Systematic Review on Lassa Fever Vaccine Development Efforts in Africa – 2000 to 2024

Malgwi, Arhyel; Okoro, Onyebuchi; Tarfa, Moses; Dambazau, Zainab; Nnam, Nsikak; Abioye, Yetunde

doi:10.5281/zenodo.23543427

Presented at ECOWAS Lassa Fever International Conference 2025, Abidjan, 22–26 September 2025 · All posters from this congress

General Medicine Open accessPoster communication · 2026-0039

Systematic Review on Lassa Fever Vaccine Development Efforts in Africa – 2000 to 2024

Arhyel Malgwi¹^✉ORCID, Onyebuchi Okoro², Moses Tarfa², Zainab Dambazau^3,4, Nsikak Nnam^3,4, Yetunde Abioye⁵

¹ Nigeria Field Epidemiology and Laboratory Training Program
² 1. Nigeria Field Epidemiology and Laboratory Training Program
³ 1. Nigeria Field Epidemiology and Laboratory Training Program
⁴ 2. Nigeria Centre for Disease Control and Prevention
⁵ 1. Nigeria Centre for Disease Control and Prevention

Received 21 October 2026 · Accepted 21 October 2026 · Published 21 October 2026

DOI: https://doi.org/10.5281/zenodo.23543427

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Key messages

Despite decades of outbreaks, no licensed vaccine exists.
African involvement is growing, with Nigeria, Sierra Leone, and Liberia engaged in clinical research.
While Lassa vaccine development is progressing, substantial gaps in infrastructure, funding, and community engagement continue to hinder scale-up in Africa.

Abstract

Introduction

Lassa fever, an acute viral haemorrhagic illness endemic to West Africa, poses a persistent public health threat, with an estimated 100,000 to 300,000 infections and up to 5,000 deaths annually. Transmission occurs primarily through contact with excreta of Mastomys rats and secondary human to human spread, particularly in healthcare settings. Despite decades of outbreaks, no licensed vaccine exists. The World Health Organization classifies Lassa fever as a priority disease, underscoring the urgent need for effective vaccination strategies. This review evaluates the current landscape of Lassa fever vaccine development within the African context, examining progress, challenges, and opportunities for future interventions.

Materials and methods

A systematic review was conducted using databases such as PubMed, Scopus, Web of Science, WHO Clinical Trials Registry, and African Journals Online, focusing on literature from 2000 to 2024. Inclusion criteria comprised studies on Lassa vaccine candidates under preclinical or clinical development involving African institutions or populations. The PRISMA framework guided data extraction and descriptive analysis.

Results

Seventeen Lassa vaccine candidates were identified across various platforms, including viral vectors, mRNA, DNA, and live attenuated vaccines. Four candidates have entered early-stage human trials, notably INO-4500 and rVSV∆G-LASV-GPC. African involvement is growing, with Nigeria, Sierra Leone, and Liberia engaged in clinical research. However, challenges persist: weak regulatory frameworks, dependency on external funding, limited cold chain infrastructure, and cultural barriers to vaccine acceptance. Nonetheless, increased global partnerships and ethical trial practices reflect positive momentum.

Conclusion

While Lassa vaccine development is progressing, substantial gaps in infrastructure, funding, and community engagement continue to hinder scale-up in Africa. Sustained investment in African-led research, regulatory strengthening, and strategic partnerships are vital. Positioning African populations at the centre of vaccine efforts will ensure equity, efficacy, and long-term sustainability in combating Lassa fever.

Original poster

References

1. Richmond JK, Baglole DJ. Lassa fever: epidemiology, clinical features, and social consequences. BMJ. 2003;327(7426):1271–5.
2. McCormick JB, Fisher-Hoch SP. Lassa fever. Curr Top Microbiol Immunol. 2002;262:75–109.
3. WHO. Lassa Fever – Nigeria. World Health Organization Disease Outbreak News; 2023. Available from: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON429
4. World Health Organization. An R&D Blueprint for Action to Prevent Epidemics: Plan of Action. Geneva: WHO; 2016.
5. Henao-Restrepo AM, Camacho A, Longini IM, et al. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease. Lancet. 2017;389(10068):505–18.
6. Tinto H, Ouoba T, et al. Challenges and opportunities for African-led vaccine research and development. Lancet Glob Health. 2022;10(3):e343–4.
7. Ayoub Ettaqui, Safiya Echcherif El Kettani, Meryem Chennaq et al. Human leishmaniasis in Morocco: a systematic review and meta-analysis — I. Species distribution, 22 September 2026, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-11085884/v1]
8. Ajayi NA, Ukwaja KN, et al. Challenges in conducting Lassa fever vaccine trials in Africa. J Infect Dev Ctries. 2021;15(1):1–5.
9. CEPI. Lassa fever vaccine programs. Coalition for Epidemic Preparedness Innovations; 2024. Available from: https://cepi.net/research_dev/vaccine-development/lassa-fever
10. Nigeria Centre for Disease Control. Lassa Fever Situation Report. Abuja: NCDC; 2023.
11. Adepoju P. Regulatory and logistical challenges for Lassa fever vaccine deployment. Nat Med. 2020;26(7):981.
12. AVAREF. African Vaccine Regulatory Forum Progress Report. WHO-AFRO; 2022.
13. Ogbu O, Ajuluchukwu E, Uneke CJ. Lassa fever in West African sub-region: an overview. J Vector Borne Dis. 2007;44(1):1–11.
14. WHO-AFRO. Roadmap for Lassa Fever Vaccine Development and Deployment in Africa. Brazzaville: World Health Organization Regional Office for Africa; 2023.

Keywords: Lassa fever · Vaccine · Africa · Trials
Received: 21 October 2026
Accepted: 21 October 2026
Published: 21 October 2026
Peer review: Single-anonymized review by the Editorial Board · How we review
DOI: https://doi.org/10.5281/zenodo.23543427
License: © The Authors 2026. Distributed under CC BY 4.0
Journal: MP Journal of Medical Research · ISSN 3144-8402

Poster (PDF)Cite

[1] 1. Richmond JK, Baglole DJ. Lassa fever: epidemiology, clinical features, and social consequences. BMJ. 2003;327(7426):1271–5.

[2] 2. McCormick JB, Fisher-Hoch SP. Lassa fever. Curr Top Microbiol Immunol. 2002;262:75–109.

[3] 3. WHO. Lassa Fever – Nigeria. World Health Organization Disease Outbreak News; 2023. Available from: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON429

[4] 4. World Health Organization. An R&D Blueprint for Action to Prevent Epidemics: Plan of Action. Geneva: WHO; 2016.

[5] 5. Henao-Restrepo AM, Camacho A, Longini IM, et al. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease. Lancet. 2017;389(10068):505–18.

[6] 6. Tinto H, Ouoba T, et al. Challenges and opportunities for African-led vaccine research and development. Lancet Glob Health. 2022;10(3):e343–4.

[7] 7. Ayoub Ettaqui, Safiya Echcherif El Kettani, Meryem Chennaq et al. Human leishmaniasis in Morocco: a systematic review and meta-analysis — I. Species distribution, 22 September 2026, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-11085884/v1]

[8] 8. Ajayi NA, Ukwaja KN, et al. Challenges in conducting Lassa fever vaccine trials in Africa. J Infect Dev Ctries. 2021;15(1):1–5.

[9] 9. CEPI. Lassa fever vaccine programs. Coalition for Epidemic Preparedness Innovations; 2024. Available from: https://cepi.net/research_dev/vaccine-development/lassa-fever

[10] 10. Nigeria Centre for Disease Control. Lassa Fever Situation Report. Abuja: NCDC; 2023.

[11] 11. Adepoju P. Regulatory and logistical challenges for Lassa fever vaccine deployment. Nat Med. 2020;26(7):981.

[12] 12. AVAREF. African Vaccine Regulatory Forum Progress Report. WHO-AFRO; 2022.

[13] 13. Ogbu O, Ajuluchukwu E, Uneke CJ. Lassa fever in West African sub-region: an overview. J Vector Borne Dis. 2007;44(1):1–11.

[14] 14. WHO-AFRO. Roadmap for Lassa Fever Vaccine Development and Deployment in Africa. Brazzaville: World Health Organization Regional Office for Africa; 2023.