Viral replication dynamics could critically modulate vaccine effectiveness and should be accounted for when assessing new SARS-CoV-2 variants

TL;DR

This paper introduces a theory emphasizing the importance of viral replication dynamics in understanding vaccine effectiveness against SARS-CoV-2 variants, suggesting current lab measures are insufficient.

Contribution

It proposes a new model incorporating in-host viral replication dynamics to better evaluate the impact of variants on vaccine effectiveness.

Findings

Viral replication dynamics influence vaccine effectiveness.

Current neutralization tests may underestimate variant impact.

A new assessment approach could improve public health responses.

Abstract

In this article, we propose a theory to explain the reduction in vaccine effectiveness (VE) against the Delta SARS-CoV-2 variant and decreasing VE over time reported in recent studies. Using a model illustration, we show that in-host viral replication dynamics and delays in immune response could play a key role in VE. Given this, current laboratory approaches solely measuring reductions in neutralizing ability cannot fully represent the potential impact of new SARS-CoV-2 variants. We instead propose an alternative approach that incorporates viral replication dynamics into evaluations of SARS-CoV-2 variant impact on immunity and VE. This more robust assessment may better inform public health response to new variants like the newly detected Omicron variant.