GeoVax Labs, Inc. (Nasdaq: GOVX) announced on September 21, 2026, 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 highly pathogenic orthopoxviruses, including Clade I mpox virus. The findings suggest a potential shift from the conventional two-dose MVA regimen to a single-dose approach, which could significantly simplify vaccination campaigns during outbreaks.
The manuscript, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” reports that a single administration of MVA-X achieved protection comparable to a conventional two-dose MVA regimen across multiple orthopoxvirus challenge models. Notably, the single dose provided complete protection following lethal and high-dose challenges at Days 55, 90, and 150 after vaccination, restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses even as circulating antibody levels declined. The vaccine also protected highly susceptible animals against lethal challenge with Clade I mpox virus. The research was conducted in collaboration with investigators at Washington State University and funded by GeoVax. The manuscript is available as a preprint at bioRxiv under DOI 10.64898/2026.07.31.742137. It has not been certified by peer review, and findings from preclinical animal studies may not be predictive of results in humans.
MVA has an extensive safety record and is a critical vaccine platform for infectious disease preparedness and biosecurity. Currently, recommended MVA-based vaccination for mpox prevention generally involves a two-dose regimen. MVA-X was designed to explore the potential for single-dose protection through modifications intended to enhance the immune response while preserving the established attributes of the MVA platform. The study’s results indicate that enhancing early immune priming may provide a strategy for achieving durable MVA-mediated protection following a single vaccination.
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.”
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 strategy to advance the utility of MVA-based vaccines. In parallel with approaches 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 operational flexibility 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, which is advancing under an expedited regulatory pathway with plans to initiate a pivotal Phase 3 clinical trial in the second half of 2026. For more information, visit www.geovax.com.
