Abstract
Background: Data on severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) delta variant virulence are insufficient. We retrospectively compared the clinical features of adult coronavirus disease 2019 (COVID-19) patients without risk factors for severe COVID-19 who entered residential treatment centers (RTCs) before and after the delta variant outbreak.
Methods: We collected medical information from two RTCs in South Korea. On the basis of nationwide delta variant surveillance, we divided the patients into two groups: 1) the delta-minor group (diagnosed from December 2020-June 2021, detection rate < 10%) and 2) the delta-dominant group (diagnosed during August 2021, detection rate > 90%). After propensity-score matching, the incidences of pneumonia, hospital transfer and need for supplemental oxygen were compared between the groups. In addition, risk factors for hospital transfer were analysed.
Results: A total of 1,915 patients were included. The incidence of pneumonia (14.6% vs. 9.2%, P = 0.009), all-cause hospital transfer (10.4% vs. 6.3%, P = 0.020) and COVID-19-related hospital transfer (7.5% vs. 4.8%, P = 0.081) were higher in the delta-dominant group than those in the delta-minor group. In the multivariate analysis, the delta-dominant group was an independent risk factor for all-cause (adjusted odds ratio [aOR], 1.91; 95% confidence interval [CI], 1.16-3.13; P = 0.011) and COVID-19-related hospital transfer (aOR, 1.86; 95% CI, 1.04-3.32; P = 0.036).
Conclusion: Hospitalization rates were increased in the adult COVID-19 patients during the delta variant nationwide outbreak. Our results showed that the delta variant may be more virulent than previous lineages.
Keywords: COVID-19; Delta Variant; Hospitalization; South Korea; Virulence.
【저자키워드】 COVID-19, Hospitalization, delta variant, virulence, South Korea, 【초록키워드】 Treatment, coronavirus disease, SARS-CoV-2, Coronavirus disease 2019, Risk factors, severe COVID-19, Pneumonia, hospital, variant, Delta, oxygen, risk factor, delta variant, Clinical features, Severe acute respiratory syndrome, Surveillance, outbreak, Patient, incidence, information, virulence, South Korea, lineages, detection rate, clinical feature, Multivariate analysis, Analysis, supplemental oxygen, adjusted odds ratio, two groups, 95% CI, 95% confidence interval, transfer, South, independent risk factor, adult COVID-19 patients, virulent, collected, the patient, addition, diagnosed, analysed, groups, RTC, adult COVID-19 patient, 【제목키워드】 SARS-CoV-2, B.1.617.2, clinical, experience, Factor,