Researchers have made progress in developing an mRNA-based vaccine against HIV by overcoming a key challenge related to the virus's complex surface proteins. Two vaccine candidates using mRNA technology, which encode membrane-anchored envelope trimers, have been shown to reliably trigger strong neutralizing antibody responses in both humans and animal models. A recent phase 1 trial demonstrated that this approach is generally well-tolerated and elicits higher response rates of neutralizing antibodies compared to previous soluble trimer vaccines. Approximately 80% of participants developed strong immunity. However, some tests revealed that the vaccine can cause unpleasant skin reactions. Despite these advances, experts caution that an approved HIV vaccine is still likely decades away. Additionally, the case of Loreen Willenberg, who has remained HIV-free despite immune-suppressing cancer treatment, continues to draw scientific interest.