High SARS-CoV-2 incidence and asymptomatic fraction during Delta and Omicron BA.1 waves in The Gambia

Abstract

Little is known about SARS-CoV-2 infection risk in African countries with high levels of infection-driven immunity and low vaccine coverage. We conducted a prospective cohort study of 349 participants from 52 households in The Gambia between March 2021 and June 2022, with routine weekly SARS-CoV-2 RT-PCR and 6-monthly SARS-CoV-2 serology. Attack rates of 45% and 57% were seen during Delta and Omicron BA.1 waves respectively. Eighty-four percent of RT-PCR-positive infections were asymptomatic. Children under 5-years had a lower incidence of infection than 18-49-year-olds. One prior SARS-CoV-2 infection reduced infection risk during the Delta wave only, with immunity from ≥2 prior infections required to reduce the risk of infection with early Omicron lineage viruses. In an African population with high levels of infection-driven immunity and low vaccine coverage, we find high attack rates during SARS-CoV-2 waves, with a high proportion of asymptomatic infections and young children remaining relatively protected from infection.

Metadata

Item Type:	Article
Authors/Creators:	Jarju, S. Wenlock, R.D. https://orcid.org/0000-0001-7510-0821 Danso, M. Jobe, D. Jagne, Y.J. Darboe, A. Kumado, M. Jallow, Y. Touray, M. Ceesay, E.A. Gaye, H. Gaye, B. Tunkara, A. Kandeh, S. Gomes, M. Sylva, E.L. Toure, F. Hornsby, H. https://orcid.org/0000-0002-6657-9743 Lindsey, B.B. https://orcid.org/0000-0003-4227-2592 Nicklin, M.J. Sayers, J.R. https://orcid.org/0000-0002-5082-1443 Sesay, A.K. Kucharski, A. Hodgson, D. https://orcid.org/0000-0002-5585-8974 Kampmann, B. de Silva, T.I. https://orcid.org/0000-0002-6498-9212
Copyright, Publisher and Additional Information:	© The Author(s) 2024. Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Keywords:	Humans; Gambia; COVID-19; Incidence; SARS-CoV-2; Female; Child, Preschool; Male; Adolescent; Child; Adult; Asymptomatic Infections; Prospective Studies; Middle Aged; Young Adult; Infant; Epidemiology; Risk factors; SARS-CoV-2
Dates:	Published: 7 May 2024 Published (online): 7 May 2024 Accepted: 19 April 2024 Submitted: 6 January 2024
Institution:	The University of Sheffield
Academic Units:	The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Medicine and Population Health The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > Department of Infection, Immunity and Cardiovascular Disease
Depositing User:	Symplectic Sheffield
Date Deposited:	14 May 2024 14:11
Last Modified:	14 May 2024 14:11
Status:	Published
Publisher:	Springer Science and Business Media LLC
Refereed:	Yes
Identification Number:	10.1038/s41467-024-48098-3
Related URLs:	PubMed URL Dataset
Sustainable Development Goals:
Open Archives Initiative ID (OAI ID):	oai:eprints.whiterose.ac.uk:212473