Live virus vaccines such as yellow fever are generally contraindicated for immunosuppressed organ transplant recipients. However, transplanted persons residing in or travelling to yellow fever endemic regions are at great risk. Currently, a waiver of vaccination is given to transplant patients who wish to travel to a yellow fever endemic region. This multicenter study from Brazil reported 19 cases of inadvertent yellow fever vaccination in organ transplant patients (majority of these were kidney transplants). There were no significant adverse reactions. However, the small number of patients and the wide variation in immunosuppressive use makes the results difficult to generalize to all transplant recipients. Although this study does not change the recommendations to avoid live virus vaccines in transplant recipients, it does provide interesting information in cases of inadvertent vaccine administration.