Community respiratory viruses (CRVs) are commonly associated with seasonal infections. It has been associated with higher morbidity and mortality among children, elderly and immunosupressed patients.

In April 2009, the circulation of a new influenza A virus (FLUA H1N1v) was responsible for the first influenza pandemic of this century. In this study we report the clinical and epidemiological profile of inpatients infected with CRVs or with FLUA H1N1v at a tertiary hospital in southern Brazil. In addition, we evaluated this outline in survivor and nonsurvivor patients infected with FLUA H1N1v. Multiplex RT-PCR and real time RT-PCR were used to detect the presence of viruses from inpatients with respiratory infections. Records data from all patients were reviewed. A total of 171 patients were examined over a period of 16 weeks. Of these, 39% were positive for FLUA H1N1v, 36% for CRVs, and 25% were negative. Epidemiological data regarding median age (30 and 1.5 years), myalgia (44% and 13%), need for mechanical ventilation (44% and 9%) and mortality (35% and 9%) was statistically different for the FLUA H1N1v and CRV-infected patients. In a multivariate analysis comparing survivor and nonsurvivor patients infected with influenza A H1N1v, median age and CK levels were significantly associated with a severe outcome. Seasonal respiratory infections are a continuing concern.

Our results highlight the importance of studies on prevalence and severity of these infections, as well as investments in programs of clinical and laboratory monitoring are essential to detect the appearance of new infective agents.