Dr. Laufer is assistant professor of pediatrics, division of infectious diseases and tropical pediatrics at the Center for Vaccine Development, University of Maryland School of Medicine, Baltimore. She has nothing to disclose in regard to affiliations with, or financial interests in, any organization that may have an interest in any part of this article.
Preparing children to travel with their families to a developing country requires special attention. The first part of this article (February 2006) reviewed the needs of groups with particular concerns (adolescents, children with a disability, children with a chronic disease) and discussed preparation for the journey itself, general safety concerns, and protecting children against gastrointestinal infection and insects. In this part, I review immunizations, prophylaxis against malaria, management of traveler's diarrhea, and services provided by local travel clinics.
A check on standard immunizations
A pretravel visit is an excellent opportunity to review your patient's vaccination history. Infections that have been almost completely eliminated in the US—such as measles, polio, and Haemophilus influenzae type B—continue to cause childhood illness abroad. Recently, unvaccinated Americans traveling abroad have contracted measles and diphtheria.1,2 For parents who have previously been reluctant to fully vaccinate their children, the significant risk of acquiring vaccine-preventable infection abroad makes complete vaccination before travel imperative.
Young children who have not completed the primary vaccine series should be immunized according to the accelerated vaccination schedule to maximize protection before they travel. In general, this means that the primary series can be started at 6 weeks of age and subsequent doses given at four-week intervals. The catch-up schedule, which provides information about the minimum age and interval for all routine childhood vaccinations, is available on the National Immunization Program Web site
Infants 6 to 12 months of age who are traveling to a developing country should be vaccinated against measles with either a monovalent measles vaccine or the standard MMR. Children who receive measles vaccine before 12 months still require two doses of MMR after 1 year of age. If a child has received one dose, the second dose can be administered after more than one month has elapsed.
Tetanus immunization should be updated every five years for travelers. A single booster dose of inactivated poliovirus vaccine (IPV) is recommended for adults who are traveling to a region where cases of polio are known to occur. You may also consider giving a booster dose to teenagers, whose immunity may be waning. As of September 2005, endemic polio cases had occurred in India, Pakistan, Afghanistan, Nigeria, and Niger, although imported disease has spread to many surrounding countries and has even reached Indonesia.
Parents who are moving to a developing country may ask about vaccinating their children overseas. Although some vaccines are available abroad, the full spectrum—including new vaccines, such as the conjugated polyvalent pneumococcal vaccine, and even not-so-new ones, such as H influenzae type B and hepatitis B vaccines—may not be available. Moreover, in developing countries, maintaining the cold chain to preserve vaccine potency can be challenging. Adults and children should be advised to obtain as many vaccinations as possible in the US or other developed countries. If vaccines are administered abroad, parents should investigate the reliability of the source.
Hepatitis A vaccine
Hepatitis A is the most common vaccine-preventable disease acquired abroad. The incidence is three to 20 infections for every 1,000 person-months of travel.4 Children often have asymptomatic hepatitis A infection but can be an important reservoir for transmission for several months.
Hepatitis A is spread by the fecal-oral route without any known intermediate reservoir. Hand washing and avoiding contaminated food should therefore decrease the risk of exposure to the virus. In addition, highly effective and well-tolerated vaccines are available to prevent infection (Table 1). Travelers to countries with a high incidence of hepatitis A—which include most countries outside the United States, Canada, Western Europe, and Australia—should be vaccinated against the virus.