Clinical Features of Adult COVID-19 Patients without Risk Factors before and after the Nationwide SARS-CoV-2 B.1.617.2 (Delta)-variant Outbreak in Korea: Experience from Gyeongsangnam-do

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.

Risk Factors for Coronavirus Disease 2019 (COVID-19)-Associated Pulmonary Aspergillosis in Critically Ill Patients: A Nationwide, Multicenter, Retrospective Cohort Study

“… 29 In addition, no patients with completed vaccinations were included in this study. Because of the increased virulence of the Delta variant and the preventive effect of COVID-19 vaccination for severe disease, 30 31 the epidemiology and clinical characteristics of CAPA in the more recent period might be different from those in this study.…”

Clinical Time Delay Distributions of COVID-19 in 2020–2022 in the Republic of Korea: Inferences from a Nationwide Database Analysis

“…The World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic on 11 March 2020. The SARS-CoV-2 B.1.617.2 (Delta) variant, which was first detected in December 2020, had been dominant globally (since late December 2021) as well as in the Republic of Korea, where the detection rate increased from 1.4% in April 2021 to 90% in August 2021; however, the Omicron sub-lineage BA.1 variant had increasingly replaced the Delta variant by late January 2022 [ 2 ].…”

Bean Extract-Based Gargle for Efficient Diagnosis of Active COVID-19 Infection Using Rapid Antigen Tests

“…The Alpha (B.1.1.7) and Delta (B.1.617.2) variants were spreading at a high rate in many countries, as well as in South Korea, during the study period ( 36 ). Compared with the NPS-RT-PCR results, we found the performance of the BG-RT-PCR within 6 days of illness to be 100% sensitive and specific for SARS-CoV-2, including the Alpha and Delta variants, suggesting a high sensitivity of BG-RT-PCR with comparable ability to NPS-RT-PCR.…”