Individual variation in vaccine immune response can produce bimodal distributions of protection

Cameron Zachreson; Ruarai Tobin; Joshua Szanyi; Camelia Walker; Deborah Cromer; Freya M Shearer; Eamon Conway; Gerard Ryan; Allen Cheng; James M McCaw; Nicholas Geard

doi:10.1016/j.vaccine.2023.09.025

Individual variation in vaccine immune response can produce bimodal distributions of protection

Vaccine. 2023 Oct 26;41(45):6630-6636. doi: 10.1016/j.vaccine.2023.09.025. Epub 2023 Oct 2.

Authors

Affiliations

¹ School of Computing and Information Systems, The University of Melbourne, Parkville, Victoria, Australia. Electronic address: cameron.zachreson@unimelb.edu.au.
² Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia.
³ School of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria, Australia.
⁴ Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia.
⁵ Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia; Telethon Kids Institute, Nedlands, Western Australia, Australia.
⁶ The Walter and Eliza Hall Institute, Melbourne, Victoria, Australia.
⁷ Monash Infectious Diseases, Monash Health and School of Clinical Sciences, Monash University, Clayton, Victoria, Australia.
⁸ Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia; School of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria, Australia.
⁹ School of Computing and Information Systems, The University of Melbourne, Parkville, Victoria, Australia.

PMID: 37793975
DOI: 10.1016/j.vaccine.2023.09.025

Abstract

The ability for vaccines to protect against infectious diseases varies among individuals, but computational models employed to inform policy typically do not account for this variation. Here we examine this issue: we implement a model of vaccine efficacy developed in the context of SARS-CoV-2 in order to evaluate the general implications of modelling correlates of protection on the individual level. Due to high levels of variation in immune response, the distributions of individual-level protection emerging from this model tend to be highly dispersed, and are often bimodal. We describe the specification of the model, provide an intuitive parameterisation, and comment on its general robustness. We show that the model can be viewed as an intermediate between the typical approaches that consider the mode of vaccine action to be either "all-or-nothing" or "leaky". Our view based on this analysis is that individual variation in correlates of protection is an important consideration that may be crucial to designing and implementing models for estimating population-level impacts of vaccination programs.

Keywords: Correlates of protection; Immunogenicity; Leaky vaccines; Models of vaccine efficacy; Vaccine efficacy; Waning immunity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19* / prevention & control
Communicable Diseases*
Humans
Immunity
SARS-CoV-2
Vaccines*

Substances

Vaccines