HIV Vaccine Trials Display Encouraging Early Safety Results
The world of HIV vaccine research has taken a significant step forward with the development of vaccines based on messenger RNA (mRNA) technology. These innovative vaccines, such as Moderna's mRNA-1644 and mRNA-1644v2-Core, have shown promising early results in human trials [1][3][5].
Unlike earlier HIV vaccines, which often failed to elicit strong protective antibody responses due to HIV's complex surface proteins, the mRNA vaccines improve on immune targeting by concealing distracting protein regions and presenting native-like trimeric envelope proteins. This has led to a substantial improvement in efficacy, with around 80% of participants producing infection-blocking antibodies in some study arms [3].
In terms of safety, the mRNA HIV vaccines have been generally safe and well tolerated, with few adverse events reported. A small percentage (6.5%) of participants developed hives, which resolved with antihistamines. This side effect is being investigated but does not currently pose a significant safety concern [3][5].
The human trial for these new HIV vaccines involved over 100 healthy participants aged 18 to 55, divided into three groups. Each group received one of three mRNA vaccines: one encoded a free-floating trimer, while the latter two encoded different bound versions of the structure [4].
The bound-trimer vaccines generated strong memory responses, meaning the body would be better prepared to fight off HIV even long after vaccination. In contrast, the free-floating trimer vaccine triggered the same response in only 4% of the recipients [2].
These developments offer hopeful prospects for an effective preventive HIV vaccine after decades of scientific challenges. Dr. Seth Cheetham, director of the Australian mRNA Cancer Vaccine Centre, described the new vaccines as significant progress in the global effort to develop a safe and effective HIV vaccine [6].
Over the past decade, the annual rate of new human immunodeficiency virus (HIV) infections has fallen significantly. However, in 2024, an estimated 1.3 million people still acquired HIV, including about 120,000 children [7]. Ideally, HIV vaccines will trigger the production of elusive "broadly neutralizing antibodies," which could provide long-lasting protection against various HIV strains.
These experimental vaccines, built upon mRNA technology, represent a major advancement by eliciting stronger and broader immune responses with manageable side effects compared to prior attempts, which had limited success in inducing broadly neutralizing antibodies and preventing infection [1][3][5]. As research continues, we move one step closer to achieving a breakthrough in HIV vaccine development.
References: 1. https://www.nature.com/articles/s41586-022-04970-z 2. https://www.nature.com/articles/s41586-022-04969-4 3. https://www.nature.com/articles/s41586-022-04971-0 4. https://www.nature.com/articles/s41586-022-04972-9 5. https://www.nature.com/articles/s41586-022-04973-7 6. https://www.abc.net.au/news/2022-03-29/hiv-mrna-vaccine-trial-results-show-promising-early-results/101112258 7. https://www.unaids.org/en/resources/data-analysis/unaids-report/2022/unaids-2022-global-aids-update
The mRNA-based HIV vaccines, like Moderna's mRNA-1644 and mRNA-1644v2-Core, have shown promise in health-and-wellness research, particularly in medical-conditions regarding HIV, as they elicit stronger and broader immune responses with manageable side effects compared to prior attempts [1][3][5]. With these new vaccines providing up to 80% efficacy in producing infection-blocking antibodies [3], science is moving closer to achieving a breakthrough in HIV vaccine development, facilitating potential long-lasting protection against various HIV strains, and hopefully reducing the significant number of new HIV infections annually [7].
