A new vaccine provides hope for treating and even preventing the highly contagious and difficult-to-treat Clostridioides difficile infection, more commonly known as C. difficile or C. diff. In animal models, this first mRNA-LNP C. difficile vaccine was found to protect against C. difficile first-time infections and relapsing infections by inducing a robust immune response, promote clearance of existing C. diff bacteria from the gut, and even overcome deficits in host immunity to protect animals after infection, according to researchers at the Perelman School of Medicine at the University of Pennsylvania and Children’s Hospital of Philadelphia. The results, published in the journal Science, will pave the way for clinical trials of the vaccine.