Abstract:
BACKGROUND : Viruses detected in patients with acute respiratory infections may be the
cause of illness or colonizers.
METHODS : We compared the prevalence of 10 common respiratory viruses (influenza A
and B viruses, parainfluenza virus 1, 2, and 3; respiratory syncytial virus (RSV);
adenovirus, rhinovirus, human metapneumovirus (hMPV) and enterovirus) in patients
hospitalized with severe acute respiratory illness (SARI), outpatients with influenza-like
illness (ILI), and control subjects who did not report any febrile, respiratory or
gastrointestinal illness during 2012-2015 in South Africa. We estimated the attributable
fraction (AF) and the detection rate attributable to illness for each of the different
respiratory viruses. RESULTS : We enrolled 1959 SARI, 3784 ILI and 1793 controls. Influenza virus (AF:
86.3%; 95%CI: 77.7%-91.6%), hMPV (AF: 85.6%%; 95%CI: 72.0%-92.6%), and RSV
(AF: 83.7%; 95%CI: 77.5%-88.2%) infections were highly associated with severe
disease, while rhinovirus (AF: 46.9%; 95%CI: 37.6%-56.5%) and adenovirus (AF:
36.4%; 95%CI: 20.6%-49.0%) were only moderately associated. The estimated
detection rate associated with severe disease was: 20.2% for rhinovirus, 16.7% for
RSV, 7.0% for adenovirus, 4.9% for influenza virus and 3.8% for hMPV. Similar
patterns were observed for patients with ILI. CONCLUSIONS : Influenza, RSV and hMPV can be considered likely pathogens if
detected in patients with ILI and SARI while rhinovirus and adenovirus were commonly
identified also among controls suggesting that they may cause only a proportion of
clinical disease observed in positive patients. Nonetheless, given their high estimated
detection rate attributable to illness, they may be important contributors to disease.
