Dual Seasonal Patterns for Influenza, China

Li-Qun Fang,Wu-Chun Cao,Yan Gao,Yue-Long Shu,Sake J De Vlas,Jan Hendrik Richardus

doi:10.3201/eid1604.091578

Abstract

Dual Seasonal Patterns for Influenza, China

Highlights

Sentinel hospitals were required to collect 5–15 nasopharyngeal swabs each week from influenza-like illness (ILI) patients who had not taken antiviral drugs and who had fever (>38°C) for no longer than 3 days
In southern China, influenza is prevalent throughout the year; it has a clear peak in the summer and a less pronounced peak in the winter
Because this dual seasonal pattern of influenza has not been reported outside China and is relevant to pandemic (H1N1) 2009, we describe surveillance data for rates of consultation for influenza-like illness (ILI) and influenza subtypes in patients with ILI

Summary

Introduction

Sentinel hospitals were required to collect 5–15 nasopharyngeal swabs each week from ILI patients who had not taken antiviral drugs and who had fever (>38°C) for no longer than 3 days. Mainland China was divided into northern and southern parts, basically following the Qinling Mountain range in the west and the Huai River in the east. The prominent influenza peaks in the winter in the north and summer in the

Results

Conclusion