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 showed protection comparable to a conventional two-dose MVA regimen, could significantly simplify vaccination campaigns during outbreaks and enhance global biosecurity preparedness.
The study, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” was conducted in collaboration with investigators at Washington State University and funded by GeoVax. In the reported studies, a single MVA-X vaccination provided complete protection following lethal and high-dose orthopoxvirus challenge at Days 55, 90, and 150 after vaccination. It also restricted viral replication and systemic dissemination, generated durable antigen-specific CD8+ T-cell responses despite declining circulating antibody levels, and protected highly susceptible animals against lethal challenge with highly pathogenic Clade I mpox virus. The manuscript is available as a preprint at bioRxiv.
The implications of these findings are substantial. Currently, MVA-based vaccination for mpox prevention generally requires a two-dose regimen. A single-dose option could simplify deployment, accelerate completion of vaccination programs, and reduce the logistical burden associated with protecting at-risk populations, especially in resource-constrained settings or during outbreaks. As David Dodd, Chairman and CEO of GeoVax, noted, “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.”
Beyond mpox, the results support GeoVax’s broader strategy to expand the utility of the MVA platform. The company is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery, addressing key considerations in vaccine deployment—dosing, manufacturing, and administration. These innovations could improve the operational flexibility of MVA-based vaccines for global health, outbreak response, and biosecurity.
Mark Newman, Ph.D., Chief Scientific Officer of GeoVax, commented, “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.” The 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.
GeoVax’s priority program is GEO-MVA, a 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. The company’s efforts to enhance MVA immunogenicity and enable single-dose vaccination could be critical in addressing global needs for expanded orthopoxvirus vaccine supply and biodefense preparedness.
The preprint has not been certified by peer review, and findings from preclinical animal studies may not be predictive of results in humans. Nonetheless, the data represent a promising step toward more practical and deployable MVA-based vaccines, with potential to impact public health responses to mpox and other orthopoxvirus threats.
