Higher mortality associated with the SARS-CoV-2 Delta variant in the Western Cape, South Africa, using RdRp target delay as a proxy

A novel proxy for the Delta variant, RNA-dependent RNA polymerase target delay in the Seegene Allplex 2019-nCoV PCR assay, was associated with higher mortality (adjusted Odds Ratio 1.45 [95%CI 1.13-1.86]), compared to presumptive Beta infection, in the Western Cape, South Africa (April-July 2021). Prior diagnosed infection and vaccination were protective.