Influenza epidemiology in patients admitted to sentinel Australian hospitals in 2016: the Influenza Complications Alert Network (FluCAN)

Abstract

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with laboratory-confirmed influenza during the 2016 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals with an acute respiratory illness with influenza confirmed by nucleic acid detection. Data are also collected on a frequency matched sample of influenza negative patients admitted with acute respiratory infection as a control group. During the period 1 April to 30 October 2016 (the 2016 influenza season), there were 1,952 patients admitted with confirmed influenza to one of 17 FluCAN sentinel hospitals. Of these, 46% were elderly (≥65 years), 18% were children (<16 years), 5% were Aboriginal and Torres Strait Islander Peoples, 3% were pregnant and 76% had chronic co-morbidities. A small proportion were due to influenza B (7%). Estimated vaccine coverage was 73% in the elderly (≥65 years), 51% in non-elderly adults with medical comorbidities and 15% in children (<16 years) with medical comorbidities. The estimated vaccine effectiveness in the target population was 13% (95% confidence interval (CI): -5% to 27%). There were a large number of hospital admissions detected with confirmed influenza in this national observational surveillance system in 2016 with case numbers similar to that reported in 2014 and 2015. Show more