Side-by-side comparison
| Hantavirus vaccine | Lassa vaccine | |
|---|---|---|
| Disease | Hantavirus disease | Lassa fever |
| Family | Hantaviridae | Arenaviridae |
| Annual deaths | ~1 000–5 000 | ~5 000 |
| Licensed vaccines (2026) | Hantavax (Korea), inactivated (China) | None |
| Late-stage candidates | DNA vaccines for ANDV/SNV (Phase 1–2) | INO-4500 (DNA), MeV-NP (live recombinant) |
| Major funder | CEPI (limited) | CEPI, BARDA |
| Why slow | Small market, episodic outbreaks | Same; geographically concentrated |
| Trial endpoint | Antibody response (no licensure pathway via efficacy) | Same |
| Geography for trials | Patagonia, US Southwest | Nigeria, Sierra Leone |
| Outlook | mRNA candidates accelerating post-2026 cruise | CEPI Lassa portfolio expanding |
Why outbreak diseases of similar burden don't get vaccines
Both hantavirus and Lassa fever produce thousands of deaths annually but in geographically narrow, recurrent epidemics rather than pandemic spread. That makes Phase 3 efficacy trials operationally difficult — you cannot reliably enrol enough cases in a defined window. The pathway for licensure has therefore historically been antibody-based "animal rule" arguments rather than human efficacy data, which both regulators and funders treat cautiously.
What might change
mRNA platforms — proven by COVID-19 — accelerate the design-and-manufacture cycle dramatically. Both CEPI hantavirus and CEPI Lassa programmes have shifted weight toward mRNA candidates since 2024. The 2026 Atlantic hantavirus cruise outbreak, with its multi-country exposure footprint, may also unlock European regulatory pathways previously dormant.