Effectiveness of COVID-19 vaccines against SARS CoV-2 infection with the Delta (B.1.617.2) variant: second interim results of a living systematic review and meta-analysis, 1 January to 25 August 2021

Abstract

The Delta variant (Phylogenetic Assignment of Named Global Outbreak (Pango) lineage designation B.1.617.2) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in October 2020 and has spread to more than 180 countries globally [1]. Concerns were raised about how well the currently available vaccines protect against this variant. Since January 2021, the Robert Koch Institute (RKI), in collaboration with the National Immunisation Technical Advisory Groups (NITAGs) network coordinated by the European Centre for Disease Prevention and Control (ECDC) is performing a living systematic review on the efficacy, effectiveness and safety of coronavirus disease (COVID-19) vaccines authorised in the European Union (EU) (PROSPERO registration: CRD42020208935) [2]. Here we present results on the effectiveness and the duration of protection provided by the EU-licensed COVID-19 vaccines in respect to the Delta variant.