Upper respiratory tract specimens collected from patients with SARI or ILI were tested for influenza virus, parainfluenza virus types 1–3, respiratory syncytial virus, adenovirus, rhinovirus, human metapneumovirus, enterovirus, S pneumoniae, Haemophilus influenzae type B, Bordetella pertussis, Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella spp. In addition, blood samples and induced sputa were collected from patients with SARI and tested for the detection of S pneumoniae and Mycobacterium tuberculosis, respectively. All test were implemented using polymerase chain reaction assays with the exception of tuberculosis, whereby a combination of tests was used. Sample collection and laboratory procedures are detailed in the Supplementary Material.