Virus World

An experimental HIV vaccine that targets more strains of the virus than any other developed so far will start a late-stage clinical trial later this year. The ‘mosaic’ vaccine, which incorporates genetic material from HIV strains from around the world, also seems to have the longest-lasting effects of any others tested in people.

 

Small trials of the mosaic vaccine in people showed that it prompted an immune response, such as the production of antibodies, against HIV. But starting in September, scientists will test it in thousands of people to assess whether the vaccine provides any protection against HIV infection. The phase III trial will test the vaccine in transgender individuals and in men who have sex with men across the Americas and Europe. These communities are disproportionately affected by HIV, with about two-thirds of new infections in the United States occurring among gay and bisexual men, according to the US Centers for Disease Control and Prevention. The team running the trial, which they’ve named Mosaico, discussed the project during the 10th International AIDS Society Conference on HIV Science in Mexico City last week.

 

More than 100 HIV vaccines have been tested in people in the past three decades, but only one has demonstrated any kind of protection. In 2009, researchers announced the results of a study conducted in Thailand that showed that shortly after participants received an experimental vaccine, they were almost 60% less likely to become infected with HIV than those given a placebo. But the effects waned within a year — by the end of the 3.5-year study, vaccinated individuals were only 31% less likely to become infected. Small laboratory tests of the Mosaico vaccine in people showed that it elicited strong immune responses for at least two years after researchers administered it. These responses seem to be more durable than those observed in the Thai vaccine trial, says Guido Silvestri, an AIDS researcher at Emory University in Atlanta, Georgia. The latest Mosaico study will enrol 3,800 participants across 8 countries, including Argentina, Italy, Mexico, Poland and the United States. Half of the participants will get four vaccine injections over the course of a year, and the other half will receive a placebo.

 

News published on July 31 2019 in Nature:

https://doi.org/10.1038/d41586-019-02319-8