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, provides durable protection against highly pathogenic Clade I mpox virus and other orthopoxviruses. The findings could have significant implications for global health and biosecurity, as they suggest that the current two-dose MVA regimen for mpox prevention might be reduced to a single dose, simplifying deployment during outbreaks and reducing logistical burdens.
The manuscript, titled “Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide,” reports that a single administration of MVA-X provided complete protection following lethal and high-dose orthopoxvirus challenges at Days 55, 90, and 150 after vaccination. This protection was comparable to that achieved with a conventional two-dose MVA regimen. Notably, 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 full manuscript is available as a preprint on bioRxiv here.
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.”
The study also showed that MVA-X generated durable antigen-specific CD8+ T-cell responses despite declining circulating antibody levels, suggesting that enhancing early immune priming may be key to durable single-dose protection. 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.”
Beyond the mpox vaccine, GeoVax is pursuing a 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. These initiatives address dosing, manufacturing, and administration challenges, aiming to improve operational flexibility for MVA-based vaccines, especially in resource-constrained and biosecurity settings. GeoVax’s lead 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. For more information, visit www.geovax.com.
