Mpox Research Is Helping Scientists Prepare for a New Pandemic
June 4, 2025
The 2022 global mpox outbreak, which struck the U.S. with over 20,000 cases, led to widespread use of tecovirimat (TPOXX) under emergency protocols. A major clinical trial led by UC San Francisco has now confirmed that while TPOXX was safe, it did not accelerate recovery. This mirrors findings from a parallel trial in the Democratic Republic of the Congo. The trial's inclusive design—incorporating pregnant women and children—underscores the ethical imperative of equitable research. As mpox remains a WHO-declared public health emergency, these findings emphasize the need for more robust antiviral strategies and continued investment in outbreak-responsive clinical trials.
Tecovirimat (TPOXX) was a promising antiviral deployed during the 2022 mpox outbreak in the United States, which saw over 20,000 cases and nearly six dozen deaths. As the outbreak surged, physicians prescribed TPOXX under investigational protocols, banking on its efficacy against smallpox, a closely related virus. Yet new clinical trial data, led by UC San Francisco and echoed by research in the Democratic Republic of the Congo, reveal a sobering reality: while TPOXX was safe and well tolerated, it did not reduce recovery time for mpox patients.
The study’s significance lies not just in its clinical findings, but in its design. Pregnant women, children, and severely ill patients—often excluded from early trials—were included in an open-label arm, allowing researchers to gather vital data on high-risk populations. This equitable approach ensures future mpox therapies can be evaluated for those most vulnerable, addressing a historical gap in clinical research.
These results carry weight as the virus remains a global public health emergency, particularly in parts of Africa where Clade 1b mpox strains continue to circulate with more severe outcomes. While TPOXX’s utility is now in question, other investigational tools, including brincidofovir and monoclonal antibodies, are being explored. Still, these findings underscore an essential truth: evidence-based, randomized clinical trials must guide treatment protocols during outbreaks, not assumptions based on related pathogens.
Clinical research must remain central to outbreak response, enabling fast, reliable answers about drug efficacy and safety. The UCSF trial has now given the world critical clarity: TPOXX is not the answer to mpox. It’s time to shift focus toward new treatment strategies while continuing to uphold rigorous scientific standards that protect patients and advance global health.