GeoVax Labs, Inc. (Nasdaq: GOVX) announced the publication of preclinical research on bioRxiv showing 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 The findings, which have not yet been peer-reviewed, suggest that a single-dose regimen could achieve protection comparable to the currently recommended two-dose MVA regimen, a shift that could significantly simplify vaccination campaigns during outbreaks.
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 animal models, a single MVA-X vaccination provided complete protection at days 55, 90, and 150 after immunization, restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses even as circulating antibody levels declined. Notably, the single dose protected highly susceptible animals against lethal challenge with Clade I mpox virus, a strain associated with more severe disease in humans.
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." He added that reducing a two-dose regimen to a single shot could simplify deployment, accelerate completion of vaccination programs, and reduce the logistical burden of protecting at-risk populations during an outbreak.
The research supports GeoVax's broader strategy to expand the utility of the MVA platform. In parallel with efforts to improve immunogenicity and enable single-dose vaccination, the company is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. Together, these initiatives address dosing, manufacturing, and administration—three critical considerations for vaccine deployment, particularly in global health, resource-constrained, and biosecurity settings.
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." He added that the findings support further investigation of MVA-X as a next-generation, single-dose vaccine approach for orthopoxvirus infections, with an initial focus on mpox.
The manuscript is available as a preprint on bioRxiv under DOI 10.64898/2026.07.31.742137. The research was conducted by investigators from Washington State University and GeoVax. As a preprint, the findings have not been certified by peer review, and results from preclinical animal studies may not be predictive of results in humans.
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.
