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. 2025 Jul 1;113(3):543-554.
doi: 10.4269/ajtmh.24-0826. Print 2025 Sep 3.

Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence and Coronavirus Disease 2019 Vaccination Trends: Findings from Surveillance Conducted at First Antenatal Care Visits in Kenya, Nigeria, Malawi, Mozambique, Uganda, and Zambia, 2021-2022

Victoria Seffren  1 , Ruchi Yadav  1 , Nnaemeka C Iriemenam  2 , Oluseye Ajayi  3 , Olabanjo Ogunsola  3 , Conceptor Mulube  4 , Felix Bwalya Chilambe  5 , Monica Soko  6 , Francis Ogollah  7 , Miriam Chomba  8 , Brian Seda  8 , Idalécia Cossa-Moiane  9 , Zainabo Langa  9 , Paul Oboth  10 , Richard Kwizera  10 , Eric Rogier  1 , Julie R Gutman  1
Affiliations

Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence and Coronavirus Disease 2019 Vaccination Trends: Findings from Surveillance Conducted at First Antenatal Care Visits in Kenya, Nigeria, Malawi, Mozambique, Uganda, and Zambia, 2021-2022

Victoria Seffren et al. Am J Trop Med Hyg. .

Abstract

Estimates of exposure to coronavirus disease 2019 (COVID-19) on the African continent are limited, constrained by availability of testing and case report data. To improve understanding of COVID-19 burden, monthly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveillance was implemented at first antenatal care visits (ANC1) across six sub-Saharan African countries (Kenya, Malawi, Mozambique, Nigeria, Uganda, and Zambia). A standardized questionnaire, including COVID-19 vaccination history, was administered, and a blood sample was collected. Serology was conducted with two assays: in Nigeria, a multiplex bead-based assay targetting spike protein, receptor binding domain (RBD) 591, and nucleocapsid (N) protein and in all other countries, a SARS-CoV-2 human IgG antibody test including RBD, N protein, and hybrid RBD-N. The largest monthly change in seropositivity was between December 2021 and January 2022 for five countries (Kenya: 33.2-70.3%, Malawi: 28.3-59.6%, Mozambique: 29.3-72.8%, Nigeria: 52.4-77.4%, Uganda: 55.7-80.6%), coinciding with the Omicron wave. Aside from Mozambique, there was an increase in the proportion of women reporting COVID-19 vaccination beginning in January 2022, with highest vaccination rates between April and August 2022. Relatedly, there was an increase in the proportion vaccinated among those with detectable SARS-CoV-2 antibodies. Adenoviral vector accounted for at least half of the vaccines reported in all countries. If pregnant women are not differentially infected, ANC1 can be leveraged for serosurveillance during a pandemic. Monthly seroprevalence estimates alongside vaccination rates can provide evidence for changes in protective immunity in response to case waves and the introduction of protective measures.

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Conflict of interest statement

Disclosures: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the U.S. Centers for Disease Control and Prevention. V. Seffren and J. R. Gutman accept full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.

Authors’ contributions: J. R. Gutman designed the work. B. Seda performed data collection and oversight for Kenya. O. Ajayi and O. Ogunsola performed data collection and oversight for Nigeria. P. Oboth performed data collection and oversight for Uganda. R. Yadav performed sample analysis. M. Chombe performed sample analysis for Kenya. M. Soko and F. Ogollah performed sample analysis for Malawi. I. Cossa-Moiane and Z. Langa performed sample analysis for Mozambique. N. C. Iriemenam performed sample analysis for Nigeria. R. Kwizera performed sample analysis for Uganda. C. Mulube and F. B. Chilambe performed sample analysis for Zambia. V. Seffren performed data analysis. V. Seffren, R. Yadav, E. Rogier, and J. R. Gutman interpreted the data. M. Chombe and B. Seda interpreted the Kenya data. M. Soko and F. Ogollah interpreted the Malawi data. I. Cossa-Moiane interpreted the Mozambique data. N. C. Iriemenam interpreted the Nigeria data. P. Oboth and R. Kwizera interpreted the Uganda data. C. Mulube and F. B. Chilambe interpreted the Zambia data. V. Seffren and J. R. Gutman drafted the article. All authors critically revised the article, reviewed the final version, and agreed to publication.

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