Getting Ready: Pre-travel Inoculation: Recommended
Typhoid is a bacterial infection caused by the organism Salmonella typhi. It is transmitted via infected food or water. After an incubation period of from 7 to 21 days, one experiences headaches, fever, abdominal pain and cough. More serious complications include bleeding from the bowel, perforation of the bowel, or neurological involvement. It is usually treatable with antibiotics such as Cipro, but it is often resistant to other available antibiotics.
There are two vaccines available to help lessen the risk of typhoid fever. However, they are both only about 70% effective. Therefore, the most important measure is to take care with your food and water.
Typhim Vi and Typherix are injectable vaccines, which after one dose, provides good protection (60-70%) for about 3 years. The side effects are usually minor, and include some soreness at the injection site. The vaccine is safe in pregnancy, and can be administered down to the age of two. It is probably safe to give the vaccine to children younger than 2, who will be at significant risk.
Vivotif is an oral vaccine, which provides protection for up to seven years. It consists of four capsules which must be taken on alternate days. It may cause some stomach upset. Being a "live" vaccine, it should not be given to pregnant women or anyone who is immunosuppressed. Due to the dosing schedule and the need to keep the capsules refrigerated, the compliance with this vaccine is often less than perfect. A newer liquid formulation is now available so this vaccine may be used down to the age of two.
Hepatitis A is a viral infection of the liver which is transmitted through infected food and water, or from person to person. A few weeks after becoming infected, one may become ill with fever, nausea, weakness and fatigue. This is followed by jaundice (a yellowing of the skin and eyes). There is no specific treatment for hepatitis A. Thankfully, it usually is a self-limited infection, but you can count on being under the weather for at least a month. The disease is usually quite mild, or undetectable in small children. In those over 50, however, the mortality rate may approach 3% … not an innocuous infection.
Many years ago we used to administer immune serum globulin, in the butt, to prevent hepatitis A. This has now been replaced by three excellent vaccines. HAVRIX and VAQTA and AVAXIM. All provide almost 100% protection against this virus. The three vaccines are quite comparable, consisting of an initial dose, ideally at least two weeks before departure, followed by a booster from 6 to 12 months later. Having said that, getting this vaccine on the way out to the airport will likely still protect you. The initial dose provides protection for at least a year, and the booster for at least 10 years, and likely much longer. Side effects are minimal. The three vaccines may be used interchangeably. As well, if more than 1 year elapses from the time of your first vaccination, it is not necessary to start again at the beginning.
Many doctors do not immunize small children (less than 5 years of age) because the disease is so mild at this age. But there is still the chance that these toddlers may become ill, and furthermore, they may pass the virus on to other kids and non-immune adults upon their return. It is worthwhile checking the immune status of those who were born in endemic countries, as they will often have been exposed as children and will have immunity, and thus, not require the vaccine.
VIVAXIM / HEPATYRIX is a combination of typhoid and hepatitis A vaccines. It is a convenient product for those in need of both vaccines.
This is a viral infection of the liver, which is transmitted through blood, blood products and unprotected sex. It differs from hepatitis A in its mode of transmission, but more importantly, in its ability to cause more severe acute, or chronic liver disease. While most of those who are infected recover and develop immunity, about 5% go on to become "carriers" of the virus. This carriage state may lead to conditions such as chronic hepatitis, cirrhosis or cancer of the liver.
In North America, less than 3% of the general population are carriers of the hepatitis B virus. This figure may be as high as 15% in other parts of the world, particularly Africa and Asia. Therefore, the traveller to these destinations is at higher risk.
Vaccination should be recommended for the following travellers:
- longer term travellers (more than 6 months) to areas of the world with a high prevalence of hepatitis B in the local population (the figure of 6 months is a bit arbitrary, and it would not be unreasonable to offer it to shorter term travellers)
- anyone who will be at higher risk based upon occupational exposure or other dangerous behaviours - e.g. health care workers, those who plan to engage in unsafe sex
- anyone who is concerned that they might accidentally be exposed to unsafe blood or blood products or other bodily fluids while away
TWINRIX vaccine combines both the Hepatitis A (HAVRIX) and Hepatitis B (ENGERIX) vaccines. It is appropriate for those travellers who warrant or want both vaccines. It is administered as three doses, at 0 - 1 - 6 months. Side effects are minimal. For the patient, it results in fewer injections and a lower cost.
For those in a bit of a hurry, the course of TWINRIX (or hepatitis B alone) may be accelerated to 0 - 1 - 2 months, with an extra booster at 12 months, and even to 0 - 7 - 21 days, again with a 12 month booster. Both vaccines may travel unrefrigerated for up to 2 weeks, which may be of help to those wishing to carry a final dose with them. The two vaccines may be used interchangeably.
I see lots of doctors giving lots of kids TWINRIX. Many of these children and teenagers and young adults have already received hepatitis B vaccine in school. Giving them TWINRIX, when they are already protected against hepatitis B is a waste.
Cholera is a bacterial infection of the small intestine which causes severe watery diarrhea, and sometimes results in death. It is passed through infected food and water. This infection is exceedingly rare in travellers, particularly in those who stay on the beaten path and use even a small bit of common sense with their choice of water. Outbreaks of cholera continue to occur in more than 60 countries worldwide, with more than 1 million cases and 120,000 deaths each year. Countries reporting cases of cholera are regularly listed by CDC in its Blue Sheet.
The vaccine, Dukoral, is a newly available, pleasant tasting oral vaccine which has in fact been in use against cholera for more than a decade. It provides the traveller with about 50% protection against diarrhea caused by ETEC. It consists of two doses, given at least one week (no more than 6 weeks) apart. Its protection lasts only about three months, but that is longer than most people’s trips. For subsequent travels, only a booster dose is needed. The two doses must be completed at least one week prior to travel to enjoy the full protection. It may be given to children as young as two years of age.
While this vaccine is a good one, it is probably rarely indicated in travellers for prevention of cholera. Perhaps a health worker going to work in a refugee camp where cholera has broken out, or someone returning to their village back home where there may be no access to clean water would deserve the vaccine. Most travellers do have access to clean food and water and should be instructed on ways to minimize their risk, namely, "Boil it, bottle it, peel it, cook it … or forget it!"
Meningococcal disease is caused by a bacteria, which is transmitted from person to person via close contact such as coughing, sneezing or direct contact. It may involve the blood (meningococcemia) or the brain and spinal cord (meningitis). The symptoms may include fever and headache. While it often begins like a mild illness, it may quickly progress to shock or coma. It is usually accompanied by a petechial (like bruises) rash.
The vaccine, which protects against 4 strains of the bacteria – A,C,Y, W-135 - is recommended for travellers to areas where meningococcal disease is prevalent, or where there have been significant outbreaks in the recent past. This applies particularly to longer term travellers who will have close contact with the local population. The “Meningitis Belt” of Africa presents the greatest risk, particularly during the dry, winter months between December and May. As well, because there have been large outbreaks in the past, vaccination is a requirement for religious pilgrims entering Saudi Arabia.
The vaccine consists of one dose, and the side effects are minimal. It provides protection for between 3 - 5 years.
JE is a viral infection of the brain which occurs in rural parts of Asia and Southeast Asia. It is transmitted by day biting mosquitoes, particularly in areas with rice paddies and pig farming. The infection is somewhat seasonal, usually being more prevalent during the summer months of May through October. JE is thankfully quite rare in travellers, with most infections being asymptomatic. However, it can cause death in 20% of clinical cases, and disability in up to 50%. The very young and the very old are at greatest risk. In most of my experience, these are not the ones going off to rural areas of transmission.
Japanese encephalitis vaccine is recommended for those who plan prolonged exposure in the endemic areas during the transmission season. The newly available vaccine, IXIARO, consists of two doses a month apart. Side effects are less than with the previously available vaccine (JE-VAX) and the concern about delayed allergic reactions is gone. Some of those travellers who are at risk might opt to get the vaccine locally for a lot less money.
Rabies is a viral infection of the central nervous system, which when contracted by humans is thought to be 100% fatal in the absence of proper pre- or post exposure vaccination. It is transmitted by the bite, scratch or rarely a lick from infected animals, most commonly dogs. Cats, bats and monkeys may also be infectious. In many countries of the world, stray dogs, many of whom may have rabies, are a tremendous problem. Not all dogs behave like Old Yeller (if you remember the Disney movie from the 1950s). Rather, they may be docile, and rather pathetic looking …. just the kind of animal you’d love to pet! Don’t!
Pre-exposure vaccination, which consists of 3 injections over 30 days (days 0 - 7 – 21 or 30), is only recommended for those at the highest risk. This may include those with occupational exposure (veterinarians, spelunkers), or others who by nature of the location and duration of their travels might be exposed. Children, who are reputed not to have the same common sense as adults, may be at greater risk. Considering that a bite in a child is likely to be closer to the head than in an adult, small kids are a greater risk. Pre-exposure vaccination does not preclude the need for further injections after a potentially rabid bite.
Rabies vaccine, not unlike several of the other vaccines, is quite expensive. It has been found that by using 0.1 cc (1/10 of the usual dose) intradermally, as opposed to 1.0 cc intramuscularly, that the same level of immunity can be achieved. This can result in a tremendous dollar saving (like enough to live for a week in Ghana), assuming that you can find other family members or friends with whom to share the vial of vaccine.
There’s no point looking up the symptoms of rabies, because of you have them, you will almost certainly die. But the commonest question I hear is “If I get bitten, how long do I have to start the rabies vaccine?” The rabies virus travels along the nerve to the brain, and this may be a slow process. The closer it is to your brain, the more urgent the situation. But my answer to that question would be “You always have time to get to a big city for the vaccine, or even home if necessary.”
If such a bite occurs, it is imperative that the bite be thoroughly cleansed with soap and water. If one has received pre-exposure vaccination, then there is still a need for 2 further injections (on days 0 and 3) of vaccine after exposure. For the person who has not previously been vaccinated, it is necessary to receive HRIG (Human Rabies Immune Globulin) as quickly as possible. This provides some immediate protection. As well, immunization with the rabies vaccine on days 0,3,7,14 and 28 should be started.
Let me repeat that… if you get bitten...
- wash the wound
- go for good medical care and rabies vaccine
- call home just to ensure you are getting the correct treatment
Human rabies immune globulin (HRIG) is sometimes exceedingly expensive, and / or difficult to find in some of the more remote parts of the world. It is not exactly cheap back home either! As I said, I always ask my volunteers to call me if they are bitten, just to ensure that they are receiving the correct treatment.
This viral infection of the brain is found in rural areas of both Eastern and Western Europe. As the name implies, it is transmitted via ticks, which like to jump off the plants and bushes onto unsuspecting, and uncovered hikers. Ticks do their feeding from spring through fall, so only those who travel into rural areas during this period are at risk.
The vaccine (FSME Immune) consists of two doses, given 1 - 3 months apart. Booster doses should be administered at 18 months for prolonged protection. Personal measures such as wearing long pants and socks, using insect repellents, and inspecting one’s skin at the end of the day for embedded ticks should be encouraged.
See section on Tick-borne Diseases.
TB is a bacterial infection which primarily affects the lungs, though it may affect other organs such as the kidney, the bowel and the lymph nodes.
Unfortunately, it is on the increase throughout the world, as are drug-resistant strains of the bacteria. Many people, especially in less developed countries, have been exposed to TB in the past, and have developed some immunity to the infection. However this so-called immunity may break down, sometimes because of other medications or medical problems, and the infection may "reactivate".
Infection with TB is a fairly small risk to most travellers, but it does occur. Those who are at the greatest risk are travellers going off to highly endemic areas for longer periods of time, and who will have lots of exposure to the local population. Long term volunteers and missionaries fit this description.
There is a fair bit of controversy regarding immunization to prevent TB. Most of the world outside of North America routinely administers BCG to children at birth. This is supposed to prevent TB. In fact, from the studies that have been done, it is not absolutely certain whether BCG works best in certain age groups, against certain forms of TB, and in certain geographic areas.
The Canadian approach has always been to do a TB skin test (Mantoux test) prior to travel. This test is usually normal or negative, unless there has been past exposure or vaccination with BCG. Being negative, the usual plan is to repeat the test a few months after return. In this way, we detect those who have "converted" from negative to positive. It is this group who is at higher risk of developing active TB, and hence would be offered some form of medication, usually INH, as chemoprophylaxis for 6 months.
Considering the spread of multi-drug resistant TB and the difficulty in doing yearly skin tests, it might be worthwhile to at least discuss the pros and cons of BCG with high risk travellers, particularly young children.
This unfortunate illness is the most common malady amongst travellers, affecting up to 50% of those who spend two weeks or more in the tropics. "Boil it, bottle it, peel it, cook it, wash your hands . or forget it" is the still the best advice. Dukoral is an oral vaccine which provides moderate protection for three months against Enterotoxigenic E. coli, the most common cause of TD. It consists of two doses, taken a week apart. It tastes good and is virtually free of side effects. Consider it if you would like to give yourself some added protection against TD.