Epidemiological Characteristics and Secondary Transmission of COVID-19 Among Inpatients and Healthcare Workers in a Single Hospital in Korea

Background: This study investigates the epidemiological characteristics of confirmed cases of COVID-19, including among inpatients and healthcare workers (HCWs), and identifies factors associated with secondary transmission within a single hospital in Korea.Methods: We retrospectively analyzed epidemiological investigation data from January 2020 to August 2022.Descriptive statistics and multivariate logistic regression were used to evaluate characteristics and identify risk factors for secondary transmission.Results: A total of 208 inpatients and 1,699 HCWs were diagnosed with COVID-19.Secondary infections occurred in 26.4% of inpatients and 9.7% of HCWs.Among inpatients, age 65 years (aOR: 11.31, 95% CI: 1.45-88.23),presence of respiratory symptoms (aOR: 0.27, 95% CI: 0.10-0.76),and ICU admission (aOR: 0.11, 95% CI: 0.01-0.88)were significantly associated with secondary transmission.Among HCWs, being aged 55-64 years (aOR: 1.83, 95% CI: 1.13-2.95)was a significant risk factor.Notably, asymptomatic cases had significantly higher numbers of close contacts than symptomatic cases.Conclusion: Our findings highlight the need for continued epidemiological surveillance and tailored infection control strategies, including proactive management of asymptomatic cases, targeted training for HCWs, and enhanced infection prevention protocols for inpatients to reduce in-hospital transmission of COVID-19.