QuickVue Influenza A+B rapid test for influenza surveillance in community

Abstract

BackgroundRapid diagnosis of influenza not only facilitates timelyclinical management, time series test results can alsoserve for disease surveillance purpose. We evaluated theperformance of a community based system using Quick-Vue Influenza A+B test (Quidel Corp., San Diego,California) for influenza surveillance in Hong Kong.MethodsAs part of a large community study, subjects older than2 years reporting at least two symptoms of influenza-like-illness were recruited from 30 outpatient clinics inHong Kong prospectively from February 2007 to July2010 around the influenza seasons [1,2]. Each subjectprovided a pooled pair of nose and throat swabs to betested by the QuickVue rapid test on site. Overall testpositive rate were weekly aggregated and compared witha hospital laboratory surveillance system (Weekly influ-enza virus isolation rate from the Queen Mary Hospital,Hong Kong) and a pre-existing community influenzasentinel surveillance system (Weekly consultation rate ofinfluenza-like illness reported by general practitioners inprivate practice from the Centre of Health Protection,Department of Health, HKSAR).ResultsA total of 5,824 subjects were recruited throughout thestudy. We define each study week as either high influ-enza activity or low influenza activity using fixed thresh-olds after removing extreme values two standarddeviations above the mean. The sensitivity of QuickVuedata for picking up high influenza activity was 78%when compare with the laboratory data and was 100%when comparing with the community data.ConclusionAlthough the sensitivity of QuickVue Influenza A+B testdecreases with specimen viral load, in which may missout mild influenza infection cases [3], its excellent speci-ficity allows more accurate influenza surveillance whencompare with other syndromic based systems. Its point-of-care usage and easy-to-use nature also increase theflexibility and popularity for disease surveillance, espe-cially in resource limited setttings where laboratoryfacilities and expertise are not available.