The last HIV vaccine in a late-stage trial has failed, researchers announced Wednesday, dealing yet another blow to the decades-long efforts to end the HIV/AIDS pandemic.
Called “Mosaico,” the trial began in 2019 as one of three late-phase HIV vaccine studies. Some 3,900 men and transgender people between the ages of 18 and 60 received four injections over 12 months.
While the vaccine was deemed safe, researchers found similar HIV infection rates between the placebo and vaccine groups.
Advanced trials of two other vaccines, dubbed “Uhambo” and “Imbokodo,” also yielded discouraging results in recent years.
“It’s obviously disappointing,” Dr. Anthony Fauci, the longtime head of the National Institute of Allergy and Infectious Diseases (NIAID), told NBC News of the vaccine’s failure.
The Post reached out to NIAID for comment. Fauci had previously vowed not to retire from the agency until a successful HIV vaccine was developed.
He expressed optimism that day will come, touting “other strategic approaches” in an interview with the New York Times on Wednesday.
“The ultimate prevention modality for any infection, particularly viral infection, is a vaccine that’s safe and effective,” Fauci, who retired last month, told the outlet. “That’s the reason why the field is going to continue to pursue very active research in that area.”
This halted trial — led by Janssen Pharmaceuticals, part of Johnson & Johnson — is the latest in a multitude of setbacks in the journey to ending the infectious disease four decades after it was discovered. The illness has since claimed the lives of more than 40 million people around the world.
As of 2021, 38.4 million people live with HIV. While there is no cure, life expectancy has increased with the use of antiretroviral therapy (ART) and other HIV medications. Pre-exposure prophylaxis (PrEP) can be taken to reduce the chance of infection.
Jennifer Kates, director of global health and HIV policy at the Kaiser Family Foundation, told NBC News the Mosaico trial failure is a “stark reminder of just how elusive an HIV vaccine really is and why this kind of research continues to be important.”
“Fortunately, there are a number of highly effective HIV prevention interventions already,” Kates added. “The challenge is to scale them up to reach all at risk.”