79 IMMUNIZATION AND ADVICE TO TRAVELERS
Harrison’s Manual of Medicine
IMMUNIZATION AND ADVICE TO TRAVELERS
Vaccines for Routine Use
Advice to Travelers
Vaccination against infectious diseases is one of the most potent and effective tools of medicine. Through immunization, many once-prevalent infectious diseases (e.g., smallpox, polio, measles, Haemophilus influenzae infection) have been eliminated or drastically curtailed. However, complacency and socioeconomic barriers have impeded the attainment of universal and appropriate immunization. Adults in particular often fail to receive indicated immunizations, such as pneumococcal vaccination, influenza vaccination, and tetanus-diphtheria boosters.
Active immunization refers to administration of a vaccine or a toxoid in order to elicit long-lasting protection. Live vaccines are usually contraindicated for pts who are immunosuppressed, febrile, or pregnant. Passive immunization refers to the provision of temporary immunity by administration of exogenously produced immune substances such as antibodies.
VACCINES FOR ROUTINE USE
ADULTS Recommendations for adult immunization are summarized in Table 79-1. Routine immunization against polio is not recommended for adults unless they are at particularly high risk of exposure (e.g., during travel to endemic regions) or are the guardians of a child with an immunodeficiency disorder. Rubella vaccine should be given to all women of childbearing age unless they have documented proof of immunization or have positive rubella antibody on laboratory testing. College students, particularly freshmen living in a dormitory, should be offered the option of immunization against meningococcal meningitis. A vaccine for Lyme disease is licensed for persons 15–70 years old. Its use is based on individual risk.
Table 79-1 Adult Immunization Schedule
IMMUNOCOMPROMISED STATES Immune responses may not be as vigorous in immunocompromised persons as in those with a normal immune system. Immunization of HIV-infected persons is summarized in Table 79-2. In other immunocompromised patients, including those receiving immunosuppressive therapy, passive immunization can be considered either as postexposure prophylaxis or as part of the treatment for established infection (Table 79-3).
Table 79-2 Recommendations for Routine Immunization of HIV-Infected Persons in the United States
Table 79-3 Recommended Postexposure Immunization with Immunoglobulin Preparations in the United States
POSTEXPOSURE IMMUNIZATION Active or passive immunization prevents or attenuates disease after exposure to certain infections. Recommended regimens are compiled in Table 79-3.
ADVICE TO TRAVELERS
Immunizations for travel are generally divided into three categories: routine (Table 79-1), required (mandated for entry into certain areas—e.g., yellow fever and meningococcal meningitis), and recommended (desirable but not required—e.g., hepatitis A and B, typhoid, meningococcal meningitis, Japanese encephalitis, cholera, and rabies). Vaccines commonly given to travelers are listed in Table 79-4.
Table 79-4 Vaccines Commonly Used for Travel
MALARIA Prevention of malaria, a major cause of life-threatening illness in travelers, should stress avoidance of mosquitoes by staying indoors and use of DEET-containing mosquito repellents. Table 79-5 lists the currently recommended drugs of choice for prophylaxis of malaria, by destination.
Table 79-5 Malaria Chemosuppressive Regimens According to Geographic Areaa
DIARRHEA Traveler’s diarrhea, which is usually caused by enterotoxigenic Escherichia coli but may also be caused by many other pathogens, can often be avoided by consuming only well-cooked hot foods, peeled or cooked fruits and vegetables, and bottled or boiled beverages. When diarrhea occurs without fever or bloody stool, it can be self-treated with a 3-day course of an oral quinolone. For diarrhea acquired in areas such as Thailand, where >70% of Campylobacter infections are quinolone-resistant, azithromycin is a better choice.
For a more detailed discussion, see Keusch GT, Bart KJ: Immunization Principles and Vaccine Use, Chap. 122, p. 780; and Keystone JS, Kozarsky PE: Health Advice for International Travel, Chap. 123, p. 793, in HPIM- 15.