to the editor: The article “Travel Immunizations” provided an excellent overview of the vaccine-preventable illnesses.¹ I would like to make two points with respect to travel immunizations.

In addition to the obvious benefits of influenza vaccine for international travelers, physicians should consider an indication for the use of this vaccine in travelers to isolated Amerindian populations of the lowlands of South America. Such populations, with recent and minimal outside contact, suffer significant mortality as a consequence of contracting influenza and need to be protected from influenza introduced by travelers.

The authors correctly point out that analysis of recipients of the yellow fever vaccine in the United States from 1990 to 1998 indicated that persons 65 years or older were at increased risk for neurologic and systemic reactions. These adverse reactions appear to have occurred almost exclusively in first-time users of yellow fever vaccine who were older than 65 years, but not in those older than 65 years who underwent revaccination. A recent report in the Lancet² indicated that persons with a history of thymus disease or thymectomy are at greatest risk for developing multiple organ failure and should not be given yellow fever vaccine.

editor’s note: This letter was sent to the authors of “Travel Immunizations,” who declined to reply.