Researchers are developing what they hope will be the first successful vaccine against the highly contagious and difficult-to-treat Clostridioides difficile bacteria, using the technology behind the revolutionary mRNA vaccines that tackled the coronavirus that caused COVID-19.
In mice and in nonhuman primates, the experimental mRNA vaccine protected against first-time infections with C. difficile and also against relapsing infections, researchers reported in Science.
Earlier attempts at producing vaccines against C. difficile have been unsuccessful, although several are currently in development. A vaccine for C. difficile developed by Pfizer failed in a late-stage trial in 2022.
C. difficile can cause severe diarrhea and even deadly colon damage. The infections spread quickly, most often affecting people taking antibiotics and patients in hospitals or nursing homes. Roughly one-third of infected individuals will have recurrent infections.
Treatments include a lengthy course of strong antibiotics, which also kill off beneficial bacteria in the gut, and fecal transplants to deliver healthy bacteria.
Like the COVID vaccines, the C. difficile mRNA vaccine uses genetic material from the bacteria to train the immune system to recognize and respond in the event of future infections.
Immune cell responses “increased with vaccine dose and were significantly higher" than with more traditional vaccines, the researchers said.
Mice vaccinated with traditional-style vaccines all died within a day after being infected with the bacteria. Adding a booster to the old-style vaccines improved survival by 20%, but immunization with the mRNA vaccine improved survival to 100%.
“Antibiotics are not always an effective means of successfully treating really tough pathogens like C. diff, and we have only begun to scratch the surface of the full potential of mRNA vaccines for a host of infectious diseases,” study co-author Mohamad-Gabrie Alamehl, PhD, of Children's Hospital of Philadelphia said in a statement.
The results pave the way for trials in humans, the research team said.
The research was funded by the U.S. National Institutes of Health and by a BioNTech Sponsored Research Agreement.