The large deficit in donated organs required to provide transplantation to patients with end-stage organ disease is a global health crisis, exacerbated by regional differences in clinical practice and available resources. This deficit highlights the need for better tools to determine organ suitability for transplantation and to enhance the recovery of potential donor organs which are currently not transplanted due to concerns about organ quality. Novel organ assessment approaches, including epidemiological predictive models, advanced functional biometrics, and refined histological analysis, show potential to better identify donated organs suitable for transplantation. In addition, novel machine perfusion platforms have shown remarkable capacities to preserve and potentially modify injured organs, and a series of xenotransplantation experiments suggest a viable pathway to create a new organ supply. Collectively, these technologies will gradually alleviate the organ shortage and expand access to life-saving transplants.

Transplant medicine faces substantial challenges, as patients require lifelong immunosuppression to prevent graft rejection. Immunosuppressive regimens to date, while reasonably effective at preventing acute rejection, cause numerous health complications, compromising quality of life and patient survival. A shift towards personalised immunosuppression is needed to improve allograft health, reduce long-term adverse effects, and optimise post-transplant outcomes. This necessity has driven advancements in post-transplant monitoring and diagnostics. Innovative monitoring biomarkers and novel diagnostic modalities have been developed to advance transplant care, with many showing promise for widespread clinical implementation. With advances in artificial intelligence, algorithms have the potential to integrate multidimensional data on the immune system and allograft health, offering a comprehensive view of transplant status. This Series paper highlights the state of post-transplant immunosuppression, monitoring, and diagnostics, emphasising the transformative role of emerging innovations to personalise both allograft and patient care. Their implications could extend to xenotransplantation, further broadening their potential to redefine transplant medicine.

Advances in solid organ transplantation, such as improved organ preservation technologies and novel approaches to immunosuppression management, have the potential to improve outcomes in transplant recipients. However, despite these developments, there are persistent disparities in access to transplantation across, and within, certain countries. Low-income and middle-income countries have particularly low rates of transplantation, as well as less access to new technologies, mainly due to limited infrastructure and resources. Additionally, marginalised groups, especially racially and ethnically minoritised people and individuals from low socioeconomic backgrounds, might be most susceptible to these inequities worldwide. In this Series paper, we focus on how policies can advance equity in the field of transplantation, both within individual health systems and across different countries. We propose policy solutions to make progress towards equity in access to transplantation and better outcomes for all patients with end-stage organ disease who could benefit from transplantation.

The US Agency for International Development (USAID) is the largest funding agency for humanitarian and development aid worldwide. The aim of this study is to comprehensively evaluate the effect of all USAID funding on adult and child mortality over the past two decades and forecast the future effect of its defunding.

For the Spanish, French, Arabic, Russian and Chinese translations of the abstract see Supplementary Materials section.