🩸 Lassa Fever Vaccine Tracker Dashboard
Tracking Lassa fever vaccine development to prevent viral hemorrhagic fever in West Africa. Lassa fever infects 100,000-300,000 people annually with ~5,000 deaths, primarily in Nigeria, Sierra Leone, Guinea, and Liberia. No licensed vaccine exists despite decades of research. Leading candidates include IAVI's rVSV-LASV vaccine and Bavarian Nordic's MVA-LASV, both in Phase 2. This tracker monitors the complete Lassa fever vaccine pipeline.
Lassa Fever Vaccines by Development Phase
🧬 Phase 2 Clinical Trials
Technology
rVSV vector expressing LASV glycoprotein
Phase 1 Results
Safe, strong antibody response
Trial Location
Nigeria, Liberia
Details: rVSV-LASV uses the same proven vesicular stomatitis virus platform as the licensed Ebola vaccine (Ervebo). Phase 1 trials (NCT03805984) in 60 healthy adults in Liberia showed excellent safety and robust antibody responses against Lassa virus glycoprotein. The vaccine induced neutralizing antibodies in 95% of participants by day 28. Phase 2 trials launched in 2023 in Nigeria and Liberia are assessing immunogenicity, safety, and durability of immunity in ~200 adults in endemic areas. Single-dose regimen. CEPI (Coalition for Epidemic Preparedness Innovations) provided $23 million funding.
Current Status: Phase 2 ongoing in West Africa. If successful, could advance to Phase 3 efficacy trials in endemic regions by 2025-2026. Represents most advanced Lassa fever vaccine candidate globally.
Technology
MVA vector + LASV antigens
Regimen
Two-dose schedule
Phase 1 Results
Well-tolerated, immunogenic
Description: MVA-LASV leverages Bavarian Nordic's Modified Vaccinia Ankara platform, proven safe in immunocompromised individuals. Phase 1 trials demonstrated safety and immunogenicity with two-dose regimen (0, 28 days). Vaccine encodes Lassa virus glycoprotein complex and nucleoprotein. Phase 2 studies evaluating optimal dosing and immune persistence. MVA platform advantages: non-replicating, safe in HIV+ individuals, established manufacturing.
Current Status: Phase 2 ongoing. Bavarian Nordic has extensive experience with MVA-based vaccines including smallpox (JYNNEOS) and Ebola vaccines.
🧪 Phase 1 Clinical Trials
Developer
MHRP/NIH/USAMRIID
Technology
VLP (glycoprotein + Z matrix)
Preclinical
Protective in guinea pigs, NHP
Description: ML29 VLP vaccine developed by US Military HIV Research Program (MHRP) in collaboration with NIH and USAMRIID. VLPs contain Lassa virus glycoprotein complex and Z matrix protein but no viral genome. Demonstrated complete protection in guinea pig and non-human primate challenge studies. Phase 1 trials assess safety, tolerability, and immunogenicity in healthy adults. Two-dose regimen with adjuvant.
Technology
mRNA-LNP platform
Advantage
Rapid manufacturing, scalable
Description: Moderna's mRNA vaccine encodes Lassa virus glycoprotein precursor (GPC). Leverages proven COVID-19 mRNA-LNP technology for rapid response to emerging threats. Early-phase trials initiated in 2023 assessing safety and immunogenicity. Single or two-dose regimen under investigation. Advantages include rapid manufacturing (weeks vs months), thermostability improvements, and potential for multivalent formulations covering Lassa and other arenaviruses.
Technology
DNA plasmid + electroporation
Target
Cellular + humoral immunity
Advantage
Thermostable, long shelf life
Description: DNA vaccine encoding Lassa virus glycoproteins delivered via electroporation to enhance uptake and immunogenicity. Phase 1 safety trials in healthy volunteers. DNA platform advantages: stable at room temperature, no cold chain required (critical for West Africa), induces both CD4+ and CD8+ T cell responses alongside antibodies. Preclinical studies showed protection in animal models.
🔬 Preclinical Development
Description: Self-amplifying RNA vaccines encoding Lassa glycoprotein with built-in replication machinery. Requires 10-100x lower doses than conventional mRNA. Preclinical studies in mice and guinea pigs demonstrate robust neutralizing antibody responses and protection against lethal Lassa virus challenge. Advantages: dose-sparing, enhanced immunogenicity, potential for single-dose regimen.
Description: ChAdOx1 or ChAdOx2 vectors expressing Lassa virus antigens. Same platform as COVID-19 AstraZeneca vaccine. Non-human primate studies show strong cellular and humoral immunity. Single-dose efficacy demonstrated in animal models. Could be manufactured at scale in existing facilities.
Description: Multivalent vaccine targeting Lassa fever plus other pathogenic arenaviruses (Junín, Machupo, Guanarito, Sabiá - causative agents of Argentine, Bolivian, Venezuelan, and Brazilian hemorrhagic fevers). VLP or mRNA platform encoding glycoproteins from multiple arenaviruses. Animal studies demonstrate broad cross-protective immunity.
Description: Recombinant Lassa glycoprotein displayed on ferritin or other nanoparticle scaffolds with adjuvant (Matrix-M, AS01). Highly stable, induces potent neutralizing antibodies. Guinea pig studies show dose-dependent protection. Advantages: no live components, suitable for immunocompromised, stable at 2-8°C.
Description: Live-attenuated Lassa virus reassortant (ML29 strain) combining attenuated segments with immunogenic glycoproteins. Single-dose protection in non-human primates. Concerns about reversion to virulence and safety in immunocompromised limit development. Requires high biosafety manufacturing (BSL-4). Historical approach with proven efficacy but safety challenges.