Puzzling skin side effects stymie advance of promising HIV vaccine

One of the most promising attempts to reinvigorate the stalled quest for an HIV vaccine has hit a snag that might seem minor but has major consequences: delaying the larger trials needed to show whether the concept works. In small safety and immune tests of the innovative vaccine strategy, which relies on a series of messenger RNA (mRNA) shots, an unusually high percentage of recipients developed rashes, welts, or other skin irritations. “We are taking this very seriously,” says Carl Dieffenbach, who heads the Division of AIDS at the National Institute of Allergy and Infectious Diseases, which funded a recent phase 1 trial of the vaccine. Researchers want to understand the cause of the skin problems and how to minimize them before expanding tests of the vaccines, which are made by Moderna. “We would be moving more quickly if this finding had not been observed,” says Mark Feinberg, who heads IAVI , a nonprofit that is the vaccine’s major sponsor. The complex vaccine strategy involves injections of different mRNAs, encoding various pieces of HIV’s surface protein or the entire molecule, over the course of several months. The goal is to gradually guide the immune system’s B cells to produce so-called broadly neutralizing antibodies, or bnAbs, capable of stopping many different variants of the AIDS virus . People living with HIV on rare occasions eventually produce bnAbs, but no vaccine has ever done so—which has become the “holy ...
Source: ScienceNOW - Category: Science Source Type: news