The Only HIV Vaccine In Late-Stage Trial Fails

The only HIV vaccine in late-stage testing was stopped early after it failed to prevent HIV
(illustration of HIV cells)

Disappointing news as the only HIV vaccine in late-stage testing was stopped early after it failed to prevent HIV in men who have sex with men and transgender people in the Americas and Europe.

From NBC News:

Known as Mosaico, the trial was the product of a public-private partnership including the U.S. government and the pharmaceutical giant Janssen.

It was run out of eight nations in Europe and the Americas, including the U.S., starting in 2019. Researchers enrolled nearly 3,900 men who have sex with men and transgender people, all deemed at substantial risk of HIV.

The leaders of the study decided to discontinue the mammoth research effort after an independent data and safety monitoring board reviewed the trial’s findings and saw no evidence the vaccine lowered participants’ rate of HIV acquisition.

NBC News notes that Mosaico was a challenge to design and test in part due ethical issues related to PrEP, approved in the U.S. in 2012.

To prove a vaccine works, researchers must recruit participants who remain at substantial risk of HIV over time. So the Mosaico trial only accepted those who declined PrEP even though it increased their risk of HIV.

Still, there are other strategies to fight HIV being explored including an ongoing study called PrEPVacc in Eastern and Southern Africa which is exploring a combination of experimental H.I.V. vaccines and preventive drugs.

Read more at NBC News.