11 December 2020
The COVID candidate stopped before later trials
CSL and UQ did not advance v451 to Phase 2/3. Antibodies to part of its molecular clamp interfered with some HIV tests. Follow-up testing found no HIV virus: this was diagnostic interference, not infection. The initial Phase 1 study continued to track the antibodies.
17 July 2025 · research published
The platform was redesigned
A peer-reviewed study described a second-generation clamp that avoided the original HIV-derived sequences. Researchers used it in VXB-241, a different candidate targeting respiratory syncytial virus (RSV) and human metapneumovirus (HMPV). This was further development of the technology, rather than a restart of the unchanged 2020 vaccine. Several authors disclosed intellectual property, shareholdings or paid roles connected to Vicebio.
Second-generation platform study · PLOS Pathogens · 17 July 2025
4 December 2025
Sanofi completed the acquisition
Sanofi completed its purchase of Vicebio, the company commercialising UQ’s molecular clamp technology. UQ confirmed the completed deal, reporting US$1.15 billion upfront and up to US$450 million in possible milestone payments. The figures concern the company transaction; they are not a payment of that whole amount to UQ, nor confirmation that future milestones have been paid.
Acquisition completed · Sanofi · 4 December 2025 · Completed deal and UQ connection · University of Queensland · 8 December 2025
1 June 2026 · analysis published online
The newer vaccine remained a research candidate
Published online on 1 June and in its July issue, the journal Vaccine reported a one-month interim analysis of VXB-241’s Phase 1 trial in older adults. Researchers reported immune responses to both viruses and no safety signal in that interim analysis. These early findings do not establish protection against disease or the outcome of longer follow-up. The official trial record, last updated in May 2026, lists the study as active and no longer recruiting. A trial listing is not regulatory approval. The authors disclosed financial links to Vicebio and other relevant interests.
Current Phase 1 trial record · ClinicalTrials.gov · updated 20 May 2026 · One-month Phase 1 interim analysis · Vaccine · online 1 June 2026
The evidence
Sources for this update
- 01Original decision · CSL · 11 December 2020
- 02Second-generation platform study · PLOS Pathogens · 17 July 2025
- 03Acquisition completed · Sanofi · 4 December 2025
- 04Completed deal and UQ connection · University of Queensland · 8 December 2025
- 05Current Phase 1 trial record · ClinicalTrials.gov · updated 20 May 2026
- 06One-month Phase 1 interim analysis · Vaccine · online 1 June 2026
Where the story stands
Ending FoundThe COVID vaccine stopped. Its technology found another path.
The original UQ–CSL COVID vaccine did not proceed beyond its initial trial because part of the clamp interfered with HIV tests. The tests did not establish HIV infection. Researchers subsequently redesigned the platform, and Sanofi completed its acquisition of the company commercialising it. Later trial findings show the technology being used in a different candidate for RSV and HMPV. That gives the cancelled COVID project and its technological aftermath a concrete outcome: the original vaccine stopped, while its redesigned technology continued into new research and a completed commercial deal. The newer vaccine remains experimental; its eventual approval would answer a different question.