CSL406

CSL406 is an investigational self-amplifying messenger RNA (sa-mRNA) vaccine developed by CSL Behring (specifically through its CSL Seqirus subsidiary) in collaboration with Arcturus Therapeutics for the prevention of pandemic influenza caused by the H5N1 strain. Unlike conventional mRNA vaccines, CSL406 utilizes Arcturus's STARR technology, which incorporates a viral replicon derived from an alphavirus. This replicon enables the mRNA to replicate itself within host cells, leading to high-level and sustained expression of the target antigen—specifically the H5 hemagglutinin (HA) protein—at significantly lower doses than traditional mRNA platforms. This technology is designed to provide robust and durable immunity, improve manufacturing efficiency for rapid pandemic response, and potentially reduce dose-related reactogenicity. The vaccine is delivered using a lipid nanoparticle (LNP) formulation.

Other names

H5N1 sa-mRNA vaccineH-5N1 sa-mRNA vaccineH 5N1 sa-mRNA vaccineself-amplifying mRNA pandemic influenza A (H5N1) vaccine