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. 2021 Sep;26(35):2100793.
doi: 10.2807/1560-7917.ES.2021.26.35.2100793.

Vaccine effectiveness against infection with the Delta (B.1.617.2) variant, Norway, April to August 2021

Elina Seppälä  1   2 , Lamprini Veneti  3 , Jostein Starrfelt  3 , Anders Skyrud Danielsen  3 , Karoline Bragstad  4 , Olav Hungnes  4 , Arne Michael Taxt  1 , Sara Viksmoen Watle  1 , Hinta Meijerink  1
Affiliations
Free PMC article

Vaccine effectiveness against infection with the Delta (B.1.617.2) variant, Norway, April to August 2021

Elina Seppälä et al. Euro Surveill. 2021 Sep.
Free PMC article

Abstract

Some variants of SARS-CoV-2 are associated with increased transmissibility, increased disease severity or decreased vaccine effectiveness (VE). In this population-based cohort study (n = 4,204,859), the Delta variant was identified in 5,430 (0.13%) individuals, of whom 84 were admitted to hospital. VE against laboratory confirmed infection with the Delta variant was 22.4% among partly vaccinated (95% confidence interval (CI): 17.0-27.4) and 64.6% (95% CI: 60.6-68.2) among fully vaccinated individuals, compared with 54.5% (95% CI: 50.4-58.3) and 84.4% (95%CI: 81.8-86.5) against the Alpha variant.

Keywords: : COVID-19 Vaccines; B.1.617.2; Delta variant of concern; Norway; SARS-CoV-2; Vaccine effectiveness.

Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1
Number of notified cases of COVID-19 by week of positive test result and cumulative number of vaccinated individuals by vaccine status and week; percentage of whole genome sequenced or PCR-screened COVID-19 cases and percentage of cases diagnosed with SARS-CoV-2 Delta and Alpha variants, Norway, 15 April–15 August 2021
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