Epidemiological characteristics of febrile outbreaks in Beijing during 2018-2019 influenza season

Objective To understand the epidemiology characteristic of febrile outbreaks in Beijing, so as to provide a scientific basis for influenza prevention. Methods The data of febrile outbreaks reported from 2018 to 2019 were collected. The epidemiological characteristics were described and analyzed by scales, time, places, pathogens and interventions of the outbreaks. Results In the 2018-2019 influenza season, a total of 742 febrile outbreaks were reported, and 85.64% were caused by the influenza virus. Two peaks were observed in the demension of time. The scales and attack rates of outbreaks in outer suburbs districts were higher than those in urban districts (P<0.05). The attack rate in child care facilities was greater than those in other places (P<0.01). According to laboratory tests, the outbreaks were mainly caused by influenza B/Victoria-Linage virus (39.09%), influenza A (H3N2) virus (21.82%) and influenza A (H1N1)pdm09 virus (20.17%). The differences in the distribution of types of influenza viruses in places and districts were statistically significant (p<0.05). Earlier intervention reduced the scales of outbreaks (r = 0.35, p<0.01). Conclusions The febrile outbreaks mainly occurred in primary schools and child care facilities. Early detection and intervention may reduce the scale of the outbreaks. Key words: Influenza; Febrile outbreaks; Epidemiological characteristics