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 construct, designated MVA-X, provided durable protection against lethal orthopoxvirus challenges, including highly pathogenic Clade I mpox virus. The findings could have significant implications for outbreak response and global health preparedness by potentially reducing the need for a two-dose regimen.
The manuscript, "Single-dose Efficacy of a Next-Generation Mpox Vaccine Harnessing an Immunomodulatory Peptide," reports that a single administration of MVA-X protected against lethal and high-dose orthopoxvirus challenges at Days 55, 90, and 150 following vaccination, with efficacy comparable to a conventional two-dose MVA regimen. Importantly, the single dose 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 investigators at Washington State University and funded by GeoVax. The preprint is available at bioRxiv.
The potential significance of a single-dose MVA vaccine is considerable. Currently, MVA-based mpox vaccination generally requires two doses, which can complicate deployment during outbreaks, especially in resource-limited settings. A single-dose regimen could simplify logistics, accelerate vaccination campaigns, and reduce the burden on at-risk populations. 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 dosing, the MVA-X research is part of GeoVax's broader strategy to enhance the MVA platform. The company is also advancing continuous cell-line manufacturing and needle-free microarray patch delivery. Together, these innovations address key considerations in vaccine deployment: dosing, manufacturing, and administration. Dodd added, "Our objective is to build upon MVA's established attributes while developing approaches that could make MVA-based vaccines increasingly practical and deployable for global health, outbreak response and biosecurity."
The preclinical results also highlight the role of cellular immunity, particularly CD8+ T-cell responses, in controlling orthopoxvirus infection. 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 study showed that MVA-X generated durable antigen-specific CD8+ T-cell responses even as circulating antibody levels declined, suggesting that enhancing early immune priming may be key to durable single-dose protection.
GeoVax's priority program, GEO-MVA, is an MVA-based vaccine targeting mpox and smallpox that 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 maintains a global intellectual property portfolio supporting its infectious disease and oncology programs. For more information, visit www.geovax.com.
