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Observational Study
. 2021 Dec 20;36(49):e341.
doi: 10.3346/jkms.2021.36.e341.

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

Byung-Han Ryu  1 , Sun In Hong  1 , Su Jin Lim  2 , Younghwa Cho  3 , Cheolgu Hwang  4 , Hyungseok Kang  5 , Si-Ho Kim  6 , Yu Mi Wi  6 , Kyung-Wook Hong  7 , In-Gyu Bae  7 , Oh-Hyun Cho  1   8
Affiliations
Observational Study

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

Byung-Han Ryu et al. J Korean Med Sci. .

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.

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Conflict of interest statement

The authors have no potential conflicts of interest to disclose.

Figures

Fig. 1
Fig. 1. Kaplan-Meier curves for all-cause (A) and COVID-19-related hospital transfer (B) in the propensity-score-matched cohort.
COVID-19 = coronavirus disease 2019.
See this image and copyright information in PMC

References

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