title: Influenza epidemiology, vaccine coverage and vaccine effectiveness in sentinel Australian hospitals in 2013: the Influenza Complications Alert Network.
abstract: The National Influenza Program aims to reduce serious morbidity and mortality from influenza by providing public funding for vaccination to at-risk groups. The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at 14 sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with confirmed influenza, estimates vaccine coverage and influenza vaccine protection against hospitalisation with influenza during the 2013 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals, with influenza confirmed by nucleic acid testing. 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 5 April to 31 October 2012, 631 patients were admitted with confirmed influenza at the 14 FluCAN sentinel hospitals. Of these, 31% were more than 65 years of age, 9.5% were Indigenous Australians, 4.3% were pregnant and 77% had chronic co-morbidities. Influenza B was detected in 30% of patients. Vaccination coverage was estimated at 81% in patients more than 65 years of age but only 49% in patients aged less than 65 years with chronic comorbidities. Vaccination effectiveness against hospitalisation with influenza was estimated at 50% (95% confidence interval: 33%, 63%, P<0.001). We detected a significant number of hospital admissions with confirmed influenza in a national observational study. Vaccine coverage was incomplete in at-risk groups, particularly non-elderly patients with medical comorbidities. Our results suggest that the seasonal influenza vaccine was moderately protective against hospitalisation with influenza in the 2013 season.
authors.affiliation: Alfred Health; Monash University, Melbourne, Victoria.
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
authors.affiliation: University of Sydney, Sydney, New South Wales and Westmead Hospital, Sydney, New South Wales.
authors.forename: Dominic E
authors.initials: DE
authors.lastname: Dwyer
authors.affiliation: Royal Adelaide Hospital, Adelaide, South Australia and University of Adelaide, Adelaide, South Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Holmes
authors.affiliation: Royal Melbourne Hospital, Melbourne, Victoria and University of Melbourne, Melbourne, Victoria.
authors.forename: Lois B
authors.initials: LB
authors.lastname: Irving
authors.affiliation: University of Western Australia, Perth, Western Australia and Royal Perth Hospital, Perth, Western Australia.
authors.forename: Simon Ga
authors.initials: SG
authors.lastname: Brown
authors.affiliation: University of Western Australia, Perth, Western Australia and Royal Perth Hospital, Perth, Western Australia.
authors.forename: Grant W
authors.initials: GW
authors.lastname: Waterer
authors.affiliation: Monash Medical Centre, Melbourne, Victoria.
authors.forename: Tony M
authors.initials: TM
authors.lastname: Korman
authors.affiliation: Royal Hobart Hospital, Hobart, Tasmania.
authors.forename: Cameron
authors.initials: C
authors.lastname: Hunter
authors.affiliation: Alice Springs Hospital, Alice Springs, Northern Territory.
authors.forename: Saliya
authors.initials: S
authors.lastname: Hewagama
authors.affiliation: Barwon Health, Geelong, Victoria.
authors.forename: Nadia D
authors.initials: ND
authors.lastname: Friedman
authors.affiliation: University of Newcastle, Newcastle, New South Wales and John Hunter Hospital, Newcastle, New South Wale.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Wark
authors.affiliation: Cairns Base Hospital, Cairns, Queensland.
authors.forename: Graham
authors.initials: G
authors.lastname: Simpson
authors.affiliation: Princess Alexandra Hospital, Brisbane, Queensland and University of Queensland, Brisbane, Queensland.
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
authors.affiliation: Mater Hospitals, Brisbane, Queensland.
authors.forename: Simon D
authors.initials: SD
authors.lastname: Bowler
authors.affiliation: Australian National University, Acton, Australian Capital Territor and The Canberra Hospital, Garran, Australian Capital Territory.
authors.forename: Sanjaya N
authors.initials: SN
authors.lastname: Senenayake
authors.affiliation: Alfred Health; Monash University, Melbourne, Victoria.
authors.forename: Tom C
authors.initials: TC
authors.lastname: Kotsimbos
authors.affiliation: ACT Health Directorate, Canberra, Australian Capital Territory.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002648:Child; D015897:Comorbidity; D005260:Female; D049674:History, 21st Century; D006760:Hospitalization; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000266:history / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D063868:Patient Outcome Assessment; D011247:Pregnancy; D012307:Risk Factors; D018571:Sentinel Surveillance; D012720:Severity of Illness Index; D014611:Vaccination; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines