TY - JOUR
T1 - Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold
AU - Gomes, M. Gabriela M.
AU - Ferreira, Marcelo Urbano
AU - Corder, Rodrigo M.
AU - King, Jessica G.
AU - Souto-Maior, Caetano
AU - Penha-Gonçalves, Carlos
AU - Gonçalves, Guilherme
AU - Chikina, Maria
AU - Pegden, Wesley
AU - Aguas, Ricardo
N1 - Funding Information:
We thank Jorge Carneiro, Ben Cooper, José Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalbán, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G., on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil.
Funding Information:
We thank Jorge Carneiro, Ben Cooper, Jos? Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalb?n, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G. on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, Brazil.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/5/7
Y1 - 2022/5/7
N2 - Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic.
AB - Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic.
KW - COVID-19
KW - Epidemic model
KW - Frailty variation
KW - Herd immunity threshold
KW - Individual variation
KW - Selection within cohorts
UR - http://www.scopus.com/inward/record.url?scp=85125527948&partnerID=8YFLogxK
U2 - 10.1016/j.jtbi.2022.111063
DO - 10.1016/j.jtbi.2022.111063
M3 - Article
C2 - 35189135
AN - SCOPUS:85125527948
SN - 0022-5193
VL - 540
SP - 1
EP - 20
JO - Journal Of Theoretical Biology
JF - Journal Of Theoretical Biology
M1 - 111063
ER -
