GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines against infectious diseases and therapies for solid tumor cancers, today highlighted a significant shift in the U.S. epidemiology of Clade I mpox, as reported by the U.S. Centers for Disease Control and Prevention (CDC). In its September 25 update, the CDC reported more than 60 laboratory-confirmed Clade I mpox cases across at least 20 states. Since August, an increasing proportion of these cases have occurred among individuals with no recent international travel or known links to travelers. Cases with presumed domestic transmission have now been reported in more than 10 jurisdictions, which the CDC said indicates a "likely transition to sustained Clade Ib transmission in the United States."
The CDC continues to assess the risk from the Clade I outbreak as low for most people in the United States, while noting that additional travel-related and domestically acquired Clade Ib cases are expected. David Dodd, Chairman and CEO of GeoVax, commented, "CDC's latest assessment represents an important change in the epidemiology of Clade Ib mpox in the United States. While the risk to the general population remains low, presumed domestic transmission across multiple jurisdictions reinforces the importance of continued surveillance, vaccination of appropriate at-risk populations and sustained preparedness."
Dodd continued: "Preparedness should not begin when an infectious-disease threat becomes a crisis. The appropriate time to strengthen vaccine capacity, diversify sources of supply and establish scalable manufacturing infrastructure is before those capabilities are urgently needed. The changing geographic footprint and public health threat of mpox is another reminder that infectious diseases do not respect national borders."
GeoVax is advancing GEO-MVA, its Modified Vaccinia Ankara (MVA)-based vaccine candidate for mpox and smallpox. Following formal guidance from the European Medicines Agency (EMA), the company is pursuing an expedited clinical development pathway, with traditional Phase 1 and Phase 2 trials not required, allowing the program to proceed directly to a pivotal Phase 3 immunobridging study comparing immune responses generated by GEO-MVA with those of the licensed MVA-BN comparator. GeoVax expects to initiate the 500-participant pivotal Phase 3 study in the fourth quarter of 2026, with results expected in mid-2027.
GEO-MVA is being developed to expand global access to MVA vaccines and scalable production capabilities, with the potential to provide governments and international public health organizations an additional source of MVA vaccine. The company believes GEO-MVA can become a strategic preparedness asset by supporting diversified vaccine supply, scalable manufacturing capacity, and greater supply resilience, while strengthening biosecurity and orthopoxvirus preparedness.
Dodd concluded: "Low risk to the general population today and the need for long-term preparedness are not contradictory. CDC's latest assessment illustrates why preparedness must anticipate changes in infectious-disease transmission rather than react to them after they occur. We believe diversified vaccine supply and scalable MVA manufacturing capacity can become increasingly important as the epidemiology of mpox continues to evolve."
The development is particularly noteworthy because the 2022 global mpox outbreak, including the large U.S. outbreak, was caused by Clade IIb. Clade I mpox has historically been associated with more severe disease and higher mortality than Clade II, though disease severity varies by viral subclade, population, and access to medical care. Recent Clade Ib cases identified in high-income countries have generally involved relatively mild illness, underscoring the importance of distinguishing the changing epidemiology of the virus from the immediate risk it poses to the general population.
The significance of the CDC's latest assessment extends beyond disease severity alone. The emergence of likely sustained Clade Ib transmission represents an important change in the geographic footprint and transmission dynamics of mpox in the United States. As recently as August, the CDC reported that sustained Clade Ib transmission had not been detected in the United States during 2024–2025. The September 25 assessment now indicates a likely transition toward sustained domestic transmission. Globally, Clade I outbreaks have continued in Central and Eastern Africa since late 2023, with subsequent geographic expansion beyond the region, including transmission in parts of Europe and introductions into the United States.
The evolving epidemiology follows other recent public-health preparedness actions, including updated CDC vaccination recommendations for certain U.S. travelers at increased risk and international initiatives to strengthen access to mpox vaccines and outbreak-response capabilities. For more information, visit www.geovax.com.
