Influenza epidemiology, vaccine coverage and vaccine effectiveness in children admitted to sentinel Australian hospitals in 2014: The influenza complications alert network (FluCAN)

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance programme operating in all states and territories in Australia. We summarise the epidemiology of children hospitalised with laboratory-confirmed influenza in 2014 and reports on the effectiveness of inactivated trivalent inactivated vaccine (TIV) in children. In this observational study, cases were defined as children admitted with acute respiratory illness (ARI) with influenza confirmed by PCR. Controls were hospitalised children with ARI testing negative for influenza. Vaccine effectiveness (VE) was estimated as 1 minus the odds ratio of vaccination in influenza positive cases compared with test-negative controls using conditional logistic regression models. From April until October 2014, 402 children were admitted with PCR-confirmed influenza. Of these, 28% were aged < 1 year, 16% were Indigenous, and 39% had underlying conditions predisposing to severe influenza. Influenza A was detected in 90% of cases of influenza; influenza A(H1N1)pdm09 was the most frequent subtype (109/141 of subtyped cases) followed by A(H3N2) (32/141). Only 15% of children with influenza received antiviral therapy. The adjusted VE of one or more doses of TIV for preventing hospitalised influenza was estimated at 55.5% (95% confidence intervals (CI): 11.6–77.6%). Effectiveness against influenza A(H1N1)pdm09 was high (91.6%, 95% CI: 36.0–98.9%) yet appeared poor against H3N2. In summary, the 2014 southern hemisphere TIV was moderately effective against severe influenza in children. Significant VE was observed against influenza A(H1N1)pdm0

Surveillance for severe influenza and COVID-19 in patients admitted to sentinel Australian hospitals in 2020: the Influenza Complications Alert Network (FluCAN)

Introduction: Influenza is a common cause of acute respiratory infection, and is a major cause of morbidity and mortality. Coronavirus disease 2019 (COVID-19) is an acute respiratory infection that emerged as a pandemic worldwide before the start of the 2020 Australian influenza season. This report summarises the epidemiology of hospitalisations with laboratory-confirmed influenza and COVID-19 during the 2020 influenza season in a sentinel surveillance system. Methods: The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at sites in all jurisdictions in Australia. Influenza and COVID-19 cases were defined as patients hospitalised at sentinel hospitals and confirmed by nucleic acid detection. Results: There were 448 patients with COVID-19 admitted between 16 March and 31 December 2020, and only 20 patients with influenza admitted between 1 April and 30 November 2020, to one of 22 FluCAN hospitals. Of the COVID-19 cases, 173 (39%) were > 65 years of age, 36 (8%) were children (< 16 years), 6 (1%) were Aboriginal and Torres Strait Islander peoples, 4 (1%) were pregnant and 289 (65%) had chronic comorbidities. COVID-19 hospital admissions peaked between weeks 13 and 15 (first wave) nationally, and again between weeks 31 and 35 (Victoria), with most admissions represented by those above 40 years of age. Discussion: There was an unusually low number of hospital admissions with laboratory-confirmed influenza in this season, compared to recent seasons. This is likely to be due to effective public health interventions and international border closures as a result of a rise in COVID-19 respiratory infections and associated hospitalisations

Influenza Epidemiology, Vaccine Coverage and Vaccine Effectiveness in Children Admitted to Sentinel Australian Hospitals in 2017: Results from the PAEDS-FluCAN Collaboration

Background In 2017, Australia experienced record influenza notifications. Two surveillance programs combined to summarize the epidemiology of hospitalized influenza in children and report on vaccine effectiveness (VE) in the context of a limited nationally funded vaccination program. Methods Subjects were prospectively recruited (April-October 2017). Case patients were children aged ≤16 years admitted to 11 hospitals with an acute respiratory illness and laboratory-confirmed influenza. Controls were hospitalized with acute respiratory illness and tested negative for influenza. VE estimates were calculated using the test-negative design. Results A total of 1268 children were hospitalized with influenza: 31.5% wer