I’m Dr Karen Wong, with the Enteric Diseases Epidemiology Branch at the Centers for Disease Control and Prevention (CDC). I’m pleased to be speaking with you today as part of the CDC Expert Video Commentary series on Medscape. Today I’m discussing the risk for cholera in travelers, how it can be prevented, and use of the new vaccine.
The US Food and Drug Administration licensed a new cholera vaccine for use in travelers, the first to be available since the 1990s. Although cholera is rare in US travelers, CDC recommends that adults traveling to certain areas be vaccinated. The vaccine is not currently licensed for children.
A study of cholera patients reported in the United States found that about 80% of infections were associated with international travel. Ninety cases linked to travel were reported over 10 years. These patients had traveled to Africa, Asia, or the Caribbean. The most common reason for travel was to visit friends and relatives. Other reasons included medical missions or other relief work, tourism, and business.
Here are some recommendations to give patients:
- The mainstay of cholera prevention should be adherence to safe food and water precautions.
- Travelers going to cholera-affected areas should be counseled to eat only food that is cooked and served hot, and to drink only beverages from sealed bottles or cans.
- Careful hand hygiene should also be emphasized.
Vaxchora™ is a single-dose oral cholera vaccine recommended for adults aged 18-64 years who are traveling to an area of active toxigenic Vibrio cholerae O1 transmission. For the most up-to-date information about areas of cholera transmission, visit CDC’s Travelers’ Health website.
In clinical trials, Vaxchora reduced the risk for severe diarrhea after a cholera challenge by 90% at 10 days after vaccination, and by 80% at 3 months after vaccination. The duration of protection of Vaxchora beyond 3-6 months is not known at this time. The vaccine should be administered at least 10 days before potential exposure to cholera. In clinical trials, adverse reactions were uncommon and included fatigue, headache, abdominal pain, nausea and vomiting, diarrhea, and lack of appetite.[2,3]
Cholera vaccination may be especially important for those travelers with higher risk for exposure to cholera or higher risk for poor outcomes. Certain travelers to cholera-affected areas may be at high risk for cholera. These include people who are traveling to provide humanitarian aid in cholera outbreak settings, those visiting friends and relatives, those staying for a long time, or those with limited access to safe food and water. People with blood type O; low gastric acidity; and certain medical conditions that would not tolerate dehydration well, such as heart or kidney disease, may have worse outcomes if infected. Cholera can be rapidly fatal if untreated, and those without ready access to medical care may be at high risk for poor outcomes.
When discussing cholera vaccine with travelers, explain that cholera is rare but can be severe, and emphasize the need to focus first on food and water precautions, even for those who are vaccinated against cholera. Discuss risk factors for exposure to cholera and risk factors for poor outcomes if infected, as well as the appropriate treatment (such as oral rehydration salts) and when to seek medical care.
This vaccine can cost more than $250, and travelers may have to pay out of pocket if their insurance does not cover travel vaccines.
Cholera can be a serious or even fatal disease, but it is rare and treatable when rehydration is started as soon as possible. Prevention strategies include safe food and water precautions, careful hand hygiene, and vaccination. Vaccination is recommended for adult travelers going to areas of active cholera transmission. It may be especially important for travelers at higher risk for exposure to cholera or at higher risk of having a poor outcome from infection.
Karen Wong, MD, MPH, is a medical officer in the Division of Foodborne, Waterborne, and Environmental Diseases at CDC and an officer in the US Public Health Service. Her work focuses on surveillance of enteric diseases. She is board-certified in internal medicine and also works as a hospitalist at Emory University Hospital.