Before I left for my first trip to Laos, I was advised by my doctor that I needed a myriad of different vaccinations. My arm was certainly sore after I left the clinic that day! I wondered, of course, were these shots really necessary? Would Laos be a dangerous place teeming with bacteria, viruses and rabid wildlife? Now that I have the medicine in my veins, it’s too late for me to worry about it, but I wanted to provide newcomers with this information so that they can choose for themselves which vaccinations they really need, and which they don’t.
The following are the recommended vaccinations for a visit to Laos:
Hepatitis A vaccine is recommended for all travelers over one year of age. It should be given at least two weeks (preferably four weeks or more) before departure. A booster should be given 6-12 months later to confer long-term immunity. Two vaccines are currently available in the United States: VAQTA (Merck and Co., Inc.) (PDF) and Havrix (GlaxoSmithKline) (PDF). Both are well-tolerated. Side-effects, which are generally mild, may include soreness at the injection site, headache, and malaise.
Older adults, immunocompromised persons, and those with chronic liver disease or other chronic medical conditions who have less than two weeks before departure should receive a single intramuscular dose of immune globulin (0.02 mL/kg) at a separate anatomic injection site in addition to the initial dose of vaccine. Travelers who are less than one year of age or allergic to a vaccine component should receive a single intramuscular dose of immune globulin (see hepatitis A for dosage) in the place of vaccine.
Typhoid vaccine is recommended for all travelers, with the exception of short-term visitors who restrict their meals to major restaurants and hotels, such as business travelers. It is generally given in an oral form (Vivotif Berna) consisting of four capsules taken on alternate days until completed. The capsules should be kept refrigerated and taken with cool liquid. Side-effects are uncommon and may include abdominal discomfort, nausea, rash or hives. The alternative is an injectable polysaccharide vaccine (Typhim Vi; Aventis Pasteur Inc.) (PDF), given as a single dose. Adverse reactions, which are uncommon, may include discomfort at the injection site, fever and headache. The oral vaccine is approved for travelers at least six years old, whereas the injectable vaccine is approved for those over age two. There are no data concerning the safety of typhoid vaccine during pregnancy. The injectable vaccine (Typhim Vi) is probably preferable to the oral vaccine in pregnant and immunocompromised travelers.
Japanese encephalitis vaccine is recommended for those who expect to spend a month or more in rural areas and for short-term travelers who may spend substantial time outdoors or engage in extensive outdoor activities in rural or agricultural areas, especially in the evening. Japanese encephalitis is believed to occur throughout Laos. The disease is transmitted by mosquito bites, probably from May through October. The recommended vaccine is IXIARO , given 0.5 cc intramuscularly, followed by a second dose 28 days later. The series should be completed at least one week before travel. The most common side effects are headaches, muscle aches, and pain and tenderness at the injection site. Safety has not been established in pregnant women, nursing mothers, or children under the age of two months. In addition to vaccination, strict attention to insect protection measures is essential for anyone at risk.
Hepatitis B vaccine is recommended for all travelers if not previously vaccinated. Two vaccines are currently licensed in the United States: Recombivax HB (Merck and Co., Inc.) (PDF) and Engerix-B (GlaxoSmithKline) (PDF). A full series consists of three intramuscular doses given at 0, 1 and 6 months. Engerix-B is also approved for administration at 0, 1, 2, and 12 months, which may be appropriate for travelers departing in less than 6 months. Side-effects are generally mild and may include discomfort at the injection site and low-grade fever. Severe allergic reactions (anaphylaxis) occur rarely.
Rabies vaccine is recommended for travelers spending a lot of time outdoors, for travelers at high risk for animal bites, such as veterinarians and animal handlers, for long-term travelers and expatriates, and for travelers involved in any activities that might bring them into direct contact with bats. Children are considered at higher risk because they tend to play with animals, may receive more severe bites, or may not report bites. A complete preexposure series consists of three doses of vaccine injected into the deltoid muscle on days 0, 7, and 21 or 28. Side-effects may include pain at the injection site, headache, nausea, abdominal pain, muscle aches, dizziness, or allergic reactions.
Any animal bite or scratch should be thoroughly cleaned with large amounts of soap and water and local health authorities should be contacted immediately for possible post-exposure treatment, whether or not the person has been immunized against rabies.
Measles–mumps–rubella vaccine: two doses are recommended (if not previously given) for all travelers born after 1956, unless blood tests show immunity. Many adults born after 1956 and before 1970 received only one vaccination against measles, mumps, and rubella as children and should be given a second dose before travel. MMR vaccine should not be given to pregnant or severely immunocompromised individuals.
Cholera vaccine is not generally recommended, even though cholera occurs in Laos, because most travelers are at low risk for infection. Two oral vaccines have recently been developed: Orochol (Mutacol), licensed in Canada and Australia, and Dukoral, licensed in Canada, Australia, and the European Union. These vaccines, where available, are recommended only for high-risk individuals, such as relief workers, health professionals, and those traveling to remote areas where cholera epidemics are occurring and there is limited access to medical care. The only cholera vaccine approved for use in the United States is no longer manufactured or sold, due to low efficacy and frequent side-effects.
Polio vaccine is not recommended for any adult traveler who completed the recommended childhood immunizations. In October 2000, the World Health Organization certified that polio had been eradicated from the Western Pacific region.
Yellow fever vaccine is required for all travelers arriving from a yellow-fever-infected country in Africa or the Americas, but is not recommended or required otherwise. Yellow fever vaccine (YF-VAX; Aventis Pasteur Inc.) (PDF) must be administered at an approved yellow fever vaccination center, which will give each vaccinee a fully validated International Certificate of Vaccination. Yellow fever vaccine should not in general be given to those younger than nine months of age, pregnant, immunocompromised, or allergic to eggs.