By Dr Al
the world and explore every human environment. Air crew also may encounter
diseases in various environments that they do not encounter in their home
locale. As such, we can be come "food" for these diseases that are constantly
searching for a new homestead. However, many of these diseases can be prevented
by vaccinations and other prophylactic measures.
There is only one
required, international travel vaccination. That is yellow fever. This is
a virus transmitted by mosquitoes in tropical regions. It is limited to South
America from Panama to Peru and Brazil, and tropical Africa from south of the
Sahara Desert, all the way to southern Africa. Anyone entering or leaving these
zones may be required to have proof of a yellow fever vaccination. These
vaccinations, which must be attested to by an international certificate, are
valid for ten years. The vaccine itself is safe and highly effective. Once
vaccinated, you will probably acquire a lifelong immunity to this deadly
disease. However, international regulations require revaccination every ten
years. If you are unvaccinated, the disease has a very high risk of being fatal.
Other than vaccination, only avoiding being bitten by a mosquito, such as insect
repellents, netting, and other preventive measures, will prevent this disease.
The disease that
concerns us the most in aviation is tuberculosis. While the risk of
acquiring tuberculosis from a passenger onboard an aircraft is very remote, it
has happened on rare occasions that an infection has been transferred. I
discussed tuberculosis in a previous issue, and I would refer you to that
(reference Plane Safe). All air crew should have a skin test for
tuberculosis done annually, if their skin test is negative. A vaccine called BCG
is available, but is not generally used in the United States due to its
relatively low efficiency. It provides protection only about fifty percent of
the time, and makes the skin test results difficult to interpret.
diseases that can effect travellers in the airplane include mumps, measles,
rubella (German measles), and chicken pox. For those of us who were born
before 1957, we naturally acquired immunity to all these diseases. However, if
you were born after 1957, you may have had one of the early vaccines that did
not provide lifelong protection. You should consider being revaccinated by the
new quadrivalent vaccine. A single dose protects against all four of these viral
While most of us
have good protection against tetanus, relatively few Americans are well
protected against a bacterial disease called diphtheria. Diphtheria can
cause a fatal infection, and outbreaks are becoming more and more common in the
former countries of the Soviet Union as well as third world countries. A single
dose, combined with a tetanus vaccine and known as "Td", will provide a ten year
protection against both tetanus and diphtheria.
hope, will soon join smallpox as an extinct disease in the wild. Polio is
extinct in North and South America, as well as Europe, but retains pockets of
activity in Africa and Southern Asia. If your itinerary should every carry you
to any of these areas, a single dose of oral polio vaccine will protect you. We
do recommend that if you have never had a polio vaccination in your entire life,
that you should have the inactivated (Salk) vaccine as an injection first, and
follow this several months later by the lifelong protection conferred by the
oral polio vaccine. All adults should have at least one additional dose, even if
you had the full treatment and boosters as a child.
New vaccines are
available to protect against hepatitis A and B. Although both these
diseases effect the human liver, they are quite different in their cause.
Hepatitis A (infectious hepatitis) is a viral disease spread by faecal-contaminated
food. It is quite common to have this problem when dealing with street vendors
or fresh vegetables in much of the developing world. Two doses of the hepatitis
A vaccine, given six months or more apart, will provide highly effective
protection against this illness. Alternatively, you can avoid ever eating
contaminated foods by making sure that your food has been thoroughly cooked or
boiled and any fruits or vegetables are peeled before you eat them. In other
words, salads are out. Handling contaminated glasses and plates can only be a
source of infection if you proceed to put your fingers next in your mouth or
eyes. Remember, one of the most effective ways to prevent infection is to
wash your hands!
Hepatitis B is a
virus spread by blood and body fluids. In other words, its spread is identical
to the HIV virus. However, many more people are infected and die from hepatitis
B each year than from HIV. The difference is that there is a hepatitis B vaccine
given in three doses over six months. The vaccine is safe and very effective.
consider two other vaccines as well. Each fall, the annual influenza
vaccine becomes available. This is actually a mix against three strains of the
influenza A and B viruses, which the Centers for Disease Control and Prevention
has selected as being the candidates most likely to cause illness that year.
Influenza itself is usually not a deadly disease, but its side effects can
linger for up to two months after the infection. Within the next two years, the
injectable trivalent influenza vaccine should be replaced with a nasal spray
vaccine. However, due to the fact that the influenza virus mutates slightly or
"shifts and drifts" every few years, the vaccine changes almost annually and
protection from last year’s vaccine may not protect you against next year’s
viruses. So, you must repeat this vaccination annually.
recommended vaccine is the pneumonia vaccine. This single dose, lifetime
vaccination, will protect you against twenty-three strains of the pneumococcus
pneumonia bacteria. It is recommended for any smoker over age 50, and all
individuals over age 65.
You may also wish
to consider the typhoid vaccines. Typhoid is a salmonella bacteria
infection acquired from eating faecal-contaminated food, so its distribution
pattern is similar to hepatitis A; however, typhoid is much rarer. There have
been no major outbreaks in the United States in several years. There are two
vaccines currently available. One is a single injection which provides excellent
protection. Even better is the four oral capsules, which must be taken over a
period of seven days. Both are safe and effective.
There are two
other vaccines which I do not currently recommend. One is plague
and the other cholera. Plague, of course, is the extremely dangerous
bacterial disease spread by fleas or occasionally by air. This disease is quite
rare, and in fact is only endemic to Viet Nam, but more importantly the vaccine
is very painful and not very effective. Its efficacy is considered to be less
than thirty percent, and it lasts for less than six months. Likewise, the
cholera vaccine is also an inefficient vaccine. Its limited ability to protect
is lost within a few months.