Background:  Human coronaviruses (CoV) are significant causes etiological factors of respiratory tract infections.  There are four major subgroups of CoVs, known as alpha, beta, gamma and delta. Four types of endemic human CoVs are 229E, OC43, NL63 and HKU1.

Aims and Objectives: In this retrospective study, we aimed to analyze the results of the respiratory samples of hospitalized patients by Real-Time(RT) PCR for CoVs 229E, NL63,OC43 and HKU1.

Methodology: Hospitalized patients with respiratory symptoms, including nasal congestion, rhinorrhea, nasal discharge, sneezing, sore throat and cough, were tested by RT PCR between April 2018 and March 2020. We retrospectively investigated the results of 1422 respiratory samples including 1245 nasopharyngeal swabs and 177 BAL samples. Detection rate and subtypes of CoV among upper and lower respiratory samples were retrospectively analyzed from patient records.

Results: Patients were between 0-93 years with a mean age of 26 years. We detected 142 (11,4%) CoVs in 1245 nasopharyngeal samples and 21 CoVs (11,9%) in 177 BAL samples. Most common CoV was OC43 (n=72, 44,2%) in overall samples.

Conclusion: Although CoV infections are predominant in the winter season, they are diagnosed throughout the year with lower incidence in summer and are identified in individuals of all ages. Understanding the epidemiological and virological features of CoV infections is important to effectively control their burden.