SARS-CoV-2 seroprevalence at urban and rural sites in Kaduna State, Nigeria, during October/November 2021, immediately prior to detection of the Omicron variant

Chechet, G. D., Kwaga, J. K.P., Yahaya, J., Noyes, H., MacLeod, A. and Adamson, W. E. (2022) SARS-CoV-2 seroprevalence at urban and rural sites in Kaduna State, Nigeria, during October/November 2021, immediately prior to detection of the Omicron variant. International Journal of Epidemiology, 51(5), pp. 1361-1370. (doi: 10.1093/ije/dyac141) (PMID:35771662) (PMCID:PMC9278217)

Abstract

Background: Nigeria is Africa’s most populated country. By November 2021 it had experienced three waves of SARS-CoV-2 infection. Peer-reviewed seroprevalence data assessing the proportion of the Nigerian population that have been infected were extremely limited. Methods: We conducted a serosurvey in one urban site (n = 400) and one rural site (n = 402) in Kaduna State, Nigeria between 11 October 2021 and 8 November 2021. Z-tests were used to compare seroprevalence across age groups, locations and sexes. T tests were used to determine whether age or household size are associated with seropositivity. Associations between seropositivity and recent history of common Covid-19 symptoms were tested using logistic regression. Results: SARS-CoV-2 antibodies were detected in 42.5% an 53.5% of participants at the urban and rural sites, respectively The overall age- and sex- stratified seroprevalence was 43.7% (42.2% for unvaccinated individuals). The data indicate an infection rate in Kaduna State ≥359-fold the rate derived from polymerase chain reaction-confirmed cases. In the urban site, seroprevalence among females and participants aged <20 was lower than other groups. Reporting loss of sense of taste and/or smell was strongly associated with seropositive status. Associations with seropositivity were also found for the reporting of dry cough, fever, headache, nausea and sore throat. Conclusions: This study provides baseline SARS-CoV-2 seroprevalence in Kaduna State, Nigeria, immediately prior to the spread of the Omicron variant. It indicates that in October/November 2021, approximately 56% of the population did not have detectable antibodies, and population subgroups with particularly low seroprevalence remain. It highlights limitations in using PCR-confirmed cases to estimate infection rates. The data will inform public health strategies in Nigeria and other sub-Saharan African countries with limited SARS-CoV-2 seroprevalence data.

• Item Type: Articles
• Additional Information: Funding: This work was funded by the University of Glasgow COVID-19 Researcher Support Scheme.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Adamson, Dr Walt and MacLeod, Professor Annette
• Authors: Chechet, G. D., Kwaga, J. K.P., Yahaya, J., Noyes, H., MacLeod, A., and Adamson, W. E.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: International Journal of Epidemiology
• Publisher: Oxford University Press
• ISSN: 0300-5771
• ISSN (Online): 1464-3685
• Published Online: 28 June 2022
• Copyright Holders: Copyright © 2022 The Author(s)
• First Published: First published in International Journal of Epidemiology 51(5): 1361-1370
• Publisher Policy: Reproduced under a Creative Commons licence