Dengue infection in kidney transplant recipients during a major epidemic and the implementation of systematic donor screening: a cohort study.

Background: During Brazil's unprecedented dengue epidemic in 2023-2025, we develop a rationale for organ donor screening to mitigate the risk of donor derived transmission using rapid, widely available, and low-cost tests. Here we aimed to describe the epidemiology, clinical presentation, and outcomes among kidney transplant recipients (KTRs) who developed different routes of dengue infection and establish a policy for mitigating the risk of donor transmission. Methods: This study conducted at a large kidney transplant center in Brazil-Hospital do Rim (HRIM) examined dengue in KTRs through three components: initial cases of donor-derived infection that led to systematic donor screening; donor screening and adjudication for potential transmission from August 2023 to April 2025; and outcomes of vector-borne dengue among recipients followed at HRIM from December 2023 to July 2024. Donors were screened using immunochromatographic NS1 antigen and IgM rapid tests, with RT-PCR for those NS1-negative and IgM-positive. Findings: Before August 2023, we recorded four donor-derived transmissions from two deceased donors, resulting in three deaths. After that, among 1252 deceased donors screened, eight were NS1-positive and four had clinical evidence of dengue; these 12 donors were excluded from donation. Among 58 NS1-negative/IgM-positive donors, 38 were considered for donation. From these, 52 recipients were transplanted, with no confirmed donor-derived transmission. Among 1542 recipients of kidneys from NS1- and IgM-negative donors, 17 developed dengue within 30 days after transplantation: one had fatal transfusion-transmitted dengue, two had confirmed donor-derived transmission, ten had potential donor-derived transmission, and four were considered to have vector-borne infection acquired before transplantation. Every recipient with confirmed or potential donor-derived transmission identified during the screened period recovered from the infection. Lastly, among 12,402 KTRs on follow-up, we recorded 373 confirmed vector-borne cases. They were 50·0 years old, 203 were male (54·4%), 170 were female (45·6%), and 232 were White (62·2%). The case-fatality rate was 1·88%, compared with 0·10% in the general population during the same period. Interpretation: KTRs with vector-borne dengue experienced a high observed case-fatality rate. Organ or blood transmission led to life-threatening outcomes. The rapid test screening was associated with low transmission, and when it occurred, the risk of severe cases was mitigated. These findings support the incorporation of dengue screening strategies in endemic regions. Funding: Fundação Oswaldo Ramos.