08-20-2009, 12:27 AM
Preventing Hepatitis A Infection While Traveling
Although hepatitis A is becoming more common in developed areas such as the US, Canada, Western Europe, Japan, Australia and New Zealand, it occurs much more frequently in areas of the world that are less developed, such as Central America and Africa. The risk of infection increases with length of stay, visits to rural areas, and eating in places that likely have poor sanitation, such as food stands on the street or restaurants that appear not to be kept clean.
Unfortunately, since we can never know for sure where the virus lurks, even the most cautious tourist can be unavoidably exposed. Most episodes of infection are spread by infected food handlers who might not yet have any sign of illness. By failing to wash their hands adequately after a bowel movement, such disease carriers can spread the virus to food in the preparation and serving process. Transmission can also occur by drinking water that has been contaminated by sewage, or by eating contaminated raw shellfish.
For protection, travelers should receive a hepatitis A vaccine or an injection of immune globulin (previously called gamma globulin), which contains antibodies against the hepatitis A virus. The vaccine is given as a single dose, preferably at least two weeks prior to travel, although the vaccine should still offer protection even if given just before departure. The initial injection can be followed by a booster dose in 6-12 months with resulting protection estimated to last 10-20 years. Side effects have been reported to be minimal and include local soreness at the injection site, headache and fatigue.
Since immune globulin is not a vaccine, the antibody levels it confers will decline with time. For the greatest protection, this injection should be given close to the time of departure, ideally within 3-5 days. Depending on the dose given, this protection can last from three to five months. Immune globulin shots are given in the buttock and usually are associated with minimal local side effects, such as soreness at the injection site. There is no evidence that immune globulin can transmit any disease, and it can be safely given to pregnant women. At various times in the last few years immune globulin has been difficult to obtain due to manufacturing shortages.
Persons who are known to have had hepatitis A in the past already have antibodies to the disease - which means they are immune - and do not need further protection. A blood test is available to confirm this immunity if uncertainty exists. Frequent or long-term travelers should definitely consider receiving the hepatitis A vaccine rather than immune globulin.
Gary P. Barnas, MD
Associate Professor
General Internal Medicine
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