Seattle – Researchers said on February 3rd that they would terminate the world’s largest clinical trial of an HIV vaccine. The $120 million study, conducted by the HIV Vaccine Trials Network (HVTN) based at Seattle’s Fred Hutchinson Cancer Research Center, was launched more than three years ago and involved 5,407 volunteers in South Africa. “There was great hope and expectations around this vaccine candidate,” said Mitchell Warren, executive director of AVAC, a global HIV prevention organization that has been promoting vaccine development for 25 years. “It’s incredibly disappointing.”

The National Institute of Allergy and Infectious Disease (NIAID) and the Bill & Melinda Gates Foundation split the cost of the project, with the South African Medical Research Council providing facilities and personnel. “An HIV vaccine is essential to end the global pandemic, and we hoped this vaccine candidate would work. Regrettably, it does not,” said NIAID Director Anthony S. Fauci. “Research continues on other approaches to a safe and effective HIV vaccine, which I still believe can be achieved.”

The clinical trial, labeled HVTN 702, began with high hopes in October 2016. It enrolled 5,407 sexually active, HIV-negative men and women between 18 and 35 years of age at 14 sites across South Africa. Researchers randomly assigned half of the participants to receive two doses of the HIV vaccine, while the other half received placebo injections. The trial was supposed to last until July 2022. But initial evaluation of the data on January 23rd demonstrated that it was “futile” to continue. There were 129 infections in the vaccinated group and 123 in those who received the placebo. “There’s absolutely no evidence of efficacy,” said Glenda Gray, who heads the study and is president of the South African Medical Research Council (MRC). “Years of work went into this. It’s a huge disappointment.” The most effective way of preventing new HIV infections continues to be use of antiretrovirals, both as PrEP and to reduce viral load in HIV-positive patients to an undetectable level. (Seattle Gay News – Mike Andrew at

Please follow and like us: