See the Editorial by Robert Steffen, pp. 1–3 of this issue.
Latitudinal Patterns of Travel Among Returned Travelers With Influenza: Results From the GeoSentinel Surveillance Network, 1997–2007
Article first published online: 8 DEC 2011
© 2011 International Society of Travel Medicine
Journal of Travel Medicine
Volume 19, Issue 1, pages 4–8, January/February 2012
How to Cite
Boggild, A. K., Castelli, F., Gautret, P., Torresi, J., von Sonnenburg, F., Barnett, E. D., Greenaway, C. A., Lim, P.-L., Schwartz, E., Wilder-Smith, A., Wilson, M. E. and for the GeoSentinel Surveillance Network (2012), Latitudinal Patterns of Travel Among Returned Travelers With Influenza: Results From the GeoSentinel Surveillance Network, 1997–2007. Journal of Travel Medicine, 19: 4–8. doi: 10.1111/j.1708-8305.2011.00579.x
- Issue published online: 5 JAN 2012
- Article first published online: 8 DEC 2011
Background. Influenza is a common vaccine-preventable disease among international travelers, but few data exist to guide use of reciprocal hemisphere or out-of-season vaccines.
Methods. We analyzed records of ill-returned travelers in the GeoSentinel Surveillance Network to determine latitudinal travel patterns in those who acquired influenza abroad.
Results. Among 37,542 ill-returned travelers analyzed, 59 were diagnosed with influenza A and 11 with influenza B. Half of travelers from temperate regions to the tropics departed outside influenza season. Twelve travelers crossed hemispheres from one temperate region to another, five during influenza season. Ten of 12 travelers (83%) with influenza who crossed hemispheres were managed as inpatients. Proportionate morbidity estimates for influenza A acquisition were highest for travel to the East-Southeast Asian influenza circulation network with 6.13 (95% CI 4.5–8.2) cases per 1000 ill-returned travelers, a sevenfold increased proportionate morbidity compared to travel outside the network.
Conclusions. Alternate hemisphere and out-of-season influenza vaccine availability may benefit a small proportion of travelers. Proportionate morbidity estimates by region of travel can inform pre-travel consultation and emphasize the ease of acquisition of infections such as influenza during travel.