On Jun. 24, 2021, researchers from the University of Oxford released their findings about the so-called ﾑcorrelates of protectionﾒ against symptomatic COVID-19; potentially a tool to speed up safe development of new vaccines which may assist regulators in assessing the likely potency of any new COVID-19 vaccine without the need for Phase III efficacy trial data.

Writing on MedRxiv, they reported that higher levels of anti-spike, anti-RBD IgG, and neutralising antibody titres were associated with a greater degree of protection against COVID-19 ﾖ defined as a PCR positive test with at least one symptom present.