GeoVax Labs, Inc. (Nasdaq: GOVX) reported preclinical research showing that a single dose of an enhanced Modified Vaccinia Ankara (MVA) vaccine, designated MVA-X, provided durable protection against lethal orthopoxvirus challenges, including highly pathogenic Clade I mpox virus. The findings, published as a preprint on bioRxiv, suggest a potential path to single-dose mpox vaccination, which could significantly ease outbreak response and global health logistics.
The study, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” was conducted with Washington State University investigators and funded by GeoVax. In multiple animal models, a single MVA-X immunization delivered complete protection at Days 55, 90, and 150 after vaccination, matching the protection of a conventional two-dose MVA regimen. It also restricted viral replication and systemic dissemination, and protected highly susceptible animals against lethal Clade I mpox challenge. Notably, durable antigen-specific CD8+ T-cell responses were observed even as circulating antibody levels declined, underscoring the role of cellular immunity in controlling orthopoxvirus infection. The manuscript is available as a preprint at bioRxiv under DOI 10.64898/2026.07.31.742137, though it has not been peer-reviewed.
David Dodd, Chairman and CEO of GeoVax, said, “Two-dose administration has long been an accepted characteristic of MVA vaccination. These results provide encouraging preclinical evidence that it may be possible to achieve durable protection following a single vaccination utilizing MVA-X.” He noted that reducing a two-dose regimen to a single shot could simplify deployment, accelerate vaccination campaigns, and reduce logistical burdens during outbreaks.
Mark Newman, Ph.D., Chief Scientific Officer, added that the data support further investigation of MVA-X as a next-generation, single-dose vaccine approach for orthopoxvirus infections, with an initial focus on mpox.
The MVA-X research is part of GeoVax’s broader strategy to expand the utility of the MVA platform. In parallel, the company is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. Together, these initiatives address dosing, manufacturing, and administration—three critical considerations for vaccine deployment, especially in resource-constrained and biosecurity settings.
GeoVax’s priority program, GEO-MVA, is an MVA-based vaccine targeting mpox and smallpox. It is advancing under an expedited regulatory pathway, with plans to initiate a pivotal Phase 3 clinical trial in the second half of 2026. The company is also developing Gedeptin® for oncology. For more information, visit www.geovax.com.
These preclinical findings matter because they point to a potentially more practical mpox vaccine that could be deployed faster during outbreaks, when two-dose regimens are difficult to complete. If the approach translates to humans—where results may differ—it could improve vaccine coverage for at-risk populations and strengthen biodefense preparedness against orthopoxviruses. However, the data are from animal studies and the preprint has not been peer-reviewed, so clinical validation is still needed.
