Immunization for International Travelers

Chung, Moon Hyun

Abstract

In 2006, the annual number of Koreans traveling internationally increased to 11 million. With this increased number of Koreans traveling to developing countries, various infectious diseases have been reported to be imported into Korea. Immunization is an important tool for the prevention of such diseases. Vaccination offered to international travelers is divided into 3 categories, i.e., obligatory vaccination, vaccines against diseases with an increased risk in developing countries, and routine vaccination. Vaccination that is obligatory for travelers includes yellow fever vaccine for travelers entering yellow fever-endemic areas and meningococcal vaccination for pilgrims traveling to Saudi Arabia. Recent reports of the adverse event following yellow fever vaccination, i.e., vaccine-associated viscerotropic disease, pose a caution in the administration of yellow fever vaccine to the elderly or individuals with thymic diseases. Protein-conjugated meningococcal vaccines are generally preferred; however, polysaccharide vaccines are also effective in short-term travelers. The vaccinations recommended for the health of travelers include administration of hepatitis A (HAV), meningococcal, typhoid, rabies, tick-borne encephalitis, and plague vaccines. As many young Korean adults lack immunity against hepatitis A, the administration of the HAV vaccine is recommended for all Korean individuals in their 20s and all Korean seronegative individuals in their 30s. The risk of acquiring typhoid fever is high among travelers traveling to the rural areas of developing countries for 2 weeks or more. The rabies vaccine may be recommended for travelers traveling for longer than 3 months and animal handlers. Both tick-borne encephalitis and plague are rarely encountered among Korean travelers; furthermore, vaccines for these diseases are not available in Korea. As Japanese encephalitis is endemic in Korea, vaccination against encephalitis is not essential for Korean adults. Pre-travel counseling is an important opportunity for catch-up vaccination of healthy travelers who missed routine vaccinations.