Epidemiology of travel-associated pandemic (H1N1) 2009 infection in 116 patients, Singapore.
Bottom Line: One fourth of the case-patients traveled after illness onset, and 15% became ill while traveling.Case-patients on longer flights were more likely to become ill before arrival; those with shorter flights tended to become ill after arrival.Thermal scanners detected fevers in 12% of the arriving case-patients, resulting in a shorter time to isolation.
Affiliation: Tan Tock Seng Hospital, Singapore.
In June 2009, during Singapore's pandemic influenza plan containment phase, pandemic (H1N1) 2009 was introduced into the country through imported cases. To understand how travel patterns affected the initial outbreak, we examined epidemiologic and travel data for the first 116 case-patients admitted to Tan Tock Seng Hospital, Singapore, with travel-associated infection. Sixty-one percent and 54% of patients, respectively, met US Centers for Disease Control and Prevention and World Health Organization temperature criteria for influenza-like illness. One fourth of the case-patients traveled after illness onset, and 15% became ill while traveling. Regions of exposure for imported infections changed rapidly; case-patients initially arrived from North America, followed by Australasia and Southeast Asia. Case-patients on longer flights were more likely to become ill before arrival; those with shorter flights tended to become ill after arrival. Thermal scanners detected fevers in 12% of the arriving case-patients, resulting in a shorter time to isolation.
Related in: MedlinePlus
Mentions: As the pandemic shifted toward Asian ports of embarkation, the number of case-patients with travel durations of <8 hours increased (Figure 2, panel A). The time of symptom onset relative to arrival in Singapore is shown in Figure 2, panel B; the figure does not include information for patients who were symptomatic before embarkation. Time of symptom onset was progressively closer to the time of arrival in Singapore for those arriving from longer distances (p = 0.001). Patients with longer travel durations were also more likely to have onset of symptoms before arrival (p = 0.04).