GeoVax Labs, Inc. (Nasdaq: GOVX) announced the publication of preclinical research on bioRxiv demonstrating that a single dose of an enhanced Modified Vaccinia Ankara (MVA) vaccine, designated MVA-X, provides durable protection against lethal orthopoxvirus challenges, including highly pathogenic Clade I mpox virus. The findings, which appear in the manuscript “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” suggest that it may be possible to achieve durable immunity with a single vaccination, potentially simplifying deployment during outbreaks and reducing logistical burdens.
The research, conducted in collaboration with Washington State University and funded by GeoVax, showed that a single MVA-X immunization provided complete protection at Days 55, 90, and 150 following vaccination against lethal and high-dose orthopoxvirus challenges. The single-dose regimen achieved protection comparable to a conventional two-dose MVA regimen, restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses despite declining circulating antibody levels. Importantly, MVA-X also protected highly susceptible animals against lethal challenge with highly pathogenic Clade I mpox virus. The manuscript is available as a preprint on bioRxiv under DOI 10.64898/2026.07.31.742137. The research is available at bioRxiv.
David Dodd, Chairman and CEO of GeoVax, commented, “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. The potential significance of such an innovation is considerable. During an outbreak, reducing a two-dose regimen to a single vaccination could simplify deployment, accelerate completion of vaccination programs and reduce the logistical burden associated with protecting at-risk populations.”
Dodd continued, “We also view these findings within a broader effort at GeoVax to expand the utility of MVA as a vaccine platform. We are advancing innovations directed at important considerations in vaccine deployment, including dosing, manufacturing and administration. Our objective is to build upon MVA’s established attributes while developing approaches that could make MVA-based vaccines increasingly practical and deployable for global health, outbreak response and biosecurity.”
Mark Newman, Ph.D., Chief Scientific Officer of GeoVax, added, “These data point toward an innovative approach to augmenting MVA potency and provide support for the important role of the cellular arm of the immune system, particularly CD8-positive T-cell responses, in controlling and clearing orthopoxvirus infection. These findings support further investigation to determine if augmentation of MVA potency can be developed as a next-generation, single-dose vaccine approach for protection against orthopoxvirus infections, with an initial focus on mpox.”
The MVA-X research represents one element of GeoVax’s broader effort to advance the utility of MVA-based vaccines. In parallel with approaches designed to improve immunogenicity and potentially enable single-dose vaccination, GeoVax is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. Together, these initiatives address three important considerations in vaccine deployment—dosing, manufacturing, and administration—with the potential to improve the operational flexibility of MVA-based vaccines, particularly during outbreaks and in global health, resource-constrained, and biosecurity settings.
GeoVax’s priority program is GEO-MVA, an MVA-based vaccine targeting mpox and smallpox. The program is advancing under an expedited regulatory pathway, with plans to initiate a pivotal Phase 3 clinical trial in the second half of 2026, to address critical global needs for expanded orthopoxvirus vaccine supply and biodefense preparedness. In oncology, GeoVax is developing Gedeptin®, a gene-directed enzyme prodrug therapy (GDEPT) designed to enhance immune checkpoint inhibitor activity. Gedeptin has completed a multicenter Phase 1/2 clinical trial in advanced head and neck cancer and is being advanced into combination strategies, including planned neoadjuvant and first-line settings. For more information, visit www.geovax.com.
