If you're planning an overseas trip, some vaccinations may be in order. But think ahead. Some vaccinations should be given a month — or even six months — before you depart on an overseas trip. While any physician or clinic can administer some of the necessary vaccines, it may be advisable to visit a specialist in travel medicine. The staff at travel clinics can give specific advice about the areas you plan to visit and they usually have all the necessary vaccines in stock. They also can prescribe medications to protect against malaria and diarrhea.
If you are advised that your travels will necessitate certain vaccines, you should know something about them as well as some of the microbes you may be exposed to while out of the country. Some of the more common ones are listed at right:
Hepatitis is a viral infection of the liver. There are five forms, types A, B, C, D and E, each caused by a different virus.
Vaccine: Available and highly recommended, with first shot administered at least 4 weeks before a trip. A single shot protects for only six months, but it is estimated that a follow-up booster administered at six to 12 months will extend protection to 10 years.
Vaccine: Children now receive hepatitis B vaccine as part of their routine childhood immunizations. However, adults who have not been previously vaccinated may want to do so, especially before long-term overseas travel. If possible, you should receive the first vaccination at least six months before you depart, because a series of three shots is required before you have full protection against the virus.
Hepatitis C and D
Acquired through contact with blood and body fluids.
Acquired from contaminated water, and possibly through contaminated food.
Diphtheria is still prevalent throughout the world. Tetanus occurs worldwide in unimmunized individuals. Pertussis has become more widespread in the last several years. It is more common in childhood. It is especially common in countries where immunization rates are low.
Polio had been wiped out in all but four Asian and African countries.
Vaccine: Diphtheria, tetanus, pertussis and polio are part of the normal childhood vaccination schedule, and all children should be up to date before traveling abroad.
A diphtheria/tetanus booster is recommended for adults, either every 10 years, or when heading to developing countries.
A one-time pertussis vaccine is recommended for all adults and definitely should be done prior to any travel.
Consider a polio booster if travelling to Asia or Africa.
Measles, mumps and rubella are now uncommon in the United States, with only a few hundred reported cases occurring each year.
Vaccine: Measles, mumps and rubella vaccinations are part of the normal childhood vaccination schedule. All children should be up to date on all of their vaccinations before heading abroad. Adults born before 1957 usually have been exposed to measles and mumps and generally don't need to be vaccinated. However, this is not true for rubella. People born before 1957 who have not been vaccinated for rubella should be immunized before travel. The U.S. government's Centers for Disease Control and Prevention (CDC) advises that adults born during or after 1957 should make sure they have had two doses of the MMR (measles, mumps, rubella) vaccine, and if they haven't, to consider getting a single dose.
Yellow fever is a virus carried by mosquitoes in tropical parts of Africa and South America. While it's a very serious disease, it's not a common cause of infection in travelers. However, the CDC recommends the yellow fever vaccination for travelers to many countries in Africa and South America. In addition, some countries require certification that the vaccine has been administered for all travelers, while other countries require this certification for those travelers who are arriving from countries where the disease is present. For more information, read the CDC's information on yellow fever vaccination requirements.
Vaccine: Should be received at least 10 days before travel, and it's good for 10 years. Available for adults and children older than 9 months. Pregnant women and people allergic to eggs should not receive this vaccine.
Typhoid fever is caused by consuming food or water contaminated with Salmonella typhi bacteria. It's common outside the industrialized world, with an estimated 16 million cases occurring each year, causing about 600,000 deaths. Most of the 400 cases seen in the United States each year result from overseas travel. Symptoms include fever, headache, abdominal pain, loss of appetite and fatigue. Serious or untreated cases can be fatal. Ciprofloxacin, which also is used to treat other, less serious forms of diarrhea; ceftriaxone; ampicillin; or trimethoprim-sulfamethoxazole can be used to treat typhoid.
Vaccine: Two types in general use: 1) four capsules of the live vaccine are taken by mouth two days apart, two weeks before trip, providing five years of protection; 2) a single injection of the non-living vaccine given one week before travel will provide two years of protection against typhoid fever.
Japanese encephalitis got its name because it was first found in Japan. However, it is now rare there, but it is endemic in rural China and Southeast Asia. No specific treatment is available. Even though people who develop encephalitis (inflammation of the brain) have about a 25-percent chance of dying of the disease, only a small percentage of those who are bitten by an infected mosquito will become ill. In fact, only a handful of cases have been reported among American travelers abroad. Therefore, despite its potential to cause death in rare cases, it should not be a big concern to most travelers because outbreaks are seasonal and usually confined to specific rural areas.
Vaccine: An effective vaccine is available for people 17 years of age and older. Two doses are given over a one-month period. However, the vaccine is not generally given to travelers, but may be appropriate for those who will spend extended periods of time in rural areas of Asia. It is best to check with a travel-medicine expert for information on where Japanese encephalitis outbreaks are occurring. Information on Japanese encephalitis outbreaks also is available from the CDC.
Tick-borne encephalitis (TBE), also known as spring-summer encephalitis, is widespread in both western and eastern Europe. It is caused by a virus spread by the bite of tiny ticks in the Ixodes family, which is the same group that carries Lyme disease. TBE also can be acquired by drinking unpasteurized milk from infected cows, goats or sheep.
As with Lyme disease, infections coincide with peak tick season, April through August. Being a viral disease, it is not curable with antibiotics, though, as is the case with Lyme disease and other bacterial tick-borne infections. The TBE vaccine, which is only available in Europe, is recommended for those who plan on an extended stay in the endemic areas, especially if they will be spending time in forests, fields, or pasture lands.
Symptoms include headache, fever, flulike symptoms and, in some cases, severe neurological symptoms such as seizures, paralysis and coma.
Vaccine: A TBE vaccine is available in Europe, but is not licensed in the United States. Longer-term visitors to Europe can inquire locally as to the advisability of obtaining the vaccine. Unvaccinated people who spend time in forests and fields should use general tick-protection measures, including wearing long pants and long-sleeve shirts, regular inspection for ticks, and use of DEET insect repellants on skin and clothing, or permethrin, which is applied to clothing and will repel and kill ticks.
Meningococcal meningitis develops when the Neisseria meningitidis bacteria cause an infection of the lining and the fluid surrounding the brain and spinal cord. Without prompt treatment with antibiotics, there is a high fatality rate. Although outbreaks can occur anywhere in the world, they more commonly occur in group settings, such as college dormitories, hospitals and nursery schools.
Travelers should be aware that it is particularly prevalent in the "meningitis belt" of Africa, which runs from Mali on the west to Ethiopia on the east. The disease is most frequently acquired during the dry season, December through June, particularly in the savanna areas.
Vaccine: Routine vaccination is now recommended for all adolescents. Adults and younger children traveling to any area of the world known to have an outbreak of meningococcal meningitis should be vaccinated. Required for pilgrims on Hajj, and other visitors to Saudi Arabia. Recommended for people visiting the meningitis belt of Africa during the dry season, especially if the trip involves extended visits to rural areas.
Rabies is a viral infection that is transmitted to humans by animal bites. In developing countries, it is most commonly spread by dog bites. In the United States, bats, raccoons and other wild animals usually transmit rabies. If it is not treated promptly with immunoglobulin and post-exposure vaccine, it will attack the nervous system. At this stage, it is invariably fatal.
When traveling abroad, stay especially clear of stray dogs and cats and any animal that seems particularly lethargic or aggressive.
Seek immediate medical attention for all animal bites or scratches from bats. Contact the U.S. Embassy for advice on the safety and adequacy of local post-exposure treatments.
Vaccine: Pre-exposure rabies vaccination can be considered for travelers planning visits to areas where the risk of bites is high. The benefit for people vaccinated in advance of a rabies exposure is that they will not need to get immunoglobulin, which can be hard to obtain in the developing countries where risk of rabies is highest. Even those who receive the pre-exposure vaccine still will need additional post-exposure vaccination in cases of suspected rabies exposure.
It may be inviting to plunge into a cool lake or river while baking away in the tropics, but don't do it. Tropical freshwater often contains parasitic larvae, which cause a disease called schistosomiasis. It's a common malady that currently infects about 200 million people worldwide, causing an estimated 200,000 deaths per year. Human waste carries the eggs of the worm into lakes, ponds or canals, where they hatch and their larvae take up residence in snails. The infective forms of the parasites are released by the snails, and they then can enter the skin of people who swim or wade in the water. Once inside the body, the larvae grow into large flatworms, also known as flukes, which can infest the liver, kidneys, and other organs.
Where Are The Schistosomiasis Zones?
Most people have few symptoms of infestation with schistosomiasis, and when symptoms do occur, they are mostly the result of the body's immune response to the parasite. Some patients will develop an intensely itchy rash within one day of the exposure to the contaminated water. Fever, chills, cough and muscle aches also may occur a month or two after a person first acquires the infection. Patients with large numbers of the parasites, from repeated exposure over many years, may develop other symptoms of the disease, including abdominal pain, bloody diarrhea and bloody urine. Untreated schistosomiasis may result in bladder cancer or problems with the liver or colon. In rare cases, there is damage to the brain or spinal cord. If you suspect you might be infected, contact your physician, who can order tests and prescribe medicine.
Cholera is a diarrheal disease caused by infection with the bacteria Vibrio cholerae. Those who become ill develop profuse, watery diarrhea that rapidly can cause severe dehydration and death in untreated patients. An estimated 5.5 million cases of cholera occur worldwide annually, resulting in about 100,000 deaths each year. Cholera usually is contracted by consuming contaminated food or water. Fish and shellfish also can be sources of the microbe. Use standard precautions against contaminated food and water to avoid infection.
Any person suffering severe diarrhea, whatever the cause, should seek medical attention immediately. If medical care is not available, use oral rehydration solution (ORS) to prevent or treat dehydration. If ORS is unavailable, an acceptable alternative can be produced by mixing one-half teaspoon of salt, one-half teaspoon of baking soda, and four tablespoons of sugar with one liter of clean water. Bottled sports drinks do not contain the appropriate concentrations of salt and sugar to allow maximal absorption of water by the intestine. Drink enough so that you produce light-colored urine every three to seven hours.
Vaccine: There is no licensed cholera vaccine available in the United States.