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.