Conference Abstract | Volume 8, Abstract ELIC2025157 (Oral 0143) | Published:  11 Aug 2025

Enable 1.5: Implementing lessons learned from the Enable 1.0 study

Suzanne Penfold1, Dory Kovacs2, Henshaw Mandi2

1P95 Epidemiology and Pharmacovigilance, Leuven, Belgium, 2Coalition for Epidemic Preparedness Innovations (CEPI), Washington, D.C., United States

&Corresponding author: Suzanne Penfold, P95, Email: suzanne.penfold@p-95.com

Received: 31 May 2021, Accepted: 09 Jul 2025, Published: 11 Aug 2025

Domain: Infectious Disease Epidemiology

This is part of the Proceedings of the ECOWAS 2nd Lassa fever International Conference in Abidjan, September 8 – 11, 2025

Keywords: Clinical trials, Enable

©Suzanne Penfold 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: Suzanne Penfold et al., Enable 1.5: Implementing lessons learned from the Enable 1.0 study. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00143. https://doi.org/10.37432/JIEPH-CONFPRO5-00143

Introduction

Enable 1.0 was the largest Lassa Fever (LF) cohort study, estimating the incidence of Lassa virus (LASV) infection and LF disease. Here, we report Enable 1.0’s successes and challenges, and how these translate to Enable 1.5. Enable 1.0 fieldwork ran from 2020–2023 in Nigeria, Sierra Leone, Liberia, Benin, and Guinea, involving 27,000 participants followed for approximately two years. Disease cohort participants ≥2 years were followed up biweekly through in person or telephone consultations.

Methods

Suspected cases had fever present or reported in the preceding fortnight plus other symptom(s) indicative of LF and underwent testing by RT-PCR. LF cases were hospitalised, and medical record information extracted. Hearing assessment at discharge and four months later determined sensorineural hearing loss (SNHL).

Results

Blood samples were taken six monthly from a subset of participants (Infection cohort) to test LASV IgG status. Enable 1.0 identified 39 LF cases. Following community feedback, Enable 1.5 includes all ages to also determine LF burden in young children. As in-person follow up in Enable 1.0 resulted in better rapport and reporting, all follow up will be in person in Enable 1.5, allowing simultaneous clinical assessment. Case definition no longer hinges on fever, aiming to increase the number of suspected cases. As data extraction from medical records for Enable 1.0 was insufficient to analyse LF disease course, Enable 1.5 will actively collect patient data during treatment. Enable 1.0 identified LF cases with SNHL, but preexisting hearing loss was undocumented; Enable 1.5 is measuring hearing status at baseline. Enable 1.5 will conduct qualitative research to determine community understanding of LF and vaccine acceptability. Enable 1.5’s one year follow up includes quarterly blood draws for LASV IgG testing.

Conclusion

Enable 1.0 informed Enable 1.5 design, which began in November 2024. Enable 1.0 and 1.5 results will inform future LASV vaccine trial design.

 

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Keywords

  • Clinical trials
  • Enable
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