Journal des maladies infectieuses et de la thérapie

Abstrait

Changing Dynamics of SARS-CoV-2 B.1.617.2 (Delta Variant) Outbreak in the United Kingdom: Shifting of SARS-CoV-2 Infections from Younger to Elderly Populations with Increasing Hospitalizations and Mortality Among Elderly

Venkata R. Emani, Abirath S. Nakka, Kartik K. Goswami, Shaila R. Emani, Kailash R. Maddula, Nikhila K. Reddy, Nidhi K. Reddy, Dheeraj Nandanoor, Sanjeev Goswami, Raghunath Reddy

Background: To assess the comprehensive dynamics of outcomes during the SARS-CoV-2 B.1.617.2 (Delta variant) compared to the Alpha variant outbreak in the United Kingdom.

Methods: In this observational study of the cases reported by Public Health England for confirmed (sequencing and genotyping), SARS-CoV-2 cases Delta variant (n=592,692) and Alpha variant (n=150,934) were used. Outcomes were analyzed by age groups and compared with all reported weekly cases in the UK.

Results: The Delta variant surge is associated with a significantly lower case fatality rate (0.43% vs. 1.07; RR 0.39; 95% CI 0.37- 0.42; P<0.0001); lower odds of hospitalization (2.1% vs. 3.0%; RR 0.70; 95% CI 0.68-0.73; P<0.0001) than the Alpha variant. During the Delta variant surge there were significant increased cases (11.3% to 21.1%, RR 1.87; 95% CI 1.84-1.89; P<0.0001), hospitalizations (40.2% to 56.5%; RR 1.40, 95% CI 1.3-1.46; P<0.0001) among confirmed Delta variant cases in the ≥ 50 years age group during the August 3-September 12, 2021 period compared to earlier reported cases. There was also a significant increase in total weekly COVID-19 deaths noted among ≥ 70 years old age group (71.4% to 75.1%; RR 1.05; 95% CI 1.01-1.08; P=0.0028) during August 6-October 8, 2021 compared to June 4-July 30, 2021 period.

Conclusion: The Delta variant surge is associated with significantly lower mortality and hospitalizations than the Alpha variant. As the Delta variant surge progressed, ≥ 50 years old had a significant increased percentage of cases, hospitalizations and a significant increased COVID-19 deaths occurred among ≥ 70 years old age group.