Safety and Immunogenicity of an rVSV Lassa fever vaccine candidate

Critical Summary The article by Malkin et al. presents the results of a phase 1, double-blind, randomized clinical trial evaluating the safety and immunogenicity of the rVSVΔG-LASV-GPC vaccine, a recombinant vesicular stomatitis virus–vectored candidate targeting Lassa fever. Given the absence of an approved Lassa fever vaccine despite the disease’s endemicity in West Africa and its pandemic potential, this study represents an important early step in vaccine development. The authors conducted the trial in the United States and Liberia, providing early insights into cross-regional safety and immune responses. The trial enrolled 114 healthy adults aged 18–50 years who received either a placebo or one of four escalating doses of the vaccine (2×10^4 to 2×10^7 PFU). An optional second dose was evaluated in a subset of participants at the highest dose level. Primary outcomes focused on reactogenicity and safety, while secondary measures included humoral and cellular immunogenicity and detection of vector-derived viral RNA in...