[An outbreak of influenza A (H3N2) among hospitalized geriatric patients]

An outbreak of influenza A (H3N2) in a hospital where almost 90% of the inpatients are aged over 70 years is described. An increase of febrile episodes was seen during the period from January 29th to March 17th, 1992 in two of six wards paired sera, at the onset of fever and more than two weeks later, were obtained from patients in sixty-five episodes. Serum antibody titer to influenza A (H3N2) elevated over four times in 39 (60%) of 65. Influenza A (H3N2) virus was also isolated from seven patients. These results indicated an outbreak of influenza A (H3N2) in this population. Maximum body temperature was over 39 degrees C in 18 patients (46.2%) with influenza, and were significantly higher than that of the non-influenza patients. The duration of fever in 12 patients of 39 was longer than 8 days in 12 patients, and significantly longer than that of non-influenza cases. Bronchopneumonia was found in ten patients (25.6%). These results suggest that the influenza infection causes a high grade fever in geriatric patients and lasts longer than is commonly seen in patients with fever not associated with influenza. Influenza infection also frequently induces bronchopneumonia and may contribute to increase mortality in the elderly, especially in patients over 70 years old.