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]
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