Adjuvanted inactivated rabies virus-vectored Lassa virus vaccine in healthy adults: a phase 1 trial.
Publication/Presentation Date
7-1-2026
Abstract
Lassa fever causes substantial morbidity and mortality in West Africa, and no licensed vaccine is available. We evaluated LASSARAB, an inactivated rabies virus-vectored Lassa virus (Josiah strain) glycoprotein complex vaccine. We conducted a randomized, controlled, dose-escalation phase 1 trial. Participants (total n = 54) received two intramuscular doses of LASSARAB containing 700 (n = 15), 1,400 (n = 15) or 2,800 (n = 14) relative units of antigen formulated with the TLR-4 agonist 3D-6-acyl PHAD-SE adjuvant, or licensed rabies vaccine control (n = 10), administered 28 days apart. This protocol-defined interim analysis reports the primary safety evaluation and secondary immunogenicity assessments through day 61. There were no prespecified hypotheses or formal power calculations. All primary safety end points demonstrated an acceptable safety profile. After dose 1, local solicited adverse events occurred in 86.7-100.0% of LASSARAB groups and 80% of controls; systemic events in 33.3-71.4% and 60.0% of controls. After dose 2, local solicited adverse events occurred in 66.7-86.7% of LASSARAB groups and 55.6% of controls; systemic events in 53.3-71.4% of LASSARAB groups and 55.6% of controls. Events were predominantly mild and self-limited. Unsolicited adverse events occurred in 28.6-60.0% of LASSARAB groups and 20.0% of controls. No serious adverse event, immune-mediated condition or sensorineural hearing loss occurred. Safety laboratory abnormalities occurred in 13.3-66.7% of LASSARAB groups and 30.0% of controls (14 mild, 6 moderate and none severe). After two doses, Lassa virus GPC IgG ELISA seroconversion (≥fourfold rise) was achieved in 100.0% (44 of 44) of LASSARAB recipients and 0.0% (0 of 10) of controls. Rabies glycoprotein IgG ELISA seroconversion (≥fourfold rise) and neutralizing antibody by rapid fluorescent focus inhibition test (RFFIT) seroprotection (≥0.5 IU ml
Volume
32
Issue
7
First Page
2511
Last Page
2521
ISSN
1546-170X
Published In/Presented At
Ortiz, J. R., Kurup, D., Kaufman, A. C., Ben Hamed, S., LaRocco, A. M., Lyke, K. E., Litts, S. M., Datta, S., Liang, Y., McGilvray, M. F., Losignor, J. A., Oshinsky, J. J., Palmer, K. V., Johnson-Mayo, I. P., Scher, G., Balakumar, U., Chandwani, A., Rapaka, R. R., Deming, M. E., Chua, J. V., … Schnell, M. J. (2026). Adjuvanted inactivated rabies virus-vectored Lassa virus vaccine in healthy adults: a phase 1 trial. Nature medicine, 32(7), 2511–2521. https://doi.org/10.1038/s41591-026-04429-z
Disciplines
Business Administration, Management, and Operations | Health and Medical Administration | Management Sciences and Quantitative Methods
PubMedID
42265408
Department(s)
Administration and Leadership
Document Type
Article