MVA-X Platform Demonstrates Single-Dose Durable Protection Comparable to Two-Dose Regimen

ATLANTA, GA - April 2, 2026 (NEWMEDIAWIRE) - GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines and immunotherapies for infectious diseases and cancer, today highlighted preclinical data presented at the World Vaccine Congress Washington 2026 supporting the potential for a single-dose Modified Vaccinia Ankara (MVA)-based mpox vaccine. The data demonstrate that a novel MVA vaccine construct incorporating an immunomodulatory peptide (“MVA-X”) achieved protective efficacy, comparable to the traditional two-dose MVA regimen, in a murine orthopoxvirus challenge model.

• The presentation, titled “Next-Generation MVA Mpox Vaccines: Harnessing an Immunomodulatory Peptide for Single-Dose Efficacy,” was delivered by Heather Koehler, Ph.D., of Washington State University, during the Immune Profiling track on April 1, 2026.
• Single-dose efficacy: the MVA-X vaccine construct achieved complete protection comparable to a two-dose MVA vaccine regimen in a lethal orthopox challenge model, while a single-administration of MVA showed only partial protection.
• Durable protection: Protective immunity was maintained through Day 150 post-vaccination, with 100% survival observed in both MVA-X (single-dose) and two-dose MVA groups.
• Robust viral control: MVA-X demonstrated significant reduction in lung viral burden, comparable to the two-dose MVA regimen.
• Improved clinical outcomes: MVA-X vaccinated animals exhibited minimal weight loss, reduced disease severity, and preserved lung structure.
• T cell-driven immunity: Protection in MVA-X vaccinated animals was independent of neutralizing antibodies, supported by enhanced CD4+ and CD8+ T cell responses.

Mechanistic Innovation

The MVA-X construct incorporates a peptide designed to transiently modulate the PD-1 immune checkpoint pathway, enhancing T cell activation and durability of immune response during vaccination.

This approach enables:

• Stronger and more sustained T cell responses
• Enhanced immune memory
• Potential for durable protection with fewer doses

This represents a novel application of immune checkpoint modulation within vaccine design.

“These findings provide an important proof-of-concept that the performance of MVA-based vaccines can be enhanced to potentially achieve single-dose protection,” said Mark Newman, Ph.D., Chief Scientific Officer of GeoVax. “The preclinical data demonstrates a clear biological signal that supports continued exploration of immune-enhanced MVA constructs.”

David A. Dodd, Chairman and Chief Executive Officer of GeoVax, added: “As mpox continues to emerge as a recurring global health and biodefense concern, the need for vaccines that are both durable and rapidly deployable has become increasingly clear. An MVA-X vaccine may offer the opportunity to meaningfully improve vaccination coverage, compliance, and outbreak response - particularly in resource-constrained or high-risk environments.”

Dodd further noted: “These results reinforce the strength and flexibility of the MVA platform that underpins our GEO-MVA program. With a defined regulatory pathway in place and preparations underway to initiate a Phase 3 immune bridging study, GeoVax is focused on advancing an MVA vaccine designed to expand global supply, support public health preparedness, and address the limitations of existing options.”

Strategic Context

• Supports Single-Dose Strategy for MVA-based immunization: Potential to simplify vaccination and improve real-world deployment
• Aligns with Market Need: Potential to addresses drawbacks of current mpox vaccines, including multi-dose requirements and durability

About the Study

The study evaluated MVA-X, an MVA-based vaccine incorporating an immunomodulatory peptide sequence designed to enhance T cell responses. In murine models, animals were challenged with high-dose vaccinia virus at multiple timepoints (Days 55, 90, and 150), with outcomes including survival, viral load, clinical pathology, and immune response.

About GeoVax

GeoVax Labs, Inc. is a clinical-stage biotechnology company focused on the development of vaccines and immunotherapies addressing high-consequence infectious diseases and solid tumor cancers. GeoVax’s priority program is GEO-MVA, a Modified Vaccinia Ankara (MVA)–based vaccine targeting mpox and smallpox. The program is advancing under an expedited regulatory pathway, with plans to initiate a pivotal Phase 3 clinical trial in the second half of 2026, to address critical global needs for expanded orthopoxvirus vaccine supply and biodefense preparedness. In oncology, GeoVax is developing Gedeptin®, a gene-directed enzyme prodrug therapy (GDEPT) designed to enhance immune checkpoint inhibitor activity. Gedeptin has completed a multicenter Phase 1/2 clinical trial in advanced head and neck cancer and is being advanced into combination strategies, including planned neoadjuvant and first-line settings. GeoVax’s broader pipeline includes the development of GEO-CM04S1, a next-generation COVID-19 vaccine candidate being evaluated in immunocompromised and other patient populations. GeoVax maintains a global intellectual property portfolio supporting its infectious disease and oncology programs and continues to evaluate strategic partnerships and funding opportunities aligned with its development priorities. For more information, visit www.geovax.com.

Forward-Looking Statements

This release contains forward-looking statements regarding GeoVax’s business plans. The words “believe,” “look forward to,” “may,” “estimate,” “continue,” “anticipate,” “intend,” “should,” “plan,” “could,” “target,” “potential,” “is likely,” “will,” “expect” and similar expressions, as they relate to us, are intended to identify forward-looking statements. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our financial condition, results of operations, business strategy and financial needs. Actual results may differ materially from those included in these statements due to a variety of factors, including whether: GeoVax is able to obtain acceptable results from ongoing or future clinical trials of its investigational products, GeoVax’s immuno-oncology products and preventative vaccines can provoke the desired responses, and those products or vaccines can be used effectively, GeoVax’s viral vector technology adequately amplifies immune responses to cancer antigens, GeoVax can develop and manufacture its immuno-oncology products and preventative vaccines with the desired characteristics in a timely manner, GeoVax’s immuno-oncology products and preventative vaccines will be safe for human use, GeoVax’s vaccines will effectively prevent targeted infections in humans, GeoVax’s immuno-oncology products and preventative vaccines will receive regulatory approvals necessary to be licensed and marketed, GeoVax raises required capital to complete development, there is development of competitive products that may be more effective or easier to use than GeoVax’s products, GeoVax will be able to enter into favorable manufacturing and distribution agreements, and other factors, over which GeoVax has no control.

Further information on our risk factors is contained in our periodic reports on Form 10-Q and Form 10-K that we have filed and will file with the SEC. Any forward-looking statement made by us herein speaks only as of the date on which it is made. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. We undertake no obligation to publicly update any forward-looking statement, whether as a result of new information, future developments or otherwise, except as may be required by law.

Company Contact:
info@geovax.com
678-384-7220

Media Contact:
Jessica Starman
media@geovax.com 

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