Epidemiological Characteristics of Common Human Coronaviruses in Korea, 2015-2019

Abstract Background: Compared to influenza virus and respiratory syncytial virus, common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs in Korea, we aimed to describe epidemiological characteristics of common HCoVs. Methods: Respiratory viral test results from more than 67,000 respiratory samples from the two data sources, Korea Influenza and Respiratory Viruses Surveillance System (KINRESS, N=58,253) and Seoul National University Children’s Hospital (SNUCH, N=9,589) were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex RT-PCR. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs in SNUCH. Results: Of the 67,842 samples tested, 1 or more respiratory viruses were detected from 35,459 (52.2%) samples and 2,854 (4.2%) samples were positive for HCoVs (OC43 2.1%, NL63 1.7%, 229E 0.4%). All 3 types were co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was most prevalent, peaking every winter. HCoV-NL63 circulated with alternate peaks occurring between January-March and November-February. Meanwhile, HCoV-229E had smaller peaks every other winter in 2015/2016 and 2017/2018. From the national surveillance data, HCoV infection was most prevalent among 0 to 1 year old children and older adults aged over 70 years. 18.2% of the HCoV-positive samples were co-detected with other respiratory viruses, with the highest co-detection rate (33.7%) in children 0 to 1 year of age and the lowest co-detection rate (3.6%) in adults ≥70 years old. Upper respiratory tract infection was the most common (60.0%) clinical diagnosis of the 135 previously healthy children. Croup accounted for 17.0% of NL63-positive childrenConclusion: This study described the epidemiological characteristics of 3 types of common HCoVs (OC43, NL63, 229E) in Korea; the highest prevalence of OC43, concurrent circulation during winter, and age difference in HCoV infection and co-detection rate with other respiratory virus. It may be informative to monitor any changes in the epidemiology of common HCoVs as the COVID-19 pandemic continues.