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 highly pathogenic Clade I mpox virus and other orthopoxviruses. The findings, which show protection comparable to a conventional two-dose MVA regimen, could have significant implications for outbreak response and global health preparedness.
The study, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” was conducted in collaboration with Washington State University and funded by GeoVax. In multiple orthopoxvirus challenge models, a single MVA-X vaccination provided complete protection at Days 55, 90, and 150 following vaccination, restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses despite declining antibody levels. Importantly, it protected highly susceptible animals against lethal Clade I mpox challenge. The manuscript is available as a preprint on bioRxiv under DOI 10.64898/2026.07.31.742137 and has not been peer-reviewed.
MVA has an extensive safety record and is a critical platform for infectious disease preparedness and biosecurity. Currently, recommended MVA-based mpox vaccination typically involves a two-dose regimen. The MVA-X construct was designed to explore single-dose protection by modifying the vaccine to enhance early immune priming while preserving MVA’s established attributes. If validated in humans, a single-dose regimen could simplify deployment, accelerate vaccination program completion, and reduce logistical burdens during outbreaks, particularly in resource-constrained settings.
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.”
The research also highlights the importance of cellular immunity, particularly CD8+ T cells, in controlling and clearing orthopoxvirus infections. Mark Newman, Ph.D., Chief Scientific Officer of GeoVax, noted, “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 is part of GeoVax’s broader strategy to expand the utility of the MVA platform. In addition to improving immunogenicity for potential single-dose vaccination, the company is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. These initiatives address dosing, manufacturing, and administration challenges, aiming to improve operational flexibility for MVA-based vaccines, especially during outbreaks and in global health and biosecurity contexts. GeoVax’s lead program, GEO-MVA, is advancing under an expedited regulatory pathway with plans to initiate a pivotal Phase 3 trial in the second half of 2026. For more information, visit www.geovax.com.
