Preliminary Epidemiology of Human Infections with Highly Pathogenic Avian Influenza A

The authors compared characteristics of eight human infections of highly pathogenic Asian lineage A(H7N9) first identified in 2017 with human infections of low pathogenic Asian lineage A(H7N9) that have been occurring since 2013. They found the HPAI A(H7N9) patients significantly more likely to be hospitalized earlier, live in rural areas, and have exposure to sick or dead poultry. Statistical power to detect other differences in epidemiological characteristics or disease severity was limited by the small sample of HPAI A(H7N9) patients.