Characteristics of endemic human coronavirus infections during times of covid-19 pandemic

Introduction: After the implementation of mitigation strategies during the COVID-19 pandemic, the incidence of respiratory viruses, including human coronaviruses (HCoV), experienced a significant decrease. The aim of this study is to characterize the epidemiology and clinical aspects of HCoV infections in ambulatory adults during COVID-19 pandemic times. Methods: descriptive, prospective, longitudinal study performed in a private hospital in La Plata, Buenos Aires, Argentina between November 2020 and October 2022; 458 outpatient adults with upper respiratory tract infections (URTI) were studied undergoing clinical and microbiological follow-up. Results: 44 (9.6%) subjects were positive by multiplex PCR for HCoV. 14 of them for 229E (31.8%), 13 for OC43 (29.5%), 11 for HKU-1 (25.1%) and 6 for NL63 (13.6%). A repeated PCR was positive for the same HCoV in 19 (57%) of 33 patients on day 3-5. No hospitalizations or deaths were reported. Discussion: Endemic HCoV caused a significant proportion of URTI among outpatient adults during COVID19-related restrictions times. An alternating pattern of circulation between alfa-HCoV and beta-HCoV was observed.