Nigeria healthcare worker SARS-CoV-2 serology study: Results from a prospective, longitudinal cohort

Dike B Ojji; Amelia Sancilio; Gabriel L Shedul; Ikechukwu A Orji; Aashima Chopra; Joel Abu; Blessing Akor; Nana Ripiye; Funmi Akinlade; Douglas Okoye; Emmanuel Okpetu; Helen Eze; Emmanuel Odoh; Abigail S Baldridge; Priya Tripathi; Haruna Abubakar; Abubakar M Jamda; Lisa R Hirschhorn; Thomas McDade; Mark D Huffman

doi:10.1371/journal.pgph.0000549

Nigeria healthcare worker SARS-CoV-2 serology study: Results from a prospective, longitudinal cohort

PLOS Glob Public Health. 2023 Jan 17;3(1):e0000549. doi: 10.1371/journal.pgph.0000549. eCollection 2023.

Authors

Dike B Ojji^{1

2}, Amelia Sancilio³, Gabriel L Shedul¹, Ikechukwu A Orji¹, Aashima Chopra⁴, Joel Abu¹, Blessing Akor¹, Nana Ripiye¹, Funmi Akinlade⁵, Douglas Okoye¹, Emmanuel Okpetu¹, Helen Eze¹, Emmanuel Odoh⁶, Abigail S Baldridge^{4

7}, Priya Tripathi⁴, Haruna Abubakar², Abubakar M Jamda⁸, Lisa R Hirschhorn⁹, Thomas McDade³, Mark D Huffman^{4

10

11}

Affiliations

¹ Department of Internal Medicine, Faculty of Clinical Sciences, Federal Capital Territory, University of Abuja, Abuja, Nigeria.
² Cardiovascular Research Unit, University of Abuja and University of Abuja Teaching Hospital, Federal Capital Territory, Abuja, Nigeria.
³ Northwestern University Department of Anthropology and Institute for Policy Research, Evanston, Illinois, United States of America.
⁴ Northwestern University Department of Preventive Medicine, Chicago, Illinois, United States of America.
⁵ Johns Hopkins University, Baltimore, Maryland, United States of America.
⁶ Abaji Department of Primary Care, Abaji, Federal Capital Territory, Abuja, Nigeria.
⁷ Bluhm Cardiovascular Institute Clinical Trials Unit, Northwestern Medicine, Chicago, Illinois, United States of America.
⁸ Department of Community Medicine, Faculty of Clinical Sciences, Federal Capital Territory, University of Abuja, Abuja, Nigeria.
⁹ Northwestern University Department of Medical Social Sciences, Chicago, Illinois, United States of America.
¹⁰ Northwestern University Department of Medicine, Chicago, Illinois, United States of America.
¹¹ The George Institute for Global Health, University of New South Wales, Sydney, Australia.

Abstract

Healthcare workers, both globally and in Nigeria, have an increased risk for SARS-CoV-2 infection compared with the general population due to higher risk contacts, including occupational exposures. In addition, primary healthcare workers represent an important group for estimating prior infection to SARS-CoV-2 because they work at the first point-of-contact for most patients yet have not been included in prior COVID-19 seroepidemiology research in Nigeria. We sought to evaluate baseline seroprevalence, rates of seroconversion (IgG- to IgG+) and seroreversion (IgG+ to IgG-), change in IgG concentration at 3- and 6-month follow-up, and factors associated with seropositivity. From June 2020 to December 2020, we conducted a longitudinal seroepidemiology study among frontline health care workers in Nigeria using a validated dried blood spot assay. Among 525 participants, mean (SD) age was 39.1 (9.7) years, 61.0% were female, and 45.1% were community health workers. The six-month follow-up rate was 93.5%. Seropositivity rates increased from 31% (95% CI: 27%, 35%) at baseline to 45% (95% CI: 40%, 49%) at 3-month follow-up, and 70% (95% CI: 66%, 74%) at 6-month follow-up. There was a corresponding increase in IgG levels from baseline (median = 0.18 ug/mL) to 3-month (median = 0.35 ug/mL) and 6-month follow-up (median = 0.59 ug/mL, Ptrend < .0001). A minority of participants reported symptoms from February 2020 until baseline (12.2%) or during 3-month (6.6%) or 6-month (7.5%) follow-up. only 1 participant was hospitalized. This study demonstrated high baseline, 3-month and 6-month follow-up prevalence of IgG antibodies to SARS-CoV-2 during the first two waves of the COVID-19 pandemic in Nigeria among a cohort of unvaccinated frontline healthcare workers, including primary healthcare workers despite low symptomatology. These results may have implications in state- and national-level disease pandemic modeling. Trial registration: NCT04158154.

Copyright: © 2023 Ojji et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Associated data

ClinicalTrials.gov/NCT04158154

Grants and funding

This study was sponsored by the National Heart, Lung, and Blood Institute (R01HL144708) with additional support from the Robert J Havey MD Institute for Global Health and Northwestern University Clinical and Translational Science Institute (UL1TR00422). The funders had no role in the design, conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication.