera vaccine (CVD 103-HgR), Vaxchora, in June 2016,

The Advisory Committee on Immunization Practices voted to recommend cholera vaccine for adult (18–64 years) travelers to an area of active transmission is defined as an administrative subdivision where cases have been reported within the past year.

Traveller's Diarrhea news published by Vax-Before-Travel