To the Editor—To swiftly evaluate new therapies for a potential severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, reliable surrogate endpoints are essential. Based on an analysis of trial-level data, we previously found that nasopharyngeal viral load reduction reliably predicts a reduction in the risk of hospitalization or death across trials testing new SARS-CoV-2 therapies [1]. In a recent study, Giganti et al evaluated this relationship at the individual patient level.
