The one HIV vaccine in a late-stage trial has failed. The grim news is a dampener for concerted HIV control efforts. 

The announcement was made by involved researchers Wednesday, NBCNews reported. The vaccine trial of the product named Mosaico was a public-private partnership between the U.S. government and the pharmaceutical giant Janssen.

The trial, began in 2019, was conducted in eight countries in Europe and the Americas, including the U.S. Nearly 3,900 men who’ve sex with men and transgender people were recruited for the study and were all considered at increased risk of HIV.

An independent data and safety monitoring board checked out the trial’s results and located no link between the vaccine and the speed of HIV acquisition. Consequently, the researchers took the choice to discontinue their work.

“It’s obviously disappointing,” Dr. Anthony Fauci, ex-head of the National Institute of Allergy and Infectious Diseases (NIAID) and an integral partner within the trial, said, as per the news outlet. He added “there are lots of other approaches” within the HIV-vaccine research field into consideration that he believes are promising.

“I don’t think that individuals should quit on the sector of the HIV vaccine,” Fauci said.

This failure isn’t surprising, in response to the experts. An analogous vaccine in a separate clinical trial called Imbokodo also failed in August 2021. The vaccine was tested amongst women in Africa. NIAID had spent $56 million in total for the 2 trials, in response to an agency spokesperson.

The vaccines in each trials used a standard cold virus to deliver mosaic immunogens. The idea was that the immunogen would trigger a strong immune response because it included genetic material from a mixture of HIV strains prevalent all over the world, in response to the National Institutes of Health. Mosaico was one step ahead in that it included a further element to widen the immune response. 

Within the Mosaico trial, participants between the ages of 18 and 60 got 4 injections over a yr. Following evaluation, the monitoring board found no difference within the HIV acquisition rate between the 2 groups- vaccine and placebo.

The undeniable fact that the Mosaico vaccine elicited what are often called non-neutralizing antibodies against HIV and never neutralizing antibodies was its limitation, Fauci noted.

“It’s becoming clear,” he said, “that vaccines that don’t induce neutralizing antibodies will not be effective against HIV.”

The trial’s failure is a “stark reminder of just how elusive an HIV vaccine really is and why this sort of research continues to be vital,” Jennifer Kates, director of world health and HIV policy at Kaiser Family Foundation, said.

“Fortunately, there are plenty of highly effective HIV prevention interventions already,” Kates added. “The challenge is to scale them up to achieve all in danger.”