On the association between SARS-COV-2 variants and COVID-19 mortality during the second wave of the pandemic in Europe
Abstract
BACKGROUND
Preliminary clinical evidence suggests an increased COVID-19 mortality associated with the variant of concern 20I/501Y.V1. The evidence outside the UK and a real-world comparison of variants spread and mortality is sparse. This study aims at investigating the association between COVID-19 mortality and SARS-COV-2 variants spread during the second wave of the COVID-19 pandemic in Europe.
METHODS
For 38 European countries, publicly available data were collected on numbers of COVID-19 deaths, SARS-COV-2 variants spread through time using Nextstrain classification and countries’ demographic and health characteristics. The cumulative number of COVID-19 deaths and the height of COVID-19 daily deaths peak during the second wave of the pandemic were considered as outcomes. Pearson correlations and multivariate generalized linear models with selection algorithms were used.
FINDINGS
The average proportion of 20I/501Y.V1 variant (B.1.1.7) was found to be a significant predictor of cumulative number of COVID-19 deaths within two months before the deaths peak and between 1 January – 25 February 2021, as well as of the deaths’ peak height when calculating the proportion during the second wave and the pre-peak period. The average proportion of 20A.EU2 variant (S:477N) was a significant predictor of cumulative COVID-19 deaths in the pre-peak period.
INTERPRETATION
Our findings suggest that the spread of a new variant of concern 20I/501Y.V1 had a significant impact on the mortality during the second wave of COVID-19 pandemic in Europe and that proportions of 20A.EU2 and 20I/501Y.V1 variants were associated with increased mortality in the initial phase of that wave.
Research in context
Evidence before this study
Emerging evidence suggests that the new variant of concern 20I/501Y.V1 (B.1.1.7) may be associated with an increased risk of death. The 20A.EU2 variant (S:447N), observed firstly in July 2020 in western Europe, was found to be capable of increasing SARS-COV-2 infectivity. The evidence outside the UK is still sparse, same as a real-world comparison of distinct variants spread and mortality through time.
Added value of this study
In this study we investigated whether the change of the proportion of any SARS-COV-2 variant, including 20I/501Y.V1 and 11 other variants identified by Nextstrain up to 25 February 2021, has an association with COVID-19 cumulative mortality or with the height of the second wave COVID-19 mortality peak.
Implications of all the available evidence
Our findings shed light on the causes of the increased COVID-19 mortality during the second wave of the pandemic in Europe. It shows the need for early containment strategies when the variant 20I/501Y.V1 emerges. These findings also support the need for systematic SARS-CoV-2 regular genome sequencing to control the COVID-19 pandemic.
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