Vaccination and immunization against travel-related diseases in immunocompromised hosts

Immunocompromised hosts are growing in number and include transplant recipients of solid organs or hematopoietic stem cells, people who have HIV, cancer patients on chemotherapy, patients on immunomodulatory treatments for rheumatologic, gastrointestinal or other conditions, as well as those with other immunocompromising conditions. As their overall health improves, they are more likely to initiate foreign travel and have potential exposures to endemic pathogens. Immunocompromised hosts are, in general, less likely to respond to vaccines and may be more likely to have side effects from certain vaccines, such as those containing live-attenuated virus. In addition, vaccines are immunomodulatory and could theoretically impact upon immunologic conditions. This review will summarize the medical literature regarding travel-related vaccines in the adult, immunocompromised-host population. Since the research in this realm is limited and exists primarily in the setting of solid-organ and hematopoietic stem cell transplant recipients and HIV-positive subjects, this review will largely focus on these populations.