title: Influenza epidemiology, vaccine coverage and vaccine effectiveness in sentinel Australian hospitals in 2012: the Influenza Complications Alert Network (FluCAN).
abstract: Influenza is mostly a mild, self-limiting infection and severe infection requiring hospitalisation is uncommon. Immunisation aims to reduce serious morbidity and mortality. The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at 15 sites across all states and territories in Australia. This study reports on the epidemiology of hospitalisation with confirmed influenza, estimate vaccine coverage and influenza vaccine protection against hospitalisation with influenza during the 2012 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals with influenza confirmed by nucleic acid detection. Controls were patients who had acute respiratory illnesses who were test-negative for influenza. Vaccine effectiveness was estimated as 1 minus the odds ratio of vaccination in case patients compared with control patients, after adjusting for known confounders. During the period 9 April to 31 October 2012, 1,231 patients were admitted with confirmed influenza at the 15 FluCAN sentinel hospitals. Of these, 47% were more than 65 years of age, 8% were Indigenous Australians, 3% were pregnant and 76% had chronic co-morbidities. Influenza A was detected in 83% of patients. Vaccination coverage was calculated from the vaccination status of 1,216 test negative controls and was estimated at 77% in patients 65 years or over and 61% in patients with chronic comorbidities. Vaccination effectiveness was estimated at 41% (95% CI: 28%, 51%, P&lt;0.001). Vaccine coverage was incomplete in at-risk groups, particularly non-elderly patients with medical comorbidities. The study results suggest that the seasonal influenza vaccine was moderately protective against hospitalisation with influenza during the 2012 season.
authors.affiliation: Alfred Health; Monash University, Melbourne, Victoria.
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
authors.affiliation: University of Western Australia, Perth, Western Australia; Royal Perth Hospital, Perth, Western Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Brown
authors.affiliation: University of Western Australia, Perth, Western Australia; Royal Perth Hospital, Perth, Western Australia.
authors.forename: Grant
authors.initials: G
authors.lastname: Waterer
authors.affiliation: Royal Adelaide Hospital, Adelaide, South Australia; University of Adelaide, Adelaide, South Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Holmes
authors.affiliation: Australian National University, Acton, Australian Capital Territory; The Canberra Hospital, Garran, Australian Capital Territory.
authors.forename: Sanjaya
authors.initials: S
authors.lastname: Senenayake
authors.affiliation: Barwon Health, Geelong, Victoria.
authors.forename: N Deborah
authors.initials: ND
authors.lastname: Friedman
authors.affiliation: Alice Springs Hospital, Alice Springs, Northern Territory.
authors.forename: Saliya
authors.initials: S
authors.lastname: Hewagama
authors.affiliation: Cairns Base Hospital, Cairns, Queensland.
authors.forename: Graham
authors.initials: G
authors.lastname: Simpson
authors.affiliation: University of Newcastle, Newcastle, New South Wales; John Hunter Hospital, Newcastle, New South Wales.
authors.forename: Peter
authors.initials: P
authors.lastname: Wark
authors.affiliation: Princess Alexandra Hospital, Brisbane, Queensland; University of Queensland, Brisbane, Queensland.
authors.forename: John
authors.initials: J
authors.lastname: Upham
authors.affiliation: Monash Medical Centre, Melbourne, Victoria.
authors.forename: Tony
authors.initials: T
authors.lastname: Korman
authors.affiliation: University of Sydney, Sydney, New South Wales; Westmead Hospital, Sydney, New South Wales.
authors.forename: Dominic
authors.initials: D
authors.lastname: Dwyer
authors.affiliation: University of Tasmania, Hobart, Tasmania.
authors.forename: Richard
authors.initials: R
authors.lastname: Wood-Baker
authors.affiliation: Royal Melbourne Hospital, Melbourne, Victoria; University of Melbourne, Melbourne, Victoria.
authors.forename: Louis
authors.initials: L
authors.lastname: Irving
authors.affiliation: Mater Hospitals, Brisbane, Queensland.
authors.forename: Simon
authors.initials: S
authors.lastname: Bowler
authors.affiliation: Alfred Health; Monash University, Melbourne, Victoria.
authors.forename: Tom
authors.initials: T
authors.lastname: Kotsimbos
authors.affiliation: ACT Health Directorate, Canberra, Australian Capital Territory.
authors.forename: Paul
authors.initials: P
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002648:Child; D015897:Comorbidity; D003428:Cross Infection; D005260:Female; D049674:History, 21st Century; D006760:Hospitalization; D006761:Hospitals; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000266:history / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000276:immunology*; D011247:Pregnancy; D012307:Risk Factors; D012621:Seasons; D018571:Sentinel Surveillance; D014611:Vaccination; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines