http://www.sciencemag.org/news/2021/07/can-immune-responses-alone-reveal-which-covid-19-vaccines-work-best

An antibody (red/pink) latches on to the surface protein of SARS-CoV-2 (green). Many scientists believe the level of so-called neutralizing antibodies triggered by a vaccine predicts how well it protects.

Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.