Related Experiment Video
Updated: Aug 13, 2025

Author Spotlight: Advancing Immune Monitoring in Critical Care Patients Using Whole Blood Assays
Published on: September 20, 2024
Immune correlates analysis of the PREVENT-19 COVID-19 vaccine efficacy clinical trial
Youyi Fong1,2, Yunda Huang1,3, David Benkeser4
1Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
Abstract:
In the PREVENT-19 phase 3 trial of the NVX-CoV2373 vaccine (NCT04611802), anti-spike binding IgG concentration (spike IgG), anti-RBD binding IgG concentration (RBD IgG), and pseudovirus 50% neutralizing antibody titer (nAb ID50) measured two weeks post-dose two are assessed as correlates of risk and as correlates of protection against COVID-19. Analyses are conducted in the U.S. cohort of baseline SARS-CoV-2 negative per-protocol participants using a case-cohort design that measures the markers from all 12 vaccine recipient breakthrough COVID-19 cases starting 7 days post antibody measurement and from 639 vaccine recipient non-cases. All markers are inversely associated with COVID-19 risk and directly associated with vaccine efficacy. In vaccine recipients with nAb ID50 titers of 50, 100, and 7230 international units (IU50)/ml, vaccine efficacy estimates are 75.7% (49.8%, 93.2%), 81.7% (66.3%, 93.2%), and 96.8% (88.3%, 99.3%). The results support potential cross-vaccine platform applications of these markers for guiding decisions about vaccine approval and use.
Related Concept Videos
Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
Clinical Trials
There are four phases in a clinical trial. A phase one...
Clinical Trials: Overview
Antimicrobial Effectiveness
Myocarditis II: Clinical Features and Diagnostic Tests
Bias in Epidemiological Studies

