Conference Abstract | Volume 8, Abstract ELIC2025293 (Oral 097) | Published: 14 Aug 2025
Danny Akhere Asogun1,2,&, Sylvanus Akhalufo Okogbenin1,3, Anton Camacho4, Henshaw Mandi5, Ekaete Alice Tobin1,2, George Akpede1,6
1Institute of Viral and Emergent Pathogens Control and Research, Irrua Specialist Teaching Hospital, Irrua, Nigeria, 2Department of Community Medicine, Ambrose Alli University, Ekpoma, Nigeria, 3Department of Obstetrics & Gynaecology, Ambrose Alli University, Ekpoma, Nigeria, 4EPICENTRE, Paris, France, 5Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway6Department of Paediatrics, Ambrose Alli University, Ekpoma, Nigeria
&Corresponding author: Danny Akhere Asogun, .Institute of Viral and Emergent pathogens Control and Research, Irrua Specialist Teaching Hospital, Irrua, Nigeria, Email: dannyasogun@aauekpoma.edu.ng
Received: 31 May 2025, Accepted: 09 Jul 2025, Published: 14 Aug 2025
Domain: Infectious Disease Epidemiology
Keywords: Lassa fever incidence, disease burden, active surveillance, RT-PCR
©Danny Akhere Asogun 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: Danny Akhere Asogun et al., Incidence of symptomatic Lassa fever infection in endemic communities: Results from the ENABLE 1.0 prospective cohort in Edo State, Nigeria. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00097. https://doi.org/10.37432/JIEPH-CONFPRO5-00097
Lassa fever (LF), a viral zoonotic disease endemic to West Africa, often causes no or mild, non-specific symptoms, but severe cases can result in haemorrhage, multi-organ failure, and death. Its burden remains poorly defined, yet, is essential for guiding vaccine trials. Here, we report on symptomatic LF incidence in a Nigerian site of the Enable Lassa research programme.
A prospective community-based longitudinal cohort enrolled participants ≥2 years old in Edo State, Nigeria, from 2020. Participants were followed up for 30 months and monitored for acute febrile illness through active/passive surveillance. Participants meeting the acute febrile case definition were tested for LF by RT-PCR using acute blood samples. LF positive cases were hospitalised with hearing assessed at discharge and four months post-discharge to determine sensorineural hearing loss (SNHL).
Of 5,025 participants recruited, 3,543 suspected LF cases were assessed, with 23 confirmed by RT-PCR, yielding an overall incidence of 1.90 (95%CI 1.20–2.85) per 1,000 person-years. Symptoms included headache (91%), abdominal pain (83%), muscle/joint pain (57%) and vomiting (35%). Two cases were fatal (CFR 9%). Nine of 21 (43%) LF cases with hearing tests performed had SNHL at discharge, increasing to 13 at four months follow up.
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