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 lethal orthopoxvirus challenges, including highly pathogenic Clade I mpox virus. The findings, which have not yet been peer-reviewed, suggest that it may be possible to achieve protection with a single vaccination rather than the conventional two-dose MVA regimen, a shift that could significantly simplify deployment during outbreaks and reduce logistical burdens.
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 immunization provided complete protection against lethal and high-dose orthopoxvirus challenges at Days 55, 90, and 150 post-vaccination. Notably, it also protected highly susceptible animals against lethal challenge with Clade I mpox virus, a strain associated with severe disease in humans. The protection was comparable to that achieved with a standard two-dose MVA regimen. The vaccine also restricted viral replication and systemic dissemination, and generated durable antigen-specific CD8+ T-cell responses even as circulating antibody levels declined, pointing to a critical role for cellular immunity in controlling 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 further noted that the findings align with GeoVax’s broader strategy to expand the utility of the MVA platform. The company is pursuing innovations in dosing, manufacturing, and administration. In addition to MVA-X, GeoVax is advancing continuous cell-line manufacturing and evaluating needle-free microarray patch delivery. Together, these initiatives aim to improve the operational flexibility of MVA-based vaccines, particularly in global health, resource-constrained, and biosecurity settings.
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 manuscript is available as a preprint on bioRxiv under DOI 10.64898/2026.07.31.742137. The research was funded by GeoVax, and the company’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 potential to achieve single-dose protection could be particularly impactful in outbreak scenarios, where rapid and widespread immunization is critical. However, the findings are from preclinical animal studies and may not predict results in humans. For more information, visit www.geovax.com.
