Typhoid
What
is typhoid, how is it spread, and how is it treated?
Typhoid fever is caused by bacteria ( Salmonella
typhi ) and usually manifests with a combination of fever,
chills, headache, weakness, loss of appetite, abdominal pain, body
aches, and cough. Small, red spots appear on the chest, abdomen, and
back of about 20 percent of white patients. Constipation is common in
older children and adults, but diarrhea may occur in younger
children. The germ that causes typhoid fever can stay in the
bloodstream or cause infections in the bones, liver, or lungs.
Typhoid fever can cause a life-threatening perforation of the
intestines and massive bleeding. Antibiotics are available to treat
typhoid fever. Unfortunately, the disease is becoming resistant even
to the newest and best of the antibiotics. Without treatment, about
30 percent of patients die.
Humans shed the bacteria in their stool, which then
contaminates water or food. Susceptible persons later consume the
contaminated water or food. The spread of this disease directly from
one person to another is uncommon.
Two to 5 percent of untreated typhoid fever patients
shed the bacteria in their stool for years and years and so, like
"Typhoid Mary," they become a source of infection for many
other persons. They are called chronic carriers.
Typhoid fever is common on the Indian subcontinent
and in developing countries in Latin America, Asia, and Africa.
Worldwide, an estimated 16 million cases and 600,000 deaths are
reported each year from typhoid fever. About 1.3 out of 500,000 U.S.
citizens got typhoid fever while traveling abroad in the early 1990s.
How
effective is typhoid vaccine, and who should get it?
There are three different typhoid vaccines: one is
given by mouth (Ty21a) and two are injected (the ViCPS, or
"Vi" form, and a parenteral inactivated, older form). Each
protects roughly 50 to 80 percent of recipients. The schedule depends
on the age of the recipient and on the form used. The vaccine given
by mouth requires careful adherence to a somewhat complex eight-day
regimen. The "Vi" form requires one injection initially.
The other injected form initially requires two doses separated by at
least four weeks.
No country currently requires typhoid fever vaccine
for entry. However, because there is a risk of typhoid fever for U.S.
travelers, the vaccine is recommended for those who will have
prolonged exposure to potentially contaminated food and drink while
visiting the Indian subcontinent, or developing countries in Latin
America, Asia, or Africa. Vaccination is of particular value for
persons who will be visiting smaller cities, villages, and rural
areas.
Vaccination should not be used as a substitute for
careful avoidance of contaminated food and beverages.
Who
should not get the vaccine?
-
Persons with a history of a severe allergic or
systemic reaction following a prior dose of typhoid fever vaccine
or any of its components should not receive the vaccine.
-
Persons with a moderate or severe acute illness
should postpone vaccination.
-
Persons with typhoid fever or who are chronic
carriers of it should not receive the vaccine.
-
A pregnant woman should receive the typhoid fever
vaccine only if it is clearly needed.
Injected typhoid vaccines
Oral typhoid vaccine
-
Children less than 6 years old should not receive
the vaccine.
-
Persons who are immuno-compromised should not
take this vaccine.
-
Persons with fever, persistent diarrhea, or
vomiting should not receive this vaccine.
-
Persons who are on medications to kill bacteria,
viruses, or malaria should discuss this vaccine with their
healthcare provider before receiving it. Vaccination may need to
be postponed.
What
are the vaccine risks and side effects?
Injected typhoid vaccines
-
Tenderness, swelling, and redness at the typhoid
fever vaccine injection site commonly start within 6 to 24 hours
and last a day or two.
-
About half as many persons experience generalized
symptoms after the Vi form than after the older vaccine. After
the older vaccine, fever, muscle aches, and nausea each effect a
few percent of recipients and about 10 percent get a headache.
-
Severe allergic reactions and other severe
reactions occur rarely after either injected typhoid fever
vaccine.
Oral typhoid vaccine
Although side effects may occur, they usually resolve
on their own without medical care. Side effects may include hives or
problems with the digestive tract (nausea, vomiting, diarrhea,
abdominal cramps).
Additional
notes
Plague vaccine and cholera vaccine often cause side
effects much as the older injected typhoid fever vaccine does.
Theoretically, getting these vaccines at the same time could lead to
a bigger reaction. If you have time to separate these vaccinations by
a week or more and still get all the vaccines you need before travel,
you may have less discomfort.
