Epidemiological characteristics of 24 children cases of influenza A (H7N9) virus infection in China

Objective To understand the epidemiological and clinical characteristics of human infection with avian influenza A (H7N9) virus in children, and provide evidence for the prevention and control of H7N9 virus infection. Methods The data of children H7N9 virus infection cases reported through national disease reporting information system were used in this study to analyze their time, geographic and population distributions and their clinical characteristics. Results As of 31 August 2014,24 children cases of H7N9 virus infection were reported in 9 provinces in China. The case number was highest in Guangdong province (11 cases). The incidence curve showed an obvious peak in spring in 2014. Among the 24 cases, 7 had alive poultry exposures, 12 had alive poultry market exposures, 2 had contacts with confirmed H7N9 virus infection cases and 3 had no clear exposures mentioned above. Seven clustering of H7N9 infection cases in children were found in 5 provinces. The main manifestations of H7N9 virus infection at initial stage was influenza like symptoms. Pneumonia developed in 6 cases. No severe cases and deaths occurred. The medians of intervals between onset and medical care seeking, onset and treatment with oseltamivir, and onset and cure were 0 day, 1 day and 10 days. Strengthened surveillance and medical observation for close contacts were the main ways for the case finding. Conclusion The time and geographic distributions of H7N9 virus infections in children are similar to those in adults, but the children cases usually have milder symptoms compared with adult cases.