Page 24 - Epidemiological studies on tuberculosis control and respiratory viruses

Chapter 6
Abstract
Objective: To better understand the clinical significance of respiratory viruses, we investigated the prevalence, relative distribution and viral load of respiratory viruses in community and hospital populations by illness severity.
Methods: From 2011 to 2013, nasopharyngeal samples were collected during the influenza season from adult participants of the HELIUS study, a Dutch population- based, multi-ethnic cohort study. For comparison, routine diagnostic and demographic data were used of adult patients presenting at a hospital serving the geographical area of the cohort study. Study participants were grouped by approximated illness severity: asymptomatic and mildly symptomatic HELIUS participants and hospital outpatients, inpatients, and ICU-admitted patients. Respiratory viruses were detected by multiplex real-time PCR. Crossing point values were used to estimate viral load.
Results: Respiratory viruses were detected in 12% of the community population and 31% of the hospital population. Among virus-positive subjects, rhinovirus (RV), human coronavirus (hCoV) and human bocavirus were significantly overrepresented in the community population, while the reverse was true for influenza A virus (InfA) and human metapneumovirus. Viral load of InfA and RSV was significantly correlated with illness severity. Correlations were less clear for RV and hCoV but highest viral loads were observed in ICU-admitted patients.
Conclusion: Differences in distribution between community and hospital populations confirm differences in pathogenicity between respiratory viruses in adults. Viral load correlated with illness severity for InfA and RSV but this was less clear for viruses with reduced pathogenicity, like RV and hCoV. Determining the clinical significance of such viruses in individual hospitalized patients remains challenging.
94