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.
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.
Authors: Stuart Wood; Kalyani Telu; David Tribble; Anuradha Ganesan; Anjali Kunz; Mary Fairchok; Elizabeth Schnaubelt; Mark D Johnson; Ryan Maves; Jamie Fraser; Indrani Mitra; Tahaniyat Lalani; Heather C Yun Journal: Am J Trop Med Hyg Date: 2018-11 Impact factor: 2.345
Authors: M Goeijenbier; P van Genderen; B J Ward; A Wilder-Smith; R Steffen; A D M E Osterhaus Journal: J Travel Med Date: 2017-01-11 Impact factor: 8.490
Authors: Lance C Jennings; Patricia C Priest; Rebecca A Psutka; Alasdair R Duncan; Trevor Anderson; Patalee Mahagamasekera; Andrew Strathdee; Michael G Baker Journal: J Clin Virol Date: 2015-03-14 Impact factor: 3.168
Authors: Karin Leder; Joseph Torresi; Michael D Libman; Jakob P Cramer; Francesco Castelli; Patricia Schlagenhauf; Annelies Wilder-Smith; Mary E Wilson; Jay S Keystone; Eli Schwartz; Elizabeth D Barnett; Frank von Sonnenburg; John S Brownstein; Allen C Cheng; Mark J Sotir; Douglas H Esposito; David O Freedman Journal: Ann Intern Med Date: 2013-03-19 Impact factor: 25.391