Scientific Data Documentation
Information For International Travelers And Health Professionals
DETAILED DISEASE AND PREVENTION INFORMATION
Simultaneous Administration of Vaccines
Simultaneous administration of most inactivated vaccines has not resulted in
impaired antibody responses or increased rates of adverse reactions. Most
can safely and effectively be given simultaneously at separate sites.
However, when vaccines commonly associated with local side effects(such as
cholera, typhoid, and plague vaccines) are given simultaneously, the side
effects can be accentuated.
Whenever possible, live viruses not administered on the same day should be
given at least 30 days apart. Recent studies show that antibody response is
decreased when yellow fever and cholera are administered within three weeks
as compared to longer intervals. If under time constraints, the vaccines can
be given simultaneously or anytime within the 3 week period. When
considering vaccination under time restraints consider that the yellow fever
vaccine and documentation are required for certain countries and is strongly
recommended for those travelers to infected areas. The major benefit of the
cholera vaccine is for entry into a few countries requiring a certificate.
The safety and efficacy of hepatitis B vaccine, DPT, and OPV or of hepatitis
B and yellow fever administered simultaneously is similar to separate
administrations of the vaccines. However, in cholera and yellow fever the
antibody response can be lower if administered simultaneously or within 3
weeks.
There is little interaction between inactivated vaccines and Immune
Globulin. Therefore, IG may be simultaneously administered at different
sites with an inactivated vaccine.
However, live attenuated vaccine viruses might not successfully replicate
and the subsequent antibody response could be diminished when the vaccine is
given with IG. In general, parenterally administered live vaccines should
not be given for a least 6 weeks and preferably 3 months after IG
administration. Two exceptions should be noted. If IG administration
becomes necessary after a live vaccine has been given, interference may
occur, and thus the vaccine may have to be repeated after at least a 3 month
wait. If IG needs to be administered because of imminent exposure to
disease, live virus vaccines may be administered simultaneously with IG
recognizing that vaccine-induced immunity may be compromised. Administration
should be at different sites. Re- immunization should occur after 3 months
unless serology confirms antibody production. Note that IG does not
interfere with either OPV or yellow fever vaccines.
Disease Specific Menu
Cholera
Cholera is an acute intestinal infection caused by VIBRIO CHOLERA O-group I.
The current vaccines have shown a 50% effectiveness in reducing clinical
illness for 3-6 months after administration, with the greatest effectiveness
in the first 2 months. It is not routinely recommended for travelers, except
those traveling to any of the two countries requiring a Certificate of
Vaccination against cholera. A single dose of vaccine will meet the country
requirement and should be documented on a Certificate of Vaccination.
Alternatively, a medical waiver signed by a physician is generally accepted
by country officials.
The complete vaccination schedule includes 2 doses of vaccine spaced 1 to 4 or
more weeks apart. Dosages are age specific.
For infants 0-6 months of age; the vaccine is not recommended, and a medical
waiver must be provided for entry to countries requiring a certificate.
For children 6 months to 4 years of age; .2 ml given subcutaneously or
intramuscularly.
For children 5 to 10 years of age; .3 ml given subcutaneously or
intramuscularly.
If older than 10 years of age; .5 ml given subcutaneously or intramuscularly.
.2 ml intradermal dosage for travelers over age 5 may be substituted.
Booster dosages are the same as the age specific dosages and are spaced every
6 months.
Data indicates that simultaneous administration of cholera and yellow fever
vaccines produces a less-than-normal antibody response. A 3 week minimum
interval between cholera and yellow fever vaccines is recommended except in
those cases where both vaccines are required and time constraints exist.
Then they can be given simultaneously or any time within the three week
interval.
Reactions to the vaccine are: 1-2 days of pain, erythema, and induration at
the site of injection; fever, malaise, and headache. Serious reactions are
rare, but if experienced, re-vaccination is not advisable.
No specific information on the safety of cholera vaccine and pregnancy is
available, therefore vaccination should be avoided.
Dengue Fever
Complications
Complications of dengue occur rarely in adults.
Transmission
Dengue viruses are transmitted by mosquitoes, who are most active during the
day. These vector mosquitoes are found near human habitations and often are
present indoors.
Prevention
There is no vaccine for dengue fever, therefore the traveler should avoid
mosquito bites by remaining in well screened or air conditioned areas.
Travlers are advised to use bednets, to bring aerosol insecticides to use
indoors and to use mosquito repellents on skin and clothing.
Symptoms
The illness is a flu-like illness characterized by sudden onset, high fever,
severe headaches, joint and muscle pain, and rash. The rash appears 3-4
days after the onset of fever. Travelers should alert their physician of
any febrile illnesses occurring within one month after leaving an endemic
area.
Japanese Encephalitis
Japanese Encephalitis is a viral disease transmitted by mosquitoes.
Vaccination should be considered for travelers who plan long-term residence
in areas experiencing epidemics, such as Japan, Korea, or countries in South
East Asia, or the Indian subcontinent, especially those who will be
traveling or living in rural farming areas. The vaccine is presently not
available in the United States. Persons considered at risk should arrange to
receive the vaccine at the country of destination. The dosing schedule is
one shot per week for three weeks.
Tickborne Encephalitis
Tickborne encephalitis is a viral infection of the central nervous system.
Found mainly in Eastern Europe and the Soviet Union, infections are caused
by tick bites or by consumption of unpasteurized dairy products of cows,
sheep, or goats. An effective vaccine can be obtained from Immuno, Vienna,
Austria. The risk to travelers who do not visit or work in forested areas
or consume unpasteurized dairy products is apparently low. Insect repellent
containing N N diethymetatoluamide (deet) should be used by travelers in
areas of risk.
Hepatitis A Vaccine
Hepatitis A, a gastrointestinally transmitted virus of high prevalence in
developing countries, is prevented through use of Immune globulin (IG). For
travelers a single dose of IG is recommended if travel is less than 3
months. Dosages are weight specific: for persons under 50 pounds, .5 ml.
for person weighing 50 to 100 pounds, 1.0 ml. for persons larger than 100
pounds, 2.0 ml.
For prolonged travel or residence in developing countries weight specific
dosages are given every 5 months.
for persons less than 22 pounds, .5 ml
for persons weighing 22 to 50 pounds, 1.0 ml.
for person weighing 50 to 100 pounds, 2.5 ml.
for persons larger than 100 pounds, 5.0 ml.
For traveler requiring repeated IG prophylaxis, screening for total anti-HAV
antibodies before travel may eliminate the need for IG in those who are
immune.
IG prepared in the United States by the Cohen-Oncley procedure, the standard
procedure used in U.S. manufactured preparations, carries no risk of
transmitting HIV, hepatitis B, or Non A Non B hepatitis.
Pregnancy is not a contraindication to using IG.
Hepatitis B Vaccine
The hepatitis B virus is primarily transmitted through activities which
result in the exchange of blood or blood-derived fluids. Vaccination is
recommended for health care workers, and long-term travelers to high
Hepatitis B endemic areas.
Two hepatitis vaccines are currently available in the United States. A
vaccine produced from plasma of hepatitis B carriers has been available
since 1982. The second vaccine uses recombinant DNA technology - a
hepatitis B surface antigen is inserted into bakers yeast. The second
vaccine became available in 1987. Both give comparable immunogenicity and
efficacy when given in the recommended dosages.
The primary adult vaccination schedule consists of 3 intramuscular doses of
either 20ug of plasma-derived vaccine, or 10ug of the recombinant DNA
vaccine. The second dose should follow one month later, with the final dose
6 months after the first. Children may receive either vaccine at a 50% adult
dosage level spaced on the same schedule.
Optimal protection is reached after the third dosage. Some protection is
provided by one or two doses, therefore the vaccination process should be
initiated, even if it can not be completed before departure.
The duration of protection and the need for booster doses has not been
determined. The optimum site of injection in adults is the deltoid muscle,
vaccination in the buttocks results in a poorer antibody response.
The major side-effects with the hepatitis B vaccine have been soreness and
redness at the site of injection. Serious adverse reaction have rarely been
reported. The production process for the plasma vaccine has been shown to
inactivate all classes of viruses found in blood including HIV.
Pregnancy is not a contraindication to the use of the vaccine. Specific data
is not available on the safety of the vaccine for the developing fetus, but
because it contains only non-infectious HBsAG particles, administration of
the vaccine to pregnant women is not considered to constitute a risk to the
fetus.
Malaria
Malaria in humans is caused by one of four protozoan species
of the genus Plasmodium: P. falciparum, P. vivax, P. ovale, and
P. malariae. All are transmitted by the bite of an infected
female Anopheles mosquito. Occasionally transmission occurs by
blood transfusion or congenitally from mother to fetus. The
disease is characterized by fever and flu-like symptoms including
chills, headache, myalgias, and malaise, which may occur at
intervals. Malaria may be associated with anemia and jaundice,
and P. falciparum infections may cause kidney failure, coma, and
death. Deaths due to malaria are preventable.
Information on malaria risk in specific countries (pp.
15-60), is derived from various sources including the World
Health Organization. While this is the most accurate information
available at the time of publication, factors which can vary from
year to year, such as local weather conditions, mosquito vector
density, and prevalence of infection, can have a marked effect on
local malaria transmission patterns.
Risk of Acquiring Malaria
Malaria transmission occurs in large areas of Central and
South America, Hispaniola, sub-Saharan Africa, the Indian
Subcontinent, Southeast Asia, the Middle East, and Oceania. The
estimated risk of acquiring malaria varies markedly from area to
area. This variability is a function of the intensity of
transmission in both urban and rural areas within the various
regions, and also depends on itinerary and time and type of
travel. During 1980-1989, 1,834 cases of P. falciparum among
U.S. civilians were reported to the CDC. Of these, 1,491 (81%)
were acquired in sub-Saharan Africa, 136 (7%) were acquired in
Asia; 105 (6%), were acquired in the Caribbean and South America,
and 103 (6%), in other parts of the world. Of the 41 fatal
infections, 31 were acquired in sub-Saharan Africa.
Thus, most imported malaria among U.S. travelers was
acquired in sub-Saharan Africa, even though only an estimated
90,000 Americans travel to sub-Saharan Africa each year, versus
an estimated 900,000 American travel to malarious areas of Asia
and South America each year. This disparity in the risk of
acquiring malaria reflects the fact that travelers to Africa are
at risk in most rural and many urban areas, and moreover, tend to
spend considerable amounts of time, including evening and
nighttime hours, in rural areas where malaria risk is highest.
Travelers to Asia and South America, however, spend most of their
time in urban or resort areas where there is limited, if any,
risk of exposure, and travel to rural areas mainly during daytime
hours when there is limited risk of infection.
Estimating the risk of infection for different categories of
travelers is difficult, even if persons travel or reside
temporarily in the same general areas within a country. For
example, tourists staying in air-conditioned hotels may be at
lower risk than backpackers or adventure travelers. Similarly,
longer-term residents living in screened and air-conditioned
housing are less likely to be exposed than are missionaries or
Peace Corps volunteers.
Checklist for Travelers to Malarious Areas
The following is a checklist of key issues to be
considered in advising travelers.
Risk of malaria
Travelers should be informed about the risk of malaria
infection and the presence of drug-resistant P.
falciparum malaria in their areas of destination.
Anti-mosquito measures
Travelers should know how to protect themselves against
mosquito bites.
Chemoprophylaxis
Travelers should be:
-- Questioned about drug allergies and other
contraindications for use of drug to prevent malaria.
-- Advised which drug to use for prophylaxiss, and, if
chloroquine used, whether Fansidar should be carried for
presumptive self-treatment.
-- Advised to use prophylaxis continuously while in malaria-
endemic area and for four weeks after leaving such areas.
-- Informed that antimalaria drugs can cause side effects;
are serious, medical help should be sought promptly and
use of the drug discontinued.
-- Warned that they may acquire malaria even if they use
malaria chemoprophylaxis.
In case of illness
Travelers should be:
-- Informed that symptoms of malaria may be mild, and that
may be mild, and that they should suspect malaria if
they experience unexplained fever or other symptoms
such as persistent headaches, muscular aching and
weakness, vomiting, or diarrhea.
-- Informed that malaria may be fatal if treatment is de-
layed. Medical help should be sought promptly if
malaria is suspected, and a blood sample should be taken
and examined for malaria parasites on one or more
occasions.
-- Reminded that self-treatment should be taken only if
prompt medical advice should still be sought as soon as
possible after self-treatment.
Special categories
-- Pregnant women and young children require special
attention because they cannot use some drugs (mefloquine
and doxycycline).
-- Concurrent use of other drugs, e.g. beta-blockers, may be
a contraindication for use of mefloquine.
(Adapted from International Travel and Health, World Health
Organization, Geneva, 1991)
Drug Resistance
Resistance of P. falciparum to chloroquine has been
confirmed or is probable in all countries with P. falciparum
malaria except the Dominican Republic, Haiti, Central America
west of the Panama Canal, Egypt, and most countries in the Middle
East. In addition, resistance to both chloroquine and FansidarR*
is widespread in Thailand, Burma, and Cambodia, and the Amazon
basin area of South America, and resistance has also been
reported in sub-Saharan Africa.
*Use of names is for identification only and does not imply
endorsement by the Public Health Service or the U.S. Department
of Health and Human Services.
General Advice for Travelers to Malaria-Endemic Areas
All travelers to malarious areas of the world are advised to
use an appropriate drug regimen and personal protection measures
to prevent malaria; however, travelers should be informed that
regardless of methods employed, malaria still may be contracted.
Malaria symptoms can develop as early as 8 days after initial
exposure in a malaria-endemic area and as late several months
after departure from a malarious area, after chemoprophylaxis has
been terminated. Travelers should understand that malaria can be
treated effectively early in the course of the disease, but that
delay of appropriate therapy can have serious or even fatal
consequences. Individuals who have the symptoms of malaria
should seek prompt medical evaluation including thick and thin
malaria smears as soon as possible.
Personal Protection Measures
Because of the nocturnal feeding habits of Anopheles
mosquitoes, malaria transmission occurs primarily between dusk
and dawn. Travelers should take protective measures to reduce
contact with mosquitoes especially during these hours. Such
measures include remaining in well-screened areas, using mosquito
nets, and wearing clothes that cover most of the body.
Additionally, travelers should be advised to purchase insect
repellent before travel for use on exposed skin. The most
effective repellents contain N,N diethylmetatoluamide (DEET), an
ingredient in many commercially available insect repellents. The
actual concentration of DEET varies among repellents ranging up
to 95 percent. rarely children exposed to DEET have had toxic
encephalopathy. The possibility of adverse reactions to DEET
will be minimized if the following precautions are taken: apply
repellent sparingly only to exposed skin or clothing; avoid
applying high-concentration products to the skin; do not inhale
or ingest repellents or get them into the eyes; avoid applying
repellents to portions of children's hands that are likely to
have contact with eyes or mouth; never use repellents on wounds
or irritated skin; wash repellent-treated skin after coming
indoors; if suspected reaction to insect repellent occurs, wash
treated skin and seek medical attention.
Travelers should use a pyrethrum-containing flying-insect
spray in living and sleeping areas during evening and nighttime
hours.
Permethrin (PermanoneR) may be sprayed on clothing for
protection against mosquitoes.
(Insert Camera-Ready Copy of Malaria map)
Chemoprophylaxis
In choosing an appropriate chemoprophylactic regimen before
travel, persons should consider several factors. The travel
itinerary should be reviewed in detail and compared with the
information on areas of risk within a given country to determine
whether the traveler will actually be at risk of acquiring
malaria. It should be determined whether the traveler will be at
risk of acquiring chloroquine-resistant P. falciparum malaria.
In addition, it should be established whether the traveler has
previously experienced an allergic or other reaction to the
antimalarial drug of choice and whether medical care will be
readily accessible during travel.
Malaria chemoprophylaxis should preferably begin 1-2 weeks before
travel to malarious areas (except for doxycycline, which can
begin 1-2 days before). In addition to assuring adequate blood
levels of the drug, this allows any potential side-effects to be
evaluated and treated by the traveler's physician before
departure. Chemoprophylaxis should continue during travel in
the malarious areas and for 4 weeks after leaving the malarious
areas.
Chemoprophylactic Regimens
Regimen A: For travel to areas of risk where chloroquine-
resistant P. falciparum has NOT been reported, once-weekly use
of chloroquine alone is recommended. Chloroquine is usually well
tolerated. The few people who experience uncomfortable
side-effects may tolerate the drug better by taking it with
meals, or in divided, twice-weekly doses. As an alternative,
the related compound hydroxychloroquine may be better tolerated.
Chloroquine prophylaxis can begin 1-2 weeks before travel to
malarious areas. It should be continued weekly during travel in
malarious areas and for 4 weeks after a person leaves such areas.
(See table 11a for recommended dosages.)
Regimen B: For travel to areas of risk where chloroquine-
resistant P. falciparum exists, use of mefloquine alone is
recommended. Mefloquine prophylaxis should begin 1-2 weeks before
travel to malarious areas. It should be continued weekly during
travel in malarious areas and for 4 weeks after a person leaves
such areeas. (See Table 11a for recommended dosages.)
Note: In some foreign countries a fixed combination of
mefloquine and Fansidar is marketed under the name FansimefR.
Fansimef should not be confused with mefloquine, and it is not
recommended for prohylaxis of malaria. Alternative to Mefloquine
Travlers to areas of risk where drug-resistant P. falciparum
is endemic for whom mefloquine is contraindicated may elect to
use an alternative regimen, as follows:
Doxycycline alone taken daily is an alternative regimen for
short-term travel who are intolerant of mefloquine or for whom
the drug is contraindicated. Travelers who use doxycycline
should be cautioned about the possible side effects as described
in the section on adverse reactions. Doxycycline prophylaxis can
begin 1-2 days before to travel to malarious areas. It should be
continued daily during travel in malarious areas and for 4 weeks
after the traveler leaves such areas. (See table 11a for
recommended dosages.)
Chloroquine alone is taken weekly is recommended for
travelers who can not use mefloquine or doxycycline, especially
pregnant women and children under 15 kg.
Proguanil (PaludrineR) is not available commercially in the
United States. Limited data suggest that it may be effective in
East Africa, but not in Thailand, Papua New Guinea, and West
Africa. If travelers use proguanil, it should be taken as a
daily 200 mg. dose (adult) in combination with weekly
Chloroquine.
Self-treatment
Travelers who elect to use chloroquine (except those with
histories of sulfonamide intolerance) should be given a treatment
dose of FansidarR promptly in the event they have a febrile
illness during their travel when professional medical care is not
readily available, and they should be aware that this self-
treatment of a possible malarial infection is only a temporary
measure and that prompt medical evaluation is imperative. They
should continue their weekly chloroquine prophylaxis after
presumptive treatment with FansidarR. (See Table 11a for
recommended dosages for prophylaxis and Table 11b for presumptive
treatment with Fanidar.)
Mefloquine should not be used for self-treatment because of
the frequency of serious side effects (e.g. hallucinations,
convulsions) which has been associated with therapeutic dosages
of mefloquine.
Primaquine: Prevention of Relapses of Plasmodium vivax and
Plasmodium ovale.
P. vivax and P. ovale parasites can persist in the liver
and cause relapses for as long as 4 years after routine
chemoprophylaxis is discontinued. Travelers to malarious areas
should be alerted to this risk; and if they develop malaria
symptoms after they leave a malarious area they should report
their travel history and the possibility of malaria to a
physician as soon as possible. Primaquine decreases the risk of
relapses by acting against the liver stages of P. vivax and P.
ovale. Primaquine is administered after the traveler has left an
endemic area, usually during the last 2 weeks of the period of
prophylaxis after exposure in an endemic area has ended.
Since most malarious areas of the world (except Haiti) have
at least one species of relapsing malaria, travelers to these
areas have some risk of acquiring either P. vivax or P. ovale.
Prophylaxis with primaquinem is generally indicated only for
persons who have had prolonged exposure in malaria-endemic areas,
e.g., missionaries and Peace Corps volunteers. Although the
actual risk to traveler with less intense exposure is difficult
to define, with the exception of individuals deficient in
glucose-6-phosphate dehydrogenase (G6PD) (see discussion of
adverse reactions), most people can tolerate the standard regimen
of primaquine. (See Table 11a for recommended dosages.)
Adverse Reactions and Contraindications to Antimalarials
The frequent or serious side effects of recommended
antimalarials are discussed below. In addition, physicians
should review the prescribing information in standard
pharmaceutical reference texts and in the manufacturers' package
inserts.
Chloroquine and hydroxychloroquine rarely cause serious
adverse reactions when taken at prophylactic doses for malaria.
Minor side-effects may occur, such as gastrointestinal
disturbance, headache, dizziness, blurred vision, and pruritus
occur, but generally these effects do not require discontinuance
the drug. High doses of chloroquine, such as that used to treat
rheumatoid arthritis, has been associated with retinopathy, but
this serious side-effect has not been associated with routine
weekly malaria prophylaxis. Chloroquine and related compounds
have been reported to exacerbate psoriasis. Chloroquine may
interfere with the antibody response to human diploid cell rabies
vaccine when it is administrated intradermally.
Mefloquine has been asociated rarely with serious adverse
reactions (e.g., hallucination, convulsions) at prophylactic
dosage, but these reactions are more frequent with the higher
dosages used in treatment. Minor side effects observed with
prohylacitic doses, such as gastrointestinal disturbance and
dizziness, tend to be transient and self-limited.
Mefloquine is not recommended for use by travelers with a
know hypersensitivity to mefloquine; children < 15kg. (30 lbs.);
pregnant women; travelers using beta blockers; travelers involved
in tasks requiring fine coordination and spatial discrimination,
such as airline pilots; and travelers with a history of epilepsy
or psychiatric disorder.
All studies to date confirm that mefloquine is well
tolerated when used for prophylaxis; however, monitoring the
occurrence of severe adverse reactions is important because such
reactions are possible. Users of mefloquine prophylaxis, who
experience seriouss adverse reactions should consult their
physician, and the reactions should be reported to the Malaria
Branch, CDC, telephone (404) 488-4046.
Travelers who use doxycycline should be aware of the
possibility of photosensitivity, usually manifested as an
exaggerated sunburn reaction. The risk of such a reaction can be
minimized by avoiding prolonged, direct exposure to the sun;
using sunscreens that absorb long-wave ultraviolet (UVA)
radiation; and taking the drug in the evening. In addition,
doxycycline use is associated with an increased frequency of
monilial vaginitis. Gastrointestinal side effects (nausea or
vomiting ) may be minimized by taking the drug with a meal.
Tetracyclines are contraindicated in pregnancy and in children <
8 years of age.
The use of FansidarR is contraindicated in persons with
histories of sulfonamide intolerance and in infants under 2
months of age.
Proguanil rarely causes adverse reactions at prophylactic
dosage. Reported side effects include nausea, vomiting, mouth
ulcers, and hair loss.
Primaquine may cause severe hemolysis in G6PD deficient
individuals. Before using primaquine, G6PD deficiency should be
ruled out by appropriate laboratory testing.
Chemoprophylaxis for Children
Children of any age can contract malaria. Consequently, the
indications for prophylaxis are identical to those described for
adults. Mefloquine is not indicated for children <15 kg. (30
lbs.). Doxycycline is contraindicated in children <8 years of
age. (See recommended dosages in Table 11a.)
Chloroquine phosphate is manufactured in the United States
in tablet form only, and tastes quite bitter. Pediatric doses
should be calculated carefully according to body weight.
Pharmacists can pulverize tablets and prepare gelatin capsules
with calculated pediatric doses. Mixing the powder in food or
drink may facilitate the weekly administration of chloroquine to
children. Alternatively, chloroquine in suspension is widely
available overseas. Parents should calculate the volume to be
administered, because the concentration of chloroquine base
varies in different suspensions.
OVERDOSE OF ANTIMALARIAL DRUGS CAN BE FATAL. THE MEDICATION
SHOULD BE STORED IN CHILDPROOF CONTAINERS OUT OF THE REACH OF
CHILDREN.
Prophylaxis During Pregnancy
Malaria infection in pregnant women may be more severe than
in non-pregnant women. In addition, there may be increased risk
of adverse pregnancy outcomes including prematurity, abortion,
and stillbirth. For these reasons, and because chloroquine has
not been found to have any harmful effects on the fetus when used
in the recommended doses for malaria prophylaxis, pregnancy is
not a contraindication to malaria prophylaxis with chloroquine or
hydroxychloroquine. However, because no chemoprophylactic
regimen is completely effective in areas with
chloroquine-resistant P. falciparum, women who are pregnant or
likely to become so should avoid travel to such areas.
Mefloquine should not be used during pregnancy. Women of
childbearing potential who are taking mefloquine for malaria
prophylaxis should take reliable contraceptive precautions for
the duration of prophylaxis and for two months after the last
dose of mefloquine.
Doxycycline is generally contraindicated for malaria
prophylaxis during pregnancy. Adverse effects of tetracyclines
on the fetus include discoloration and dysplasia of the teeth and
inhibition of bone growth. In pregnancy therefore, tetracyclines
would be indicated only if required to treat life threatening
infections due to multidrug- resistant P. falciparum.
Proguanil has been widely used for several decades and no
adverse effects on pregnancy or fetus have been established
Primaquine should not be used during pregnancy because the
drug may be passed transplacentally to a G6PD-deficient fetus,
and cause hemolytic anemia in-utero. Whenever radical cure or
terminal prophylaxis with primaquine is indicated during
pregnancy, chloroquine should be given once a week until
delivery, at which time the decision to give primaquine may be
made.
Prophylaxis While Breast-feeding
Very small amounts of antimalarial drugs are secreted in the
breast milk of lactating women. The amount of drug transferred
is not thought to be harmful to nursing infant; however, more
information is needed. Because the quantity of antimalarials
transferred in breast milk is insufficient to provide adequate
protection against malaria, infants who require chemoprophylaxis
should receive the recommended dosages of antimalarials listed in
Table 11a.
Malaria Hotline
Detailed recommendations for the prevention of malaria are
available 24 hours a day by calling the CDC Malaria Hotline at
(404) 332-4555.
Meningococcal Disease
Vaccination for meningococcal disease is recommended for travelers going to
the sub-sahara Africa during the dry season. The countries of highest risk
are Mali, Niger, Chad, Sudan, Ethiopia, Bukina Faso, Benin, Nigeria, and the
northern parts of Somalia. In addition CDC currently recommends the vaccine
for all travelers to Saudi Arabia, Nepal, and the Delhi region of India.
Serogroup A is the most common cause of the epidemics. Meningococcal
vaccines are chemically defined antigens consisting of purified bacterial
capsular polysaccharide, each producing serogroup-specific immunity.
Only one formulation of vaccine is currently available in the United States
- quadrivalent A/C/Y/W-135 called Menomune is distributed through Connaught.
No vaccine is available for Serogroup B.
A one dose subcutaneous injection in the volume specified by the
manufacturer provides immunity for approximately 3 years. Vaccine response
rates vary with serogroups and so may be less than effective. Children
vaccinated before the age of 4 should be re-vaccinated after 2 to 3 years if
at high risk. Follow the manufacturer's instructions for proper dosing.
Reaction to the vaccine are infrequent and mild, consisting principally of
localized erythema that last for 1-2 days. Up to 2% of young children
develop a fever transiently after vaccination.
The safety of meningococcal vaccine and pregnancy has not been established.
It is prudent to avoid the use of the vaccine with pregnant women unless
there is substantial risk.
Plague
Vaccination against plague is not required by any country as a condition for
entry. Neither is it recommended except for those who are at particularly
high risk of exposure because of research or field exposure.
A 3 dose primary series spaced over about 8 weeks and an additional booster
dose six months later are available.
See package insert for dosing information.
The true protection provided by the vaccine is not known due to the limited
use.
Reactions
Mild pain, erythema, and induration at the injection site occur frequently.
With repeated doses, fever, headache, and malaise are common and more
severe. Sterile abscesses occur rarely, but no fatalities or disabling
complications have been reported.
Contraindications
In pregnancy only selected vaccinations of exposed persons would be
recommended.
Rabies
Requirements
Pre-exposure vaccination is not indicated for travelers to large cities or a
rabies free country.
Transmission
Rabies is almost always transmitted by bites which introduce the virus into
the wound. Although dogs are the main reservoir of the disease, all warm-
blooded animal bites should be suspect.
Prevention
Do not handle any animals! Any animal bite should receive prompt attention.
When wounds are thoroughly cleaned with large amounts of soap and water, the
risk of rabies infection is reduced. Exposed individuals should receive
prompt medical attention and advice on post-exposure preventive treatment.
Upon returning to the U.S. exposed individuals should contact their local
physician or state health department.
Schistosomiasis
Transmission
Schistosomiasis is developed after the larvae of a flat worm has penetrated
the skin. The larvae are released into the water from infected snails who
are the worms host. The larvae are capable of penetrating unbroken skin.
Two ingredients are necessary, fresh water and snails. Brackish water or
areas of poor sanitation are a contributing factor. Water treated with
chlorine or iodine is virtually safe, and salt water poses no risk.
Prevention
The traveler cannot distinguish between infested and non-infested water.
Therefore, swimming in fresh water in rural area should be avoided. Bath
water should either be heated to 50 degrees C (122 degrees F) for five min-
utes or treated with chlorine or iodine as done for drinking water.
Treatment
If exposed to suspected water, immediate and vigorous towel drying or appli-
cation of rubbing alcohol to the exposed areas will reduce the rish of
infection. Screening procedures are available for those who suspect
infection, and schistosomiasis is treatable with drugs.
Typhoid Fever
Transmission
Salmonella typhi, the organism which causes typhoid fever, is transmitted
through contaminated food and water.
Prevention
By drinking only bottled or boiled water and eating only cooked food, a
traveler lowers the risk of infection.
Currently available vaccines have been shown to protect 70- 90% of the
recipients. Therefore, even vaccinated travelers should be cautious in
selecting their food and water.
The primary series of vaccine consists of two shots, spaced at least 4 weeks
apart. A booster dose given every 3 years provides continued protection for
repeated exposure. If there is insufficient time for two doses a month
apart, an accelerated schedule of three shots a week apart may be
administered. It is recognized that the accelerated schedule is less
effective. A primary series need never be repeated.
Treatment
Symptoms of typhoid include fever, headaches, malaise, anorexia, and consti-
pation more often than diarrhea. Seek medical assistance immediately for
appropriate antibiotic treatment.
Yellow Fever
Yellow fever is a viral disease. Vaccines are available only through
approved yellow fever vaccination centers designated by state health
departments. Call your state and local health departments to find the center
closest to you.
One dose of .5 ml of vaccine may be administered to anyone over 9 months of
age. A booster of equal amount may be given every 10 years. Infants under 4
months must not be immunized.
Persons with a hypersensitivity to eggs should not be given the vaccine.
Persons able to eat eggs or egg products can receive the vaccine. Efforts
should be made to obtain a medical waiver for persons hypersensitive to the
vaccine. A physicians letter clearly stating the contraindication to the
vaccine, has been acceptable to some governments. It should be written on
letterhead stationary and bear the stamp used by a health department or
official immunization center to validate the International Certificate of
Vaccination. Also check embassies or consulates for waiver of requirements
information.
Reactions occur in less than 5% of those vaccinated for yellow fever. They
are generally mild, for example, headaches, low-grade fevers, myalgia, or
other minor symptoms.
Patients with immunosuppression, including AIDS, leukemia, lymphoma,
generalized malignancy, etc. or those patients using corticosteroids,
alkylating drugs, antimetabolites, or radiation should not receive the
vaccine.
Simultaneous Administration of yellow fever vaccine and other live virus
vaccines have not caused inhibition of the yellow fever vaccine. If live
viruses are not given concurrently, 4 weeks should be allowed to lapse
between sequential vaccinations. Simultaneous administration of cholera and
yellow fever vaccines has produced a lower-than-normal antibody response to
both vaccines. There is no data of interference between yellow fever and
typhoid, paratyphoid, typhus, plague, rabies, or Japanese encephalitis.
Pregnancy is not a contraindication to yellow fever vaccine. However,
specific information is not available concerning the adverse effects of
yellow fever vaccine and the developing fetus. If possible avoid
vaccination.
Vaccinations and Pregnancy
Live Virus Vaccines
Live attenuated-virus vaccines are not generally given to pregnant women or
to those likely to become pregnant within 3 months of receiving the vaccine.
For the MMR vaccine, pregnancy is a contraindication. Only with a
substantial risk of exposure to natural infection of the disease should
either yellow fever or OPV be given to pregnant women . If given during
pregnancy, waiting until the second or third trimester minimizes concerns
over teratogenicity. The risk of teratogenicity from live rubella vaccine is
small, with no evidence of congenital rubella syndrome in infants born to
mothers who inadvertently were vaccinated during pregnancy. For
poliomyelitis OPV is recommended over IPV when immediate protection is
needed.
MMR and OPV vaccines can safely be administered to children of pregnant
women in spite of viral shedding. To date the evidence shows no risk to the
developing fetus.
Inactivated Vaccines
There is no convincing evidence of risk to fetus from inactivated viral or
bacterial vaccines, or toxoids administered to pregnant women. These
include: hep B, rabies, cholera, typhoid, plague, meningococcal,
pneumococcal, and the adult formulation of the Td toxoid. If immunization is
considered, the risk and probability of contracting the disease should be
weighed against benefits and complication from administering the vaccine.
Unimmunized pregnant women who may deliver under non-hygienic circumstances
should receive two properly spaced doses of Td, preferably during the last
two trimesters. Incompletely immunized women should complete the three dose
series. Those immunized more than 10 years ago should receive a booster
dosage.
For IG there is no known risk to the fetus from passive immunization of
pregnant women.
Vaccinations of Children Less Than 2 Years of Age
The vaccine information in this section is presented in alphabetical order
by disease.
Cholera vaccine is of questionable benefit to travelers of any age. It is
not recommended in children less than 6 months old. Breast-feeding is
protective against cholera. For other infants careful preparation of formula
and food from safe water and foodstuffs should protect non-breast-fed
infants.
Diphtheria, tetanus, and pertussis is endemic in developing countries, and
therefore may put the infant at greater risk than in the U.S. Optimum
protection in the first year of life is achieved with three doses of DTP
administered normally. Infants traveling should have received 3 doses of
DTP, the first dose at 6-8 weeks of age, and the next two doses at 4-8 week
intervals. A forth dose, generally 6-12 months after the third dose
maintains protection. For infants at imminent risk, reducing the interval
between the third and forth doses of the primary series to six months may be
considered. One dosage by its self affords little protection, while two
doses provide some protection. Parents must note that less than the 3
recommended doses of DTP puts a child at greater risk of infection. If
traveling for extensive periods, travelers may wish to receive the remaining
doses of the vaccine at the recommended intervals while abroad.
Hepatitis B vaccine should be considered for infants and children who will
live 6 months or more in smaller cities and rural areas of developing
countries where hep B is endemic, and who will be in contact with the local
population. This is especially true when the local children have open skin
lesions such as impetigo, scabies, scratched insect bites, or when any risk
of exposure to blood from the local population occurs.
Immune globulin is recommended for infants and children traveling outside
the usual tourist routes if they will be eating food and water in settings
of questionable sanitation.
MMR vaccine should be administered to all children 15 months of age or
older. For earlier departure to areas of high risk, vaccines may be
administered as follows: Children 12-14 months of age may receive MMR before
their departure without need for re-vaccination; at ages 6-11 months a
single dose of single measles antigen vaccine (without mumps and rubella)
may be given before departure, with re-vaccination of the MMR vaccine coming
at 15 months, and if required as early as 12 months. Infant less than 6
months of age are protected by maternally derived antibodies. The risk of
serious disease from Mumps and rubella is so small that no vaccination is
required before 12 months. For Meningococcal vaccine effectiveness of the
vaccine in children is dependent upon the child's age when the vaccine is
administered. Protection against certain strains of the bacteria may not be
effective in children vaccinated between 3 months and 2 years. Vaccination
before 3 months of age has little effectiveness against the disease. The
vaccine may be safely given to infants with the understanding that it may be
less effective than in adults.
OPV is the vaccine of choice for all infants and children if there are no
contraindications to the vaccine. Inactivated poliovirus vaccine is also
available. Children traveling to endemic areas should receive at least 3
doses of OPV at intervals of at least 6-8 weeks. A forth dose may be given
if at least 6 weeks have elapsed since the third dose. If travel is to occur
before a child is 6 weeks old, a dose of OPV should be administered prior to
travel. The dose of OPV given before 6 weeks of age should not be counted
as part of the primary series. Children traveling to endemic areas should
complete the 3 dose primary series abroad with doses at 4 week intervals.
Children with only partial immunity should complete the primary series if
they remain in a high risk area.
For plague vaccine children under 1 year of age, dose 1 is .2 ml; dose 2 is
.04 ml and spaced 4 or more weeks later. A third dose of .04 ml follows the
second by 3-6 months. Give 2 booster doses of .02-.04 ml 6 months apart,
then one booster every 1-2 years. For children between 1 and 4 years of age,
dose 1 is .4 ml; dose two is .08 ml spaced 4 weeks later. A third dose of
.08 ml follows the second by 3-6 months. Give 2 booster doses of .04-.08 ml
6 months apart, then one booster every 1-2 years.
For typhoid fever breast feeding is likely to protect infants. Careful
preparation of formula and food from safe water should protect
non-breast-fed infants. Typhoid fever vaccine is recommended for children
older than 2 years of age traveling to areas where there is questionable
sanitation.
Yellow Fever vaccine should not be administered to any infant under 4 months
of age. Immunization of children 4-6 months old should be considered only
under very unusual circumstances. (Consult CDC at 303-221-6400.) It may be
administered to infants 6-9 months if traveling to areas of risk and when a
high level of protection against mosquito bites is not possible. Infants 9
months or older should be vaccinated if they are traveling to or living in
areas of South America or Africa where yellow fever infection is officially
reported.
General Vaccinations-Recommended for Adult Travelers
All adult travelers should have their polio and tetanus immunizations up to
date. Tetanus should be boosted every ten years. If the traveler completed
in the past a primary polio series of either OPV or IPV, they should receive
one additional dose of OPV or IPV before most travel. This is due to the
higher risk of exposure to "wild" polio virus found abroad. This is strongly
advised for travelers to less developed countries.
Persons who are unvaccinated or who do not know their polio vaccination
history should take 2 shots of inactivated polio virus vaccine at least a
month apart for protection prior to travel.
If less than four weeks are available before protection is needed a single
dose of OPV or IPV is recommended. There is a slightly higher rate of
vaccine induced polio in adults than in children following OPV. This is most
often associated with persons who either have no prior immunization or are
unknowingly immunodeficient.
Persons who receive less than a full primary course of OPV or IPV should
complete the required doses for the primary series regardless of the time
interval since the last dose. The vaccine should be of the type previously
received. No serious side effects for IPV have been documented, however
since IPV contains trace amounts of streptomycin and neomycin, person with a
history of anaphylactic reaction following administration of those
antibiotics should not receive IPV.
Travelers should be immune to measles. Most people born before 1957 have
natural immunity. Those born after 1957 should be immune either by
documented history of disease or history of vaccination.
Healthy travelers over 65 may benefit from the flu shot taken during the flu
season.
Food and Water
General Risks
Contaminated food and drink are the major sources of stomach or intestinal
illness while traveling. Intestinal problems due to poor sanitation are
found in far greater numbers outside the United States. The information
under food and water precautions can help prevent infection to many of these
diseases.
Water
General
In areas of poor sanitation only the following beverages may be safe to drink:
- Boiled or bottled water
- Hot beverages made with boiled water, such as coffee or tea.
- Canned or bottled carbonated beverages.
- Beer and Wine.
Ice and drinking containers should also be considered as contaminated. It is
safer to drink from a can or bottle of beverage than to drink from a
questionable container. Water on the surface of beverage container may also
be contaminated. Therefore beverage containers should be dry and the area to
contact the mouth should be wiped clean.
Where water is contaminated, the traveler should avoid brushing their teeth
with tap water.
Treatment of Water
Boiling is by far the most reliable method to make water safe to drink. From
a vigorous boil allow the water to cool to room temperature - do not add
ice. At higher altitudes allow water to boil for a few minutes or use
chemical disinfectants. Adding a pinch of salt or pouring water from one
container to another will improve the taste.
Chemical disinfection can be achieved with either iodine or chlorine, with
iodine providing greater disinfection in a wider set of circumstances. For
disinfection with iodine use either tincture of iodine or tetraglycine
hydroperiodide tablets, such as, Globaline, Potable-Aqua, and others. These
disinfectants can be found in sporting good stores and pharmacies. Read and
follow the manufacturer's instructions. If the water is cloudy then strain
it through a clean cloth, and double the number of disinfectant tablets
added. If the water is very cold, either warm it or allow increased time for
disinfectant to work.
CDC makes no recommendation as to the use of any of the portable filters on
the consumer market due to the lack of independently verified results to
their efficacy.
As a last resort, water that is uncomfortably hot to touch may be safe for
drinking and brushing teeth after it is allowed to cool to room temperature.
Food
General
To avoid illness food should be selected with care. All raw food is subject
to contamination, particularly in areas of poor sanitation. Questionable
foods are: salads, uncooked vegetables and fruit, unpasteurized milk and
milk products, raw meat, or shellfish. If you peal fruit yourself it is
generally safe. Food that has been cooked and is still hot is generally
safe.
For infants less than 6 months of age, breast feed or give powdered
commercial formula prepared with boiling water.
Some normally edible fish are not safe even when cooked. Tropical reef fish,
red snapper, amberjack, grouper, sea bass, and barracuda can become toxic at
unpredictable times. Highest risk areas include the islands of the West
Indies, Pacific and Indian Oceans.
Travelers Diarrhea
Travelers diarrhea is a syndrome characterized by a twofold or greater
increase in the frequency of unformed bowel movements. Symptoms include
cramps, nausea, bloating, fever, urgency, and malaise. Episodes begin
abruptly with increased frequency when traveling to areas of higher risk,
such as, the developing countries of Africa, the Middle East, Asia, or Latin
America. Risk of infection increases by type of eating establishment - from
lower risk in private homes, to high risk for food from street vendors.
TD is slightly more common in young adults than in older people, with no
difference between males and females. Td is usually acquired through
ingestion of fecally contaminated food and water.
TD lasts from 3 to 7 days but sometimes longer. Rarely is it life
threatening.
Prevention
There are four possible approaches to preventing TD - meticulous attention
to food and beverage preparation, immunization, use of nonantimicrobial
medication, and preventive antibiotic drugs. CDC does not recommend the use
of antibiotics or other medications as they can cause additional problems
themselves. Instead, careful selection of food and water is encouraged. If
illness occurs the use of such products as Lomotil or Immodium should be
sufficient for most travelers. It is not to be used by anyone with a high
fever or blood in their stools.
Treatment
If symptoms do not resolve after using these preparations, antimicrobial
drugs such as doxycycline, and trimethoprim/sulfamethoxazole (TMP/SMX for
short) can shorten the length of sickness. Consult your physician
prescription and dose schedules.
Oral fluids should be administered to suffers of diarrhea. Fruit juices
suitable for drinking, soft drinks preferably without caffeine, and salted
crackers are advised. Avoid dairy products, and all beverages that contain
water of questionable quality.
It is important for the traveler to consult a physician about treatment of
diarrhea in children and infants, because many of the drugs mentioned are
not recommended for them. The greatest risk for children and especially
infants is dehydration. Prevention of dehydration through administration of
soups, thin porridges, and other safe beverages is advised. If bloody
diarrhea, moderate dehydration, fever in excess of 102 F degrees, or
persistent vomiting occurs seek immediate medical help.
As with all diseases it is best to consult a physician rather than attempt
self-medication, especially for pregnant women and children. If diarrhea is
severe or does not resolve within a few days, or a fever occurs with
shaking, or if there is dehydration, travelers should seek medical help.
PUBLISHED MATERIALS
CDC is authorized to distribute at no cost the book Health Information for
International Travel as well as other related materials to physicians,
public health care workers, travel agencies, and units of the Federal
Government.
International Certificate of Vaccination may be ordered for officially
designated vaccination centers by calling the superintendent of documents at
202-783-3238. The cost is $2.00 each or $14.00 per 100. The form number is
PHS-731 #017-001-004405. The address of the Superintendent of Documents is
U.S. Government Printing Office, Washington, DC 20402. All previous editions
of this document are valid and may be used without problem.
If you do not qualify to receive our publications free, you can purchase the
pamphlet Health Information for International Travel.
You may purchase a current copy of the Health Information for International
Travel document, H.H.S. Publication number (CDC) 88-8280, from the
Superintendent of documents, U.S. Government Printing Office, Washington,
D.C. 20402, telephone number 202-783-3238. Please include a check or money
order for $4.75.
AIDS INFORMATION
Acquired Immunodeficiency Syndrome or AIDS is the severest manifestation of
the human immunodeficiency virus (HIV). The incubation period for AIDS may
be long, up to several years. Currently there is no vaccine, and no cure for
AIDS.
AIDS is found on every continent, with over 125 countries reporting, but
actual cases far exceeding reported information. With the global
distribution of HIV, risk of infection is behaviorally based rather than
geographically related. The international traveller should know about the
transmission and prevention of HIV infection, as well as the complications
of travel for persons with HIV infection.
HIV infection is preventable, as its transmission is not through casual
contact, air, food, or water routes; contact with inanimate objects; through
mosquitoes or other arthropod vectors. The use of any means of public travel
by people infected with HIV does not pose a risk of HIV infection to other
passengers. HIV is transmitted through sexual intercourse - heterosexual or
homosexual with an infected person; use of unsterilized syringes and
needles, (e.g. drug use, acupuncture, or tattooing); through blood or blood
components; and perinatally from an infected pregnant mother.
Travelers should avoid sexual encounters with any one thought to be infected
with HIV or whose HIV infection status is unknown. Avoid sexual encounters
with intravenous drug users, people with multiple sexual partners, including
prostitutes either male or female. Condoms may decrease but not eliminate
the risk of transmission.
Do not use drugs intravenously or share needles for any reason. Needles must
be sterile, preferably disposable, and prepackaged in a sealed, single unit
container. Diabetics or other people requiring frequent injections should
carry a supply of syringes and needles to last the entire stay abroad.
Unlike the US, Japan, Canada, Australia, and western European countries
where mandatory testing procedures have greatly reduced the risk of HIV
infection, blood and blood products available in less-developed countries
may not be formally tested for HIV contamination. Locally produced blood
clotting factor concentrates and blood from the native population should not
be used unless tested by appropriately-trained technicians using reliable
tests. US produced IG that follows the Food and Drug Administrations
procedures is safe from HIV.
Recently, several countries have established serological screening of
incoming passengers to detect either AIDS or HIV antibodies. Travelers
testing positive are refused entry. With one or two exceptions these tests
are only being done on travelers staying in a country greater than 3 months.
The testing requirements for individual countries can be obtained by calling
the appropriate Consulate office in Washington, D.C.
