The U.S. Centers for Disease Control and Prevention (CDC) has reported a significant shift in the epidemiology of Clade I mpox in the United States, with more than 60 laboratory-confirmed 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, prompting the CDC to state that the data indicate a “likely transition to sustained Clade Ib transmission in the United States.” This marks a departure from earlier surveillance, which as recently as August had not detected sustained Clade Ib transmission during 2024–2025.
While the CDC continues to assess the risk to the general U.S. population as low, the emergence of presumed domestic transmission across more than 10 jurisdictions underscores the importance of continued surveillance, vaccination of at-risk populations, and sustained preparedness. The change is particularly notable because the 2022 global mpox outbreak was caused by Clade IIb, whereas Clade I has historically been associated with more severe disease. However, recent Clade Ib cases in high-income countries have generally involved mild illness, highlighting the need to distinguish between changing transmission dynamics and immediate risk.
GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines against infectious diseases, highlighted the CDC’s September 25 update and its implications. 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 emphasized that preparedness must be proactive rather than reactive. “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, a Modified Vaccinia Ankara (MVA)-based vaccine for mpox and smallpox. Following formal guidance from the European Medicines Agency, the company is pursuing an expedited clinical development pathway, with traditional Phase 1 and Phase 2 trials not required. GeoVax expects to initiate a 500-participant pivotal Phase 3 immunobridging study in the fourth quarter of 2026, with results expected in mid-2027. The study will compare immune responses generated by GEO-MVA with those of the licensed MVA-BN comparator.
The company believes GEO-MVA can become a strategic preparedness asset by supporting diversified vaccine supply, scalable manufacturing capacity, and greater supply resilience. 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 evolving situation follows other public-health actions, including updated CDC vaccination recommendations for certain travelers and international initiatives to strengthen mpox vaccine access. GeoVax maintains a global intellectual property portfolio and continues to evaluate strategic partnerships. For more information, visit www.geovax.com.
