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The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants

INTRODUCTION: A key feature of the COVID-19 pandemic has been the emergence of SARS-CoV-2 variants with different transmission characteristics. However, when a novel variant arrives in a host population, it will not necessarily lead to many cases. Instead, it may fade out, due to stochastic effects...

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Autores principales: Thompson, Robin N., Southall, Emma, Daon, Yair, Lovell-Read, Francesca A., Iwami, Shingo, Thompson, Craig P., Obolski, Uri
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874934/
https://www.ncbi.nlm.nih.gov/pubmed/36713397
http://dx.doi.org/10.3389/fimmu.2022.1049458
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author Thompson, Robin N.
Southall, Emma
Daon, Yair
Lovell-Read, Francesca A.
Iwami, Shingo
Thompson, Craig P.
Obolski, Uri
author_facet Thompson, Robin N.
Southall, Emma
Daon, Yair
Lovell-Read, Francesca A.
Iwami, Shingo
Thompson, Craig P.
Obolski, Uri
author_sort Thompson, Robin N.
collection PubMed
description INTRODUCTION: A key feature of the COVID-19 pandemic has been the emergence of SARS-CoV-2 variants with different transmission characteristics. However, when a novel variant arrives in a host population, it will not necessarily lead to many cases. Instead, it may fade out, due to stochastic effects and the level of immunity in the population. Immunity against novel SARS-CoV-2 variants may be influenced by prior exposures to related viruses, such as other SARS-CoV-2 variants and seasonal coronaviruses, and the level of cross-reactive immunity conferred by those exposures. METHODS: Here, we investigate the impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants in a simplified scenario in which a novel SARS-CoV-2 variant is introduced after an antigenically related virus has spread in the population. We use mathematical modelling to explore the risk that the novel variant invades the population and causes a large number of cases, as opposed to fading out with few cases. RESULTS: We find that, if cross-reactive immunity is complete (i.e. someone infected by the previously circulating virus is not susceptible to the novel variant), the novel variant must be more transmissible than the previous virus to invade the population. However, in a more realistic scenario in which cross-reactive immunity is partial, we show that it is possible for novel variants to invade, even if they are less transmissible than previously circulating viruses. This is because partial cross-reactive immunity effectively increases the pool of susceptible hosts that are available to the novel variant compared to complete cross-reactive immunity. Furthermore, if previous infection with the antigenically related virus assists the establishment of infection with the novel variant, as has been proposed following some experimental studies, then even variants with very limited transmissibility are able to invade the host population. DISCUSSION: Our results highlight that fast assessment of the level of cross-reactive immunity conferred by related viruses against novel SARS-CoV-2 variants is an essential component of novel variant risk assessments.
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spelling pubmed-98749342023-01-26 The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants Thompson, Robin N. Southall, Emma Daon, Yair Lovell-Read, Francesca A. Iwami, Shingo Thompson, Craig P. Obolski, Uri Front Immunol Immunology INTRODUCTION: A key feature of the COVID-19 pandemic has been the emergence of SARS-CoV-2 variants with different transmission characteristics. However, when a novel variant arrives in a host population, it will not necessarily lead to many cases. Instead, it may fade out, due to stochastic effects and the level of immunity in the population. Immunity against novel SARS-CoV-2 variants may be influenced by prior exposures to related viruses, such as other SARS-CoV-2 variants and seasonal coronaviruses, and the level of cross-reactive immunity conferred by those exposures. METHODS: Here, we investigate the impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants in a simplified scenario in which a novel SARS-CoV-2 variant is introduced after an antigenically related virus has spread in the population. We use mathematical modelling to explore the risk that the novel variant invades the population and causes a large number of cases, as opposed to fading out with few cases. RESULTS: We find that, if cross-reactive immunity is complete (i.e. someone infected by the previously circulating virus is not susceptible to the novel variant), the novel variant must be more transmissible than the previous virus to invade the population. However, in a more realistic scenario in which cross-reactive immunity is partial, we show that it is possible for novel variants to invade, even if they are less transmissible than previously circulating viruses. This is because partial cross-reactive immunity effectively increases the pool of susceptible hosts that are available to the novel variant compared to complete cross-reactive immunity. Furthermore, if previous infection with the antigenically related virus assists the establishment of infection with the novel variant, as has been proposed following some experimental studies, then even variants with very limited transmissibility are able to invade the host population. DISCUSSION: Our results highlight that fast assessment of the level of cross-reactive immunity conferred by related viruses against novel SARS-CoV-2 variants is an essential component of novel variant risk assessments. Frontiers Media S.A. 2023-01-11 /pmc/articles/PMC9874934/ /pubmed/36713397 http://dx.doi.org/10.3389/fimmu.2022.1049458 Text en Copyright © 2023 Thompson, Southall, Daon, Lovell-Read, Iwami, Thompson and Obolski https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Immunology
Thompson, Robin N.
Southall, Emma
Daon, Yair
Lovell-Read, Francesca A.
Iwami, Shingo
Thompson, Craig P.
Obolski, Uri
The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title_full The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title_fullStr The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title_full_unstemmed The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title_short The impact of cross-reactive immunity on the emergence of SARS-CoV-2 variants
title_sort impact of cross-reactive immunity on the emergence of sars-cov-2 variants
topic Immunology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874934/
https://www.ncbi.nlm.nih.gov/pubmed/36713397
http://dx.doi.org/10.3389/fimmu.2022.1049458
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