BNT162b2 and ChAdOx1 nCoV-19 vaccinations, incidence of SARS-CoV-2 infections and COVID-19 hospitalisations in Scotland in the Delta era

Abstract

Background The emergence of the B.1.617.2 Delta variant of concern was associated with increasing numbers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and COVID-19 hospital admissions. We aim to study national population level SARS-CoV-2 infections and COVID-19 associated hospitalisations by vaccination status to provide insight into the association of vaccination on temporal trends during the time in which the SARS-CoV-2 Delta variant became dominant in Scotland.

Methods We used the Scotland-wide Early Pandemic Evaluation and Enhanced
Surveillance (EAVE II) platform, covering the period when Delta was pervasive
(May 01 to October 23, 2021). We performed a cohort analysis of every vaccine-eligible individual aged 20 or over from across Scotland. We determined the vaccination coverage, SARS-CoV-2 incidence rate and COVID-19 associated
hospitalisations incidence rate. We then stratified those rates by age group, vaccination status (defined as “unvaccinated”, “partially vaccinated” (1 dose), or “fully vaccinated” (2 doses)), vaccine type (BNT162b2 or ChAdOx1 nCoV-19), and coexisting conditions known to be associated with severe COVID-19 outcomes.

Results During the follow-up of 4183022 individuals, there were 407405 SARS-CoV-2 positive cases with 10441 (2.6%) associated with a hospital admission.
Those vaccinated with two doses (defined as fully vaccinated in the current study) of either vaccine had lower incidence rates of SARS-CoV-2 infections and much lower incidence rates of COVID-19 associated hospitalisations than those unvaccinated in the Delta era in Scotland. Younger age groups were  substantially more likely to get infected. In contrast, older age groups were much more likely to be hospitalised. The incidence rates stratified by coexisting conditions were broadly comparable with the overall age group patterns.

Conclusions This study suggests that national population level vaccination was
associated with a reduction in SARS-CoV-2 infections and COVID-19 associated
hospitalisation in Scotland throughout the Delta era.

Rights

Copyright © 2022 The Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/ 4.0/).

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Identifiers

DOI

https://doi.org/10.7189/jogh.12.05008

Repository URI

http://hdl.handle.net/10023/25238