Epidemiological analysis of influenza A (H1N1) pdm09 in Hebei Province from 2011 to 2017

Abstract

Objective This study aimed to analyze the epidemiological characteristics of influenza A (H1N1) pdm09 in Hebei province so as to provide scientific basis for its prevention and control. Methods The analysis was conducted on the data of cases of influenza and influenza-like illness (ILI) in Hebei province from April 2011 to March 2017, which were collected from the Chinese National Influenza Surveillance Network. Results A total of 77 008 specimens were collected and 2 699 (positive rate of 3.50%) were positive for influenza A (H1N1) pdm09. Further analysis to the 2 699 cases of A (H1N1) pdm09 showed that cases could be detected in all 11 regions. The male to female ratio was 1.09:1. The highest detection rate was in the 25 ~ 59 years old group, and the lowest was in the 0 ~ 4 years old group. From April 2011 to March 2017, there were four epidemics of influenza A (H1N1) pdm09 with obvious seasonality and one single peak in each epidemic. It was showed that the influenza A (H1N1) pdm09 cases could be detected each year, and it was the dominant pathogen of influenza virus in these surveillance years ( 2012-2013, 2013-2014, 2016-2017) . Conclusions The prevalence of influenza A (H1N1) pdm09 in Hebei province had an obvious seasonality (in winter and spring), and the infections were intensive in the age group of 5 ~ 14 years old in the past few years. Key words: Influenza-like illness; Influenza A(H1N1)pdm09; Epidemiological characteristics