++
The primary reason children are seen in travel clinics or at
a pediatrician’s office specifically for travel evaluation
is to receive required or highly recommended vaccines not typically needed
in the United States. While many parents request the visit specifically
for this reason, they are not aware of the other travel-related health
issues that may affect their child. The travel visit is a good chance
to educate parents on infectious and noninfectious travel health
issues for their child. Travel immunizations can be expensive and
are often not covered by insurance plans. Parents should be made
aware of the costs of immunizations and the frequent lack of insurance
coverage for these immunizations.
++
Incomplete immunization is not uncommon in children from the
United States traveling to other countries. It is important to emphasize
to parents, particularly parents who are opposed to all vaccination,
that their child’s risk of many vaccine-preventable diseases
is significantly higher in many countries outside the United States,
particularly developing countries, than it is in the United States.
Children should be fully immunized with all routine childhood vaccines prior
to travel. Complete information on routine immunizations, including
schedule, adverse effects, contraindications, and special indications,
is summarized in Chapter 245, “Immunizations.” This
chapter focuses on details about routine immunization germane to children
traveling internationally. An accelerated vaccination schedule is
available for children who have missed 1 or more immunizations (eTable 18.1). Complete information on childhood
and adolescent immunizations is available on the CDC Web site (http://www.cdc.gov/vaccines/recs/schedules).
The following discussion is focused on details about routine immunization
germane to traveling internationally.
++
+++
Diphtheria, Tetanus, and Pertussis
++
Diphtheria, tetanus, and pertussis are all present in developing
countries, and tetanus and pertussis remain significant risks to
the unvaccinated in the United States. Pertussis has increased in frequency
in the United States, and the availability of vaccines with only
pertussis and tetanus components has resulted in the recent recommendation
that adolescents receive booster immunization with the tetanus-acellular
pertussis (TdaP) vaccine at age 11 to 12 years rather than a tetanus
and diphtheria toxoids booster (eTable 18.1).
A travel clinic visit is also a chance to give the tetanus-acellular pertussis
vaccination to older adolescents if they did not receive it or a
tetanus and diphtheria vaccine at age 11 to 12 years.
+++
Haemophilis influenzae Type B
++
H. influenzae remains the most common cause
of meningitis in children 6 months to 3 years of age in many developing
countries in which the vaccine is not available. Children under
the age of 5 years and children with medical conditions that increase
their risk of H. influenzae infection should be
vaccinated against it.
++
Hepatitis A is a major health risk in many countries. Hepatitis
A is transmitted by infected food or water. It can be asymptomatic
in young children, who pass it on to older children and adults.
Hepatitis A immunization is now required by many states. Children
under 1 year of age and those older than 1 year who are traveling
to a hepatitis A–endemic area less than 4 weeks after the
first hepatitis A vaccine dose should receive intramuscular immunoglobulin.
For short-term protection (1–2 mo), 0.02 mL/kg
of immunoglobulin is given intramuscularly; for long-term protection
(3–5 months), 0.06 mL/kg is given intramuscularly
and repeated every 5 months while exposure to hepatitis A continues.
Immunoglobulin can be administered at the same time as the inactivated
vaccine but should be given at a separate site and in a separate
syringe. If a child requires measles, mumps, and rubella (MMR) or
varicella immunization, these live-attenuated viral vaccines should
be given either 2 weeks (MMR) or 3 weeks (varicella) before or 3
months (MMR) or 5 months (varicella) after immunoglobulin administration.
++
Hepatitis B is common in many parts of the world, with particularly
high rates in countries in southeast Asia and sub-Saharan Africa.
Exposures that increase risk of hepatitis B infection include sexual
activity, blood transfusion, use of unsterilized needles, and close
contact with infected children with exposed skin lesions. Since
vaccination with 2 doses may provide a degree of protection, vaccination
should be initiated prior to travel even if the full course of immunization
cannot be completed.
++
Human papillomavirus is associated with cervical carcinoma in women,
and the vaccine is now recommended for all females as a 3-dose series
starting at age 11 years. It can be started as young as age 9 years
(eTable 18.1).
++
In tropical areas, influenza can occur throughout the year. In
the temperate regions of the Southern hemisphere, including Australia
and South America, most activity occurs from April through September.
In the Northern hemisphere, including the United States and Canada,
influenza generally occurs from November through March. Yearly influenza
vaccination is recommended for children 6 to 59 months old. The
inactivated vaccine may be used in children 6 months or older and the
live attenuated vaccine in children 2 years and older (eTable
18.1). Children 6 months and older are at increased risk for
complications of influenza, as are children of any age with chronic
medical conditions such as cardiac, renal, or pulmonary disease;
immunosuppressive conditions or therapy; human immunodeficiency
virus (HIV) infection; sickle cell disease; and diabetes mellitus;
these children should receive only the inactivated vaccine. At present,
there is no vaccine effective against avian influenza.
+++
Measles, Mumps,
and Rubella
++
Measles is common in many developing countries and in some industrialized
nations. Mumps and rubella are also seen in developing countries, and
outbreaks of mumps have occurred in the past decade in the United
States. All children should be immunized with the MMR vaccine at
12 to 15 months old and at 4 to 6 years old unless there is a contraindication.
In children traveling internationally, the second vaccination can
be given as soon as 4 weeks after the first (Table
18-1). In the accelerated schedule, the first MMR vaccination
can be given to children as early as 6 months of age, but if the vaccine
is given at earlier than 12 months, the child should be considered
unvaccinated and given 2 additional doses at least 4 weeks apart after
12 months of age. Immunization with MMR is not performed in children
younger than 6 months because of poor immunogenicity of the vaccine
in this age group and because these children are considered to be protected
by maternal antibodies. HIV-infected children who travel abroad
should be vaccinated unless severely immunocompromised (see Chapter 188), because measles can cause very severe disease in an HIV-infected
child.
++
++
Neisseria meningitidis causes epidemic and endemic
disease worldwide (see Chapter 275). Vaccination against the meningococcus
is now recommended for all children in the United States at age
11 to 12 years or at age 13 to 18 years if not immunized earlier.
Vaccination with the quadrivalent protein-conjugate A/C/Y/W-135
vaccine (MCV-4) is recommended, but vaccination with the quadrivalent
polysaccharide A/C/Y/W-135 vaccine is
an acceptable alternative. Both vaccines are licensed for use in children
2 years and older, and since young children who travel to certain
developing countries are at higher risk of meningococcal disease,
this immunization is also covered in this chapter under “Travel Vaccines.”
++
Streptococcus pneumoniae is among the most common
causes of bacterial pneumonia, bacteremia, and bacterial meningitis
in children in developing and industrialized nations. Children under
2 years old should receive routine immunization with the protein-conjugated
7-valent pneumococcal vaccine (PCV-7), using the catch-up schedule
if needed, and the Advisory Committee on Immunization Practices
recommends that vaccination with PCV-7 be considered in all unimmunized children
24 to 59 months old (see eTable 18.1). Children
over 2 with a high risk of pneumococcal disease, such as children
with sickle cell disease, asplenia, HIV infection, congenital immunodeficiency,
nephrotic syndrome, chronic cardiac, or pulmonary disease, and children
treated with immunosuppressive medications, should be immunized
with PCV-7 if they are unimmunized. The Advisory Committee on Immunization
Practices recommends that these children receive a dose of the 23-valent
polysaccharide vaccine at least 2 months after they complete PCV-7
vaccination.
++
Poliomyelitis was eradicated from the Western hemisphere in 1991,
but it remains endemic in several developing countries. An epidemic
in Nigeria in 2004 underscored the importance of vaccination for prevention
of poliomyelitis.6 Unvaccinated adults who are
at increased risk of exposure to poliovirus and who cannot complete
the recommended inactivate poliovirus vaccine (IPV) regimen (0,
1–2, and 6–12 months) should receive 3 doses of
IPV given at least 4 weeks apart. Length of immunity conferred by IPV
immunization is not known; a single booster dose of IPV is recommended
for fully vaccinated adults traveling to endemic areas.
++
Rotavirus is the leading cause of diarrhea in children worldwide,
most often affecting children under the age of 2 years. Children
under 32 weeks old should receive rotavirus immunization. The first
dose should not be given after 12 weeks of age, and the last dose
should be given before 32 weeks of age (eTable
18.1).
++
All children 12 months or older who have no history of varicella
vaccination or chickenpox should be vaccinated unless there is a
contraindication to vaccination. Infants younger than 6 months are
generally protected by maternal antibodies. Children younger than 13
years require only 1 dose; children 13 years or older require 2
doses 4 to 8 weeks apart (eTable 18.1).
++
The dosages and age restrictions of vaccines specifically for
children traveling internationally are summarized in Table
18-1.
++
Cholera is present in many developing countries, but the risk
of infection among travelers to these countries is very low. A new oral
live cholera vaccine that is effective against most cholera strains
is available in Canada and Europe for children older than 2 years,
but no cholera vaccine is currently available in the United States.
No country or territory currently requires cholera vaccination.
+++
Japanese Encephalitis
++
Japanese encephalitis is transmitted by night-biting mosquitoes
in rural areas of Asia, where people are in close proximity to livestock.
The vast majority of infections are asymptomatic, but when symptomatic,
the disease can have up to a 30% case fatality rate. The
risk in travelers is less than 1 case per million travelers, but
the risk is highest in children.7 Disease generally
occurs from June to September in temperate zones and throughout
the entire year in tropical zones. Parents of very young children
should be discouraged from traveling with their children to high-risk
areas. Vaccination is recommended for travelers planning visits
of greater than 1 month to rural areas of Asia where the disease is
endemic, especially areas of rice or pig farming, or shorter visits
to these areas if the traveler will be camping, hiking, or frequently
engaged in other outdoor activity or work. Precautions to avoid
mosquito bites reduce the risk of infection.
++
The inactivated Japanese encephalitis vaccine has a high efficacy
(> 95%), but local reactions occur in up to 20% of
vaccine recipients, mild systemic reactions (headache, myalgias, and
rash) in 10%, and hypersensitivity reactions including
urticaria and angioedema in up to 0.6% of vaccine recipients.
Hypersensitivity reactions may occur within minutes but may delay
as long as 2 weeks after vaccination. The vaccination series, given
on day 0, 7, and 30 (Table 18-1), should
be completed at least 10 days before travel so that any adverse
reactions to the vaccine can be observed and treated. A booster
dose is given at 24 months if exposure risk remains high. The vaccine
may be used in children over 1 year of age (Table
18-1).
++
Neisseria meningitidis causes epidemic and endemic
disease worldwide. Most cases occur in the “meningitis
belt” of sub-Saharan Africa between December and June.
Epidemics have also occurred in the Indian subcontinent and Saudi
Arabia among pilgrims to the Haj. Saudi Arabia requires all pilgrims
to Mecca to have documentation of meningococcal vaccination 10 or
more days but less than 3 years before arrival. Cases of meningococcal
disease in American travelers to other areas are rare. Vaccination
is indicated primarily in travelers to an area with an active outbreak
or those who may have prolonged contact with the local population
in an endemic area, especially in crowded conditions. Serogroup
A is the most common cause of epidemics outside the United States,
but serogroup C and, rarely, serogroup B have also been associated
with epidemics.
++
There are 2 meningococcal vaccines available in the United States:
a quadrivalent polysaccharide A/C/Y/W-135
vaccine (MPSV-4) and a quadrivalent protein-conjugate A/C/Y/W-135
vaccine (MCV-4) (Table 18-1). The quadrivalent
protein-conjugate vaccine (MCV-4) is the preferred vaccination for
all children over 2 years of age who require immunization. For children
under 2 years of age, there are currently no licensed indications for
either vaccine. For children 3 months of age and older, MSPV-4 has
been used in children who are at risk of serogroup A infection, as
the vaccine induces an antibody response to this serogroup (but
not others) in children as young as 3 months. A small study recently showed
that MCV-4 was safe and partially immunogenic in infants age 2 months
and older, but there is no US Food and Drug Administration approval
for this vaccine in children under 2 years old.8 Children
vaccinated before 4 years of age should be revaccinated after 2
to 3 years if they received MPSV-4 or MCV-4 and remain in an endemic
area. For children 4 years or older, repeat vaccination should be considered
5 years after initial vaccination if they remain at high risk, particularly
if they received MPSV-4. A novel tetravalent CRM(197)-conjugated
meningococcal vaccine (MenACWY) was recently shown to be highly
immunogenic in infants if given at 2, 4, and 6 months.9 This
vaccine is not yet licensed in the United States.
++
Rabies is discussed in Chapter 321. Rabies
is endemic in many countries in Africa, Asia, and Central and South
America. Children, who are more likely to receive facial bites,
and hikers in remote areas are at higher risk. Preexposure rabies
prophylaxis should be considered if a child will be in an endemic
area for longer than 1 month or will be traveling to an area where
rapid, effective postexposure prophylaxis may not be available.
In a rabies-endemic area, an animal bite is a medical emergency,
and this point should be emphasized to parents and adolescents.
Immediate medical care must be sought at a facility that can administer
appropriate postexposure rabies prophylaxis. Ideally, the animal in
question should be caught and quarantined for 10 days of observation
for signs of rabies. Postexposure prophylaxis is required even for
individuals who received preexposure vaccination. This should be
made clear to those who receive preexposure prophylaxis so that
they understand that preexposure vaccine does not eliminate all risk
for the disease.
++
Three inactivated rabies vaccines are available in the United
States for preexposure vaccination: the human diploid cell (HDC) vaccine
(Imovax), the rabies vaccine absorbed (RVA), and the purified chick
embryo cell (PCEC) vaccine (RabAvert). Preexposure prophylaxis is
given either intramuscularly (HDCV, RVA, or PCEC) as 3 doses (1
mL) on days 0, 7, and 28, or intradermally (HDCV) as 3 doses (0.1
mL) on days 0, 7, and 28. Postexposure prophylaxis is given as five
doses (1 mL) of HDCV, RVA, or PCEC vaccine intramuscularly on days
0, 3, 7, 14, and 28 if previously unvaccinated and 2 doses (1 mL) intramuscularly
on days 0 and 3 if previously vaccinated. Previously unvaccinated
individuals should receive rabies immunoglobulin (RIG) (20 IU/kg,
with as much of the dose as possible infiltrated around the wound
site) at the time of initial postexposure prophylaxis. Previously
vaccinated individuals should not receive RIG. Children receiving
mefloquine or chloroquine should be vaccinated intramuscularly because
immune response to intradermal vaccine may be suboptimal in these children.
In some countries, rabies vaccines are still derived from neural
tissue and carry an increased risk of adverse reactions, often with
neurologic sequelae. Unpurified or purified equine RIG preparations
are still used in some developing countries and are also associated
with a higher risk of severe reactions, including serum sickness
and anaphylaxis. If rabies prophylaxis is started abroad, neutralizing
titers should be checked on return and immunization completed with
a cell culture–derived vaccine.
++
Salmonella typhi infection (typhoid fever) is
discussed in Chapter 283. It is common in
many developing ountries in Asia, Africa, and Latin America. Typhoid
vaccination is recommended for children traveling to the Indian
subcontinent, the area of highest risk, and for individuals traveling
to endemic areas who are at higher risk of infection, particularly
children visiting developing countries, as well as long-term travelers
(those traveling for more than 4 weeks) and backpackers. Vaccination
should be strongly considered for all children over 2 years old
who are traveling to endemic areas.
++
Two typhoid vaccines, the intramuscular Vi-polysaccharide vaccine
(ViCPS) and oral Ty21a strain live-attenuated vaccine (Ty21a), are
available for use in children in the United States. The intramuscular
ViCPS vaccine is licensed for use in children 2 years and older.
It can be given any time before departure but, ideally, at least
1 month before travel. The oral Ty21a vaccine can only be used in
children 6 years and older. The oral vaccine is given in 4 doses
over a 1-week period: 1 enteric-coated capsule is swallowed whole
with a cool drink, at least 1 hour before a meal, every other day until
the 4 doses are completed. Antibiotics inhibit the immune response
to the oral Ty21a vaccine; the vaccine should not be given within
24 hours of antibiotic treatment. Mefloquine, chloroquine, and atovaquone-proguanil can
be given concurrently with the oral Ty21a vaccine without affecting
the immune response to the vaccine. Immunocompromised children should
receive the intramuscular ViCPS vaccine. An advantage of the oral Ty21a
vaccine is that reimmunization for children at risk is required
only every 5 years, as compared to every 2 years for the intramuscular
ViCPS vaccine. The intramuscular and oral vaccines are similar in
price.
++
Yellow fever is a mosquito-borne viral hemorrhagic illness, sometimes accompanied
by severe hepatitis and liver failure leading to jaundice, hence
the name “yellow fever.” It is further discussed
in Chapter 307. Yellow fever is present in tropical areas of
South America and Africa.
++
Some countries require proof of yellow fever vaccination from
all entering travelers. Current requirements can be obtained on
the CDC Web site (http://www.cdc.gov).
Most countries accept a medical waiver for children who are too
young to be vaccinated (less than 4 months old) and for individuals
with a contraindication to vaccination, such as immunodeficiency.
Children with asymptomatic HIV infection may be vaccinated if exposure
to yellow fever virus cannot be avoided.
++
Vaccination against yellow fever is indicated in children older
than 9 months. Yellow fever vaccine (0.5 mL SC), a live-attenuated vaccine
(17D strain) developed in chick embryos, is safe and highly effective
in children older than 9 months, but in younger infants, it is associated
with an increased risk of encephalitis (0.4%) and other
severe reactions. Encephalitis occurs most frequently in children under
4 months old: 14 of 18 reported cases of vaccine-associated encephalitis
were in children 4 months of age and younger. Yellow fever vaccine
is also associated with increased systemic adverse events in adults
over age 65. Yellow fever vaccine should never be administered to
infants younger than 6 months of age; infants 6 to 8 months old
should be vaccinated only if they cannot avoid traveling to areas
with an ongoing yellow fever epidemic and where a high level of
protection against mosquito bites is not possible. Children with
a history of anaphylactic reactions to eggs should not receive yellow
fever vaccine, although desensitization therapy can be done if the
vaccine is absolutely necessary. Very long-lived immunity develops
to this vaccine, but international travel certificates require proof
of immunization within 10 years.
++
Traveler’s diarrhea is the most common travel-related
illness in children and adults.10 Traveler’s
diarrhea is acquired through contaminated food or water. Numerous
bacterial, viral, and protozoal pathogens are associated with traveler’s
diarrhea. Enterotoxigenic Escherichia coli is still
the most common cause. Other bacterial causes include Shigella,
Salmonella, Campylobacter, Vibrio cholerae, Vibrio parahaemolyticus,
Aeromonas hydrophilia, and Plesiomonas shigelloides.
The most common protozoal cause of traveler’s diarrhea
is Giardia lamblia. Giardiasis may also present
with bloating, stomach cramps, or abdominal pain. Other protozoal
causes such as Entamoeba histolytica, Cryptosporidium parvum, and Isospora are
more common in long-term travelers. Rotavirus and other viral pathogens
may also cause traveler’s diarrhea. High-risk areas for
traveler’s diarrhea (attack rates of 25–50%)
include developing countries of Latin America, Africa, the Middle East,
and Asia. Intermediate risk occurs in the Mediterranean, China,
and Israel. Low-risk areas include North America, Northern Europe, Australia,
and New Zealand. Drinking only safe water and attention to proper
preparation of food can reduce the risk of developing traveler’s
diarrhea (see “Water” and “Food” in this
chapter). Chemoprophylaxis for traveler’s diarrhea is not
recommended for children.
++
Dehydration is the primary risk in children with traveler’s
diarrhea. Parents should be aware of the availability of oral rehydration
solution packets in most developing countries and of the importance
of using bottled or boiled water with the solution to prevent or
treat dehydration. Bismuth subsalicylate given every 4 hours (16.7 mg/kg/dose,
or 100 mg/kg/day), decreases the rate of stooling
and shortens the duration of illness.11 Higher
doses should be avoided to avoid salicylate toxicity, and bismuth
subsalicylate should not be given to a child who has or might have
influenza, because salicylates may increase the risk of Reye syndrome
in children with influenza. Antimotility agents such as diphenoxylate (Lomotil)
and loperamide (Imodium) should be avoided in children under 8 years.
In children over 8, loperamide (2 mg orally, up to 3 times a day)
may be useful in decreasing stool frequency if the child does not
have a high fever or bloody stools.
++
Presumptive treatment of traveler’s diarrhea is recommended
in children and adults, though there is little pediatric data on
the efficacy of this treatment. The drug of choice for children
is azithromycin (10 mg/kg/day, maximum dose of
500 mg, for 3 days). Ciprofloxacin (25–30 mg/kg/day,
divided into 2 doses, maximum dose of 500 mg twice a day, for 3 days)
is an acceptable alternative.12 Azithromycin is
not specifically approved for the treatment of diarrhea, but it
is highly effective against most pathogens that cause traveler’s diarrhea
and can be prescribed in powder form that can be made into a liquid
suspension when needed. Ciprofloxacin is not approved for use in
children but has been used extensively and shown to be safe in children.13 Prescriptions
for one or the other medication should be given to parents to fill
and take with them when they travel with their children or given
to the child if the child is an adolescent traveling alone or with
a group. Infants and young children who have significant diarrhea
should seek medical attention, particularly if stools are bloody
or the child has a high fever (over 102 °F), chills
or moderate to severe dehydration.