Nonclinical safety and biodistribution evaluation of HC009 mRNA vaccine against COVID-19 in rat.

mRNA-based technology has been evaluated in clinical trials for rapid control and prevention of emergencies and diseases. HC009, a mRNA vaccine encoding the full-length SARS-CoV-2 spike protein delivered via the QTsome platform, was tested in rats for immunogenicity, toxicity, and biodistribution. For immunogenicity and toxicity, rats received three intramuscular injections of HC009 at 3-week intervals followed by a 4-week observation period. In the biodistribution study, rats received a single intramuscular injection, with mRNA levels measured in organs at various time points. Results showed that HC009 elicited effective, long-lasting humoral immunity and Th1-biased cellular responses. The mRNA primarily localized to the injection site and spleen, with no observed vaccine-related toxicological reactions. These findings support HC009's potential for inducing an effective immune response with a favorable safety profile, warranting further clinical investigation.