In a new study, researchers modeled the transmission of Clostridioides difficile (C. diff) infections among patients in hospital cancer units. They found that most new infections were introduced by patients who were infected but not symptomatic at the time of admission, rather than by patients who were infected and symptomatic. The model provides a clearer picture of C. diff transmission events in oncology wards and could help inform protocols aimed at preventing future disease transmission in a highly susceptible population.