Hepatitis A

Hepatitis A is an enterically transmitted viral disease, highly endemic throughout the developing world, where standards of sanitation are poor. In developing countries, hepatitis A virus (HAV) is usually acquired during childhood. Most frequently the children either are asymptomatic or they develop mild infections, resulting in the development of life-long immunity.

Transmission

Transmission may occur by direct person-to-person contact, from contaminated water, ice, or shellfish harvested from sewage-contaminated water, or from fruits, vegetables or other foods which are eaten uncooked, but which may become contaminated during handling.

Symptoms

Symptoms include fatigue, fever, loss of appetite, nausea, dark urine, jaundice, vomiting, aches and pains, and light stools. No specific therapy is available.
For travelers to developing countries, risk of infection increases with the duration of travel, and is highest for those who live in or visit rural areas, trek in back country, or frequently eat or drink in settings of poor sanitation.

Risk

Travelers are at high risk for Hepatitis A, especially if travel plans include visiting rural areas and extensive travel in the countryside, frequent close contact with local persons, or eating in settings of poor sanitation.

A study has shown that many cases of travel-related hepatitis A occur in travelers to developing countries with "standard" itineraries, accommodations, and food consumption behaviors.

Prevention

In developing countries, travelers should minimize their exposure to hepatitis A and other enteric diseases by avoiding potentially contaminated water or food. Travelers should avoid drinking water (or beverages with ice) of unknown purity and eating uncooked shellfish or uncooked fruits or vegetables that are not peeled or prepared by the traveler.

Hepatitis A virus is inactivated by boiling or cooking to 185°F or 85° C for 1 minute, therefore eating thoroughly cooked foods and drinking only treated water serve as general precautions. Cooked foods may serve as vehicles for disease if they are contaminated after cooking. Adequate chlorination of water as recommended in the U.S. will inactivate HAV.

Vaccination

This is a very infectious virus, so if there is risk of exposure, injection with gammaglobulin (IG) or vaccination with Havrix -- the hepatitis A vaccine currently licensed for use in the US -- is recommended. Gammaglobulin is an injection of antibodies to hepatitis A, providing immunity for a limited time. Havrix is a vaccine which causes the traveler to develop his or her own antibodies, giving long-lasting immunity.

Hepatitis A vaccine is recommended for persons who plan to travel repeatedly or reside for long periods of time in intermediate or high risk areas. Immune globulin should be used for travelers under 2 years of age, and is recommended for any person who desires only short term protection.

Recommendations

CDC recommends hepatitis A vaccine or IG for protection against hepatitis A. For travelers over 18 years of age, hepatitis A vaccine should be given in a two dose series with the second dose administered 6-12 months after the first. For children and adolescents (2-18 years), a three dose series of hepatitis A vaccine is recommended; the second dose is given 1 month after the first dose and the third dose 6-12 months after the first dose.

Travelers can be considered to be protected four weeks after receiving the initial vaccine dose. IG should also be given if vaccine is administered less than four weeks before travel. The vaccine series must be completed for long-term protection.

Diseases