This study is being conducted to find out how safe and effective different strategies of infection prevention are in comparison to each other, for preventing infection in patients with blood cancers. The best way to find out this information is to directly compare the effect of different treatment strategies in patients with blood cancers. We want to know how these different treatments impact on your health and your use of healthcare services. This research project uses an Adaptive Platform Design. This design allows the researchers to compare multiple infection prevention strategies within the same trial at the same time (rather than running separate trials), to analyse results as the trial occurs and to add new research questions during the course of the trial. The treatments that you may receive as part of the study will be determined by which domain(s) of the platform you participate in. By combining data collected within each domain as part of the platform, the researchers can investigate and compare treatment strategies and infection outcomes across a broader range of participants.