Epidemiological and clinical features of human coronavirus infections among different subsets of patients

Background Epidemiological and clinical data of human coronaviruses (HCoVs) infections are restricted to span 1-3 years at most. We conducted a comprehensive 9-year study on HCoVs by analyzing 1137 respiratory samples from four subsets of patients (asymptomatic, general community, with comorbidities, and hospitalized) in Sao Paulo, Brazil. Methods A pan-coronavirus RT-PCR screening assay was performed, followed by species-specific real-time RT-PCR monoplex assays. Results Human coronaviruses were detected in 88 of 1137 (7.7%) of the samples. The most frequently detected HCoV species were NL63 (50.0%) and OC43 (27.3%). Patients with comorbidities presented the highest risk of acquiring coronavirus infection (odds ratio = 4.17; 95% confidence interval = 1.9-9.3), and children with heart diseases revealed a significant HCoV infection presence. Dyspnea was more associated with HCoV-229E infections (66.6%), and cyanosis was reported only in HCoV-OC43 infections. There were interseasonal differences in the detection frequencies, with HCoV-229E being predominant in the year 2004 (61.5%) and HCoV-NL63 (70.8%) in 2008. Conclusions Our data provide a novel insight into the epidemiology and clinical knowledge of HCoVs among different subsets of patients, revealing that these viruses may cause more than mild respiratory tract disease.