V451 vaccine

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V451 vaccine
Vaccine description
Vaccine typeProtein subunit
Clinical data
Other namesSARS-CoV-2 Sclamp
Routes of
Legal status
Legal status
  • Terminated

V451 was a COVID-19 vaccine candidate developed by the University of Queensland and the Australian pharmaceutical company CSL Limited. The vaccine candidate used the University of Queensland's molecular clamp technology[1] and the MF59 adjuvant.[2]


V451 is a protein subunit vaccine. As part of the vaccine's design, researchers added "a fragment of one protein found on the HIV virus"[3] as a "ground-breaking molecular clamp technology".[4]

Terminated trial

The development of the vaccine was cancelled on 11 December 2020 during its Phase I trial, after a number of trial participants were found to give false positive test results for HIV antibodies when they did not in fact have HIV.[5][6] This was due to the HIV virus fragment used as a molecular clamp leading to "a partial antibody response" to HIV. This is an undesirable outcome as it will interfere with future HIV screening tests for affected participants.[7]

Nine days prior to the termination, on 2 December, the first emergency use authorisation had been granted to a COVID-19 vaccine; the Pfizer–BioNTech COVID-19 vaccine in the United Kingdom.[8] Following the termination of V451, vaccine production capacity by CSL Limited was diverted to the Oxford–AstraZeneca COVID-19 vaccine.[9]


  1. ^ "UQ-CSL V451 Vaccine". www.precisionvaccinations.com. Archived from the original on 2020-12-19. Retrieved 2020-12-11.
  2. ^ Meneguzzi J (13 November 2020). "Why a COVID-19 vaccine could further imperil deep-sea sharks". National Geographic.
  3. ^ Slezak, Michael (11 December 2020). "How the UQ coronavirus vaccine induced false-positive HIV test results and why scientists were prepared". ABC News.
  4. ^ Smyth J (11 December 2020). "Australia abandons local Covid vaccine over HIV test concerns". Financial Times.(subscription required)
  5. ^ "Covid: Australian vaccine abandoned over false HIV response". BBC News. 2020-12-11. Retrieved 2020-12-11.
  6. ^ Reuters Staff (2020-12-10). "BRIEF-CSL Says Will Not Progress UQ-CSL V451 COVID-19 Vaccine Candidate To Phase 2/3 Clinical Trials". Reuters. Retrieved 2020-12-11.
  7. ^ "Australia ends local COVID vaccine trials due to HIV false positives". Deutsche Welle. 11 December 2020.
  8. ^ "UK medicines regulator gives approval for first UK COVID-19 vaccine". Medicines and Healthcare products Regulatory Agency (MHRA). 2 December 2020. Archived from the original on 2 December 2020. Retrieved 2 December 2020.
  9. ^ "COVID-19 Update". www.csl.com. Retrieved 2021-01-31.

External links

  • Clinical trial number NCT04495933 for "A Study on the Safety, Tolerability and Immune Response of SARS-CoV-2 Sclamp (COVID-19) Vaccine in Healthy Adults" at ClinicalTrials.gov