New findings from the UNITY sub-study presented at AIDS 2026
Following the results of the UNITY trial, which did not show that tecovirimat reduced the time to resolution of mpox lesions, the sub-study was designed to further investigate the drug’s impact on viral dynamics and explore potential explanations for these findings.
Understanding the lack of clinical benefit of tecovirimat in mpox: new insights from the UNITY sub-study
Building on findings from the UNITY study, which did not demonstrate a reduction in the time to resolution of mpox lesions with tecovirimat treatment (B. Grinsztejn et al., IAS 2025), the UNITY sub-study was designed to further investigate these results and better understand the effect of tecovirimat on viral dynamics.
The sub-study specifically assessed the evolution of MPXV viral load and the time required for MPXV DNA to become undetectable, while also investigating tecovirimat pharmacokinetics and whether viral mutations associated with tecovirimat resistance could be detected. In total, 5,275 lesion, oral and rectal swab specimens from 442 participants were centrally analysed in the beginning of 2026.
These new findings were presented by Constance Daguerre (Saint Louis Hospital, Université Paris Cité, UMR1342) at AIDS 2026 in Rio de Janeiro, Brazil.
Key findings
The analyses provide new insights into viral DNA persistence across different anatomical compartments and highlight several factors that may be relevant when defining isolation recommendations:
- Samples taken from lesions had the highest and most persistent viral loads, underscoring their importance in the context of recommendations for isolating individuals.
- Treatment with tecovirimat did not reduce the time required to achieve undetectable MPXV DNA levels, but it did reduce MPXV viral loads in oral swabs on days 8 and 15, in correlation with CD4+ lymphocyte counts.
- These results lead to the conclusion that the compartment-specific profile may reflect differences in drug penetration or in the local viral dynamics of tecovirimat (C. Delaugerre et al., IAS 2026).
Together, these results contribute to a better understanding of viral persistence during mpox infection and provide important evidence to inform future recommendations for patient management and infection control.
International Collaboration on mpox research
Behind the results presented at AIDS 2026 was a coordinated effort involving partners across several countries and scientific disciplines. From sample collection and laboratory analyses to pharmacology and statistics, each team contributed a specific piece of the study.
The UNITY sub-study brought together three clinical centres across Argentina, Switzerland and Brazil, coordinated and supported by ANRS MIE, alongside laboratory, pharmacology and statistical expertise in France.
- Fundación Huésped (Argentina) — Clinical centre responsible for participant recruitment, follow-up and collection of clinical samples.
- Geneva University Hospitals – HUG (Switzerland) — Clinical centre responsible for participant recruitment, follow-up and collection of clinical samples
- Fiocruz (Brazil) — Clinical centre responsible for participant recruitment, follow-up and collection of clinical samples.
- ANRS MIE — UNITY Study sponsor. ANRS MIE also contributed to funding part of the study and coordinated the collection and international shipment of samples to France.
- AP-HP Saint Louis Hospital, Paris — Led the virological analyses, including the assessment of MPXV viral load and viral DNA persistence over time.
- INSERM U1207, Marseille — Received and processed the samples and conducted the immunological analyses, generating and contributing to the interpretation of immunological data.
- AP-HP / Gilles Peytavin — Conducted the pharmacokinetic and pharmacological analyses of tecovirimat and contributed to the interpretation of drug exposure data.
- OUH & INSERM IAME — Led the statistical analyses, including the development of the Statistical Analysis Plan, analysis and interpretation of the study results, and preparation of the scientific outputs