Clinical and laboratory predictors of influenza infection among individuals with influenza-like illness presenting to an urban Thai hospital over a five-year period

Early diagnosis of influenza infection maximizes the effectiveness of antiviral medicines. Here, we assess the ability for clinical characteristics and rapid influenza tests to predict PCR-confirmed influenza infection in a sentinel, cross-sectional study for influenza-like illness (ILI) in Thailand. Participants meeting criteria for acute ILI (fever > 38°C and cough or sore throat) were recruited from inpatient and outpatient departments in Bangkok, Thailand, from 2009-2014. The primary endpoint for the study was the occurrence of virologically-confirmed influenza infection (based upon detection of viral RNA by RT-PCR) among individuals presenting for care with ILI. Nasal and throat swabs were tested by rapid influenza test (QuickVue) and by RT-PCR. Vaccine effectiveness (VE) was calculated using the case test-negative method. Classification and Regression Tree (CART) analysis was used to predict influenza RT-PCR positivity based upon symptoms reported. We enrolled 4572 individuals ...流感感染的早期诊断可最大化抗病毒药物的临床疗效。本研究针对泰国的流感样病例（Influenza-like Illness, ILI）开展一项哨点横断面研究，旨在评估临床特征与快速流感检测手段预测经病毒学确认的流感感染的能力。 2009年至2014年间，研究人员从泰国曼谷的住院与门诊科室招募符合急性流感样病例判定标准（体温＞38℃且伴有咳嗽或咽痛）的参与者。本研究的主要终点为因流感样症状就诊的人群中，经逆转录聚合酶链反应（Reverse Transcription Polymerase Chain Reaction, RT-PCR）检测病毒RNA确诊的流感感染的发生情况。 研究人员对采集的鼻咽拭子与咽拭子分别开展快速流感检测（QuickVue）与RT-PCR检测。疫苗有效性（Vaccine Effectiveness, VE）采用病例-检测阴性法进行计算。本研究采用分类与回归树（Classification and Regression Tree, CART）分析方法，基于参与者报告的症状预测RT-PCR检测阳性的流感感染情况。本研究共纳入4572名参与者……