An outbreak of influenza A (H1N1) virus in a remote Aboriginal community post-pandemic: Implications for pandemic planning and health service policy

Objective: To describe a 2013 outbreak of pandemic influenza A (H1N1) virus in a remote Western Australian Aboriginal community; inform outbreak prevention and control measures and discuss the community susceptibility to H1N1, three years after the A(H1N1)pdm09 pandemic. Methods: Records at the local clinic were used to classify cases as 'confirmed' (laboratory test positive for H1N1 or temperature >38 C with cough and/or sore throat) or 'probable' (self-reported fever with cough and/or sore throat). Additional data were collected from medical records and public health databases. Results: A total of 108 individuals met case definitions. Clinical attack rate was 23%. Children under five years of age had the highest age-specific attack rate (545 per 1,000 population). Thirty cases (28%) experienced complications with six (5.6%) requiring aero-evacuation. Only 7% of the community had received H1N1-containing vaccine during the previous year. No H1N1 cases from the community were previously reported. Conclusions: This is the first description of the effects of a novel influenza strain on a remote Australian Aboriginal community. Isolation and low vaccination are likely explanations for the apparent naivety to H1N1. Implications: There may be other remote communities at risk of H1N1. High attack and complication rates confirm that Aboriginal Australians should be prioritised in pandemic planning.