Conference Abstract | Volume 8, Abstract ELIC2025406 (Poster 039) | Published: 31 Jul 2025
Ephraim Ogbaini-Emovon1,&, Mambu Momoh2, John Sandi2, Rita Esumeh1, Thomas Olokor1, Ighodalo Yemisi1, Rachael Omiunu1, Oluwasola Babatunde1, A. Goba2, Deborah Ehichioya1, Fritz Fonkeng3, G. Ngoma4, Michael Ramharter5, Sylvanus Okogbenin1, Cyril Erameh1, Mojeed Rafiu1, Joseph Okoguale1, Reuben Eifediyi1, George Akpede1, Nelson Adedosu6, Chiedozie Ojide7, Robert Garry8, Stephan Guenther9, Daniel Bausch10,11, Aurelia Vessiere12, Jilian Sacks12, Devy Emperador13, Donald Grant2, Hanesh Fru Chi1
1Irrua Specialist Teaching Hospital, Irrua, Nigeria, 2Kenema Government Hospital, Kenema, Sierra Leone, 3FIND, Geneva, Switzerland, 44Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon, 5University Medical Center Hamburg-Eppendorf German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, 6Federal Medical Centre Owo, Owo, Nigeria, 7Federal Teaching Hospital Abakaliki, Abakaliki, Nigeria, 8Tulane University, New Orleans, United States, 9Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & Hygiene, 10London School of Hygiene and Tropical Medicine, United Kingdom, 11National University of Singapore, Singapore, 12Roche Diagnostics, Geneva, Switzerland, 13World Health Organization, Geneva, Switzerland
&Corresponding author: Ephraim Ogbaini-Emovon, Irrua Specialist Teaching Hospital, Irrua, Nigeria, Email: epogbaini@yahoo.com
Received: 25 May 2025, Accepted: 09 Jun 2025, Published: 31 Jul 2025
Domain: Infectious Disease Epidemiology, Vaccinology
Keywords: Lassa fever, Immunoglobulin G, Serologic assays, Sensitivity and specificity
©Ephraim Ogbaini-Emovon et al Journal of Interventional Epidemiology and Public Health (ISSN: 2664-2824). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cite this article: Ephraim Ogbaini-Emovon et al., Comparative evaluation of five Lassa virus IgG immunoassays for seroprevalence studies and vaccine trial support in West Africa. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00183. https://doi.org/10.37432/JIEPH-CONFPRO5-00183
Serological testing is pivotal in diagnosing Lassa fever and conducting sero-epidemiological studies essential for planning vaccine efficacy trials in endemic regions. However, comparative data on the performance of available Lassa virus (LASV) serologic assays remain limited. To support clinical trials in West Africa, we conducted a comparative evaluation of five LASV-specific IgG immunoassays to determine their diagnostic utility.
This diagnostic evaluation study was performed at the Irrua Specialist Teaching Hospital, Nigeria, and Kenema Government Hospital, Sierra Leone. A total of 148 archived LASV-RT-PCR-positive sera from Nigeria and 158 LASV-antigen-positive sera from Sierra Leone were tested. LASV-naïve sera from Gabon served as negative controls. The U.S. CDC LASV IgG assay was used as the reference test. Positive percentage agreement (PPA) and negative percentage agreement (NPA) were calculated against either the reference assay or the expected clinical classification based on historical data and sample origin. Country-specific performance metrics were computed for LASV-exposed and LASV-naïve samples.
Among LASV-positive cases by clinical category, 123/158 (Sierra Leone) and 104/148 (Nigeria) were IgG-positive using the reference assay. Four of the five evaluated immunoassays demonstrated PPA ≥90% compared to the reference. Two assays exhibited NPA ≥95% in both countries. Country-level findings aligned with combined analyses, with slightly improved NPA among LASV-naïve versus LASV-exposed but seronegative individuals.
Menu