Respiratory Virus Infections in Acutely Hospitalized Adult Patients With Pulmonary and Extrapulmonary Complications

Respiratory viruses cause severe infections, and contribute to a substantial number of hospitalizations, admission to intensive care units and deaths. Many hospitalizations due to respiratory virus infection are related to pneumonia or exacerbation of chronic lung disease. In addition, many hospitalizations are related to extrapulmonary complications, such as acute coronary syndrome or stroke. Previous studies have reported the incidence of respiratory viruses among patients with pulmonary complications, or the association of respiratory viruses with acute coronary syndrome or stroke. However, there are several problems associated with these studies. First, many of these studies are retrospective in nature, and therefore testing was only performed in selected patients with respiratory symptoms. Hence, many patients without respiratory symptoms were not recruited. Second, respiratory virus can be detected in some asymptomatic individuals. Therefore, the presence of respiratory virus may be an incidental finding rather than the cause of the complication. Third, many studies only focus on a few respiratory viruses, especially on influenza virus. This study aims to address these issues. The investigators propose to conduct a prospective cohort study. The investigators will recruit hospitalized adult patients with exacerbation of underlying lung disease, acute coronary syndrome or stroke. As controls, the investigators will recruit outpatients follow-up for chronic heart disease, chronic lung disease or neurological conditions. The investigators will collect saliva from study participants and perform respiratory virus testing using a multiplex PCR panel. Previous studies have shown that there is a high concordance between results from respiratory virus testing on saliva and nasopharyngeal specimens. The investigators will also use a standardized questionnaire to collect information regarding symptoms. This study will provide accurate data on the epidemiology of respiratory viruses in pulmonary and extrapulmonary complications.These data are important for clinicians, public health practitioners and scientists.