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, provided durable protection against lethal orthopoxvirus challenges, including highly pathogenic Clade I mpox virus. The findings could significantly impact global preparedness for mpox outbreaks by reducing the need for a two-dose regimen, thereby simplifying deployment and accelerating vaccination programs.
The manuscript, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” reports that a single administration of MVA-X protected against lethal and high-dose orthopoxvirus challenges at Days 55, 90, and 150 following vaccination. Protection was comparable to a conventional two-dose MVA regimen. Importantly, MVA-X also protected highly susceptible animals against lethal challenge with Clade I mpox virus, a strain associated with more severe disease. The research was conducted in collaboration with Washington State University and funded by GeoVax. The preprint is available at https://www.biorxiv.org/content/10.64898/2026.07.31.742137v1.
MVA has an extensive safety record and is a critical vaccine platform for infectious disease preparedness and biosecurity. Currently recommended MVA-based mpox vaccination typically involves a two-dose regimen, which can pose logistical challenges during outbreaks. MVA-X was engineered to enhance early immune priming, potentially enabling durable protection with a single dose while preserving MVA’s established safety attributes. In the studies, a single MVA-X vaccination restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses despite declining circulating antibody levels. These cellular responses are thought to play a key role in controlling and clearing orthopoxvirus infection.
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 also noted that the findings support GeoVax’s broader strategy to expand the utility of the MVA platform, including innovations in dosing, manufacturing, and administration.
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 is part of GeoVax’s broader effort to advance MVA-based vaccines. In parallel, the company is developing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. These initiatives address critical considerations in vaccine deployment—dosing, manufacturing, and administration—with the potential to improve operational flexibility, especially in resource-constrained or biosecurity settings. GeoVax’s priority program, GEO-MVA, 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 maintains a global intellectual property portfolio and continues to evaluate strategic partnerships and funding opportunities aligned with its development priorities.
The manuscript is a preprint and has not been certified by peer review. Findings from preclinical animal studies may not be predictive of results in humans. For more information, visit www.geovax.com.
