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 evidence suggesting a likely transition to sustained domestic transmission of the Clade Ib subclade. In its September 25 update, the CDC confirmed 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 recent travelers. Cases with presumed domestic transmission have now been reported in more than 10 jurisdictions, prompting the CDC to state that these findings indicate a “likely transition to sustained Clade Ib transmission in the United States.” While the CDC continues to assess the risk from the Clade I outbreak as low for most people in the United States, it notes that additional travel-related and domestically acquired Clade Ib cases are expected.
This development marks a notable change from earlier U.S. surveillance. 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 points to a likely transition toward sustained domestic transmission. 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, although 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.
GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines against infectious diseases and therapies for solid tumor cancers, highlighted the CDC’s updated assessment. David Dodd, Chairman and Chief Executive Officer 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 protection against mpox and smallpox. Following formal guidance from the European Medicines Agency, GeoVax is progressing GEO-MVA through 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 generated by 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. The company believes GEO-MVA can become an important strategic preparedness asset by supporting diversified vaccine supply, scalable manufacturing capacity, and greater supply resilience. For more information, visit www.geovax.com.
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 news was originally distributed by NEWMEDIAWIRE.
