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Volume 29, Number 2—February 2023

Correlates of Protection, Thresholds of Protection, and Immunobridging among Persons with SARS-CoV-2 Infection

David S. KhouryComments to Author , Timothy E. Schlub, Deborah Cromer, Megan Steain, Youyi Fong, Peter B. Gilbert, Kanta Subbarao, James A. Triccas, Stephen J. Kent, and Miles P. DavenportComments to Author 
Author affiliations: The University of New South Wales, Sydney, New South Wales, Australia (D.S. Khoury, D. Cromer, M.P. Davenport); University of Sydney, Sydney (T.E. Schlub, M. Steain, J.A. Triccas); Fred Hutchinson Cancer Research Center, Seattle, Washington, USA (Y. Fong, P.B. Gilbert); The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia (K. Subbarao, S.J. Kent); Monash University, Melbourne (S.J. Kent)

Main Article


Glossary of terms used in study of correlates of protection for SARS-CoV-2 infection

Term Definition
Protection curve
The relationship between the measured immune response of a vaccine in a subgroup of persons and the level of protection from symptomatic infection provided by the vaccine in that subgroup compared with placebo group (protection = vaccine efficacy).
Threshold of protection
The level of immune response required to provide a specified level of protection (vaccine efficacy) from COVID-19. The 50% protective threshold is commonly reported.
Fold-of-convalescent scale
An attempt to compare different assays by normalizing titers to that of convalescing persons in the same assay. Accurate comparison requires convalescing persons to have similar infection histories.
IU/mL A neutralization titer (or mean neutralization titer) calibrated to a World Health Organization international standard and reported in IU/mL.

Main Article

Page created: December 20, 2022
Page updated: January 21, 2023
Page reviewed: January 21, 2023
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