Percentages of participants with yellow fever RNAaemia over time P-values were calculated with the Fisher’s exact test. Day 3: YFV-RNAaemia information of one control missing, Day 14: YFV-RNAaemia information of one MTX patient missing. Percentages show the percentage of MTX patients and controls with YFV-RNAaemia at each time point. YFV-RNAaemia was defined as ≥10 copies per microliter.