Viruses causing lower respiratory symptoms in young children: findings from the ORChID birth cohort

Sarna, Mohinder; Lambert, Stephen B; Sloots, Theo P; Whiley, David M; Alsaleh, Asma; Mhango, Lebogang; Bialasiewicz, Seweryn; Wang, David; Nissen, Michael D; Grimwood, Keith; Ware, Robert S

study, 5 these investigations recruited either highly selected hospitalised children or outpatients as study cases, [6] [7] [8] or used controls from outpatient clinics. 6 7 A meta-analysis of 23 studies that calculated virus-specific AFEs included 22 studies employing hospital-based case ascertainment and only three using community-based controls. 9 Other studies comparing symptomatic and asymptomatic groups calculated odds ratios (ORs), [10] [11] [12] or relative risks, 13 without calculating AFEs. Moreover, several studies focused solely either on specific viruses 10 12 or outcomes. 6 11-13 Longitudinal, community-based studies employing sensitive molecular-based assays with regular and frequent sampling, irrespective of illness, are best suited to explore the relationship between respiratory virus detections and ARI symptoms, especially as they represent most ARI episodes. The aim of our study was to examine the disease-pathogen associations of respiratory viruses in infants participating in a community-based birth cohort project 14 and to calculate their virus-specific AFE values.