strongly advised. 2.3 Risk of donor transmitted infectious disease Acute or latent infections may be transmitted by the transplanted organ to the recipient. The intentional use of donors with certain infections may be considered where there is an acceptable risk of morbidity to the recipient, mitigated by serostatus matching or by antimicrobial prophylaxis and monitoring. The unexpected transmission of an infectious disease from an organ donor to recipient(s) is a rare event; however when it does occur, it is usually associated with significant morbidity and mortality.9 The concept of the “eclipse” or “window” period of infection is critical to understanding donor infectious disease risk mitigation. Following infection by a microbiological agent, there is a period of time during which no microbe can be readily detected in the host; this is classically called the “window period” for serological testing, or the “eclipse period” for NAT (see Figure 2.1: Generalised diagram of eclipse and window periods.). Unexpected transmissions are most likely to occur if the donor has recently acquired the infection and is still in the eclipse/ window period before detection is possible. Test results must be interpreted in the context of the patient’s full history, and the probability of false negative results needs to be considered against the donor’s background of any reported risk factors such as IVDU or high-risk sexual contact. Close attention must also be paid to travel history: potential donors with recent travel to or previous residence in areas where they may have been exposed to endemic pathogens warrant additional screening.10,11 In the case of a donor with recent risk exposure who is within the eclipse or window period of detection (e.g. a donor with intravenous drug overdose as the cause of death), whether to proceed with donation requires a consideration of the particular risks and benefits from the perspective of the intended recipient(s) and the informed consent of the recipient(s). Figure 2.1: Generalised diagram of eclipse and window periods. April 2021 version 1.5 13 2.3.1 Donors at increased risk of HIV, HBV and HCV HIV, HBV and HCV have been transmitted through organ transplantation. 10 The risk of unexpected viral hepatitis or HIV transmission can be reduced but not eliminated by obtaining a thorough patient history and performing serological testing and NAT assay. Donors are classified as “increased-risk” based on the presence of any of the risk factors listed in Table 2.2. In reality, the risk of donor-derived transmission of HIV, HBV and/or HCV exists on a spectrum, with IVDU and those known or suspected to have HIV, HBV or HCV associated with the highest degree of risk. It should be noted that information about behavioural risk factors obtained from the next of kin may be limited or inaccurate. The donor assessment interview must be supplemented with evidence from physical examination of the donor and/or their medical record. Donors whose social and medical history cannot be obtained should also be treated as increased risk. The presence of HIV, HBV or HCV in the donor is not necessarily a contraindication to donation. Decisions about whether to proceed with donation and transplantation will depend on recipient informed consent, the nature of the infection, other recipient clinical factors and the availability of effective treatment. Whereas the presence of HIV rules out donation in most circumstances, presence of HCV is becoming less of a barrier to transplantation given the availability of curative treatment. Similarly, recipients who are adequately immunised against or given prophylactic treatment for HBV may be transplanted with organs from donors with the potential to transmit HBV (see Sections 2.3.2.4 and 2.3.2.5). Where uncertainty exsists, advice sound be sought from a transplant hepatologist or infectious disease physician. Donor testing for HIV, HBV and HCV using serology and NAT should be undertaken using blood samples obtained from the donor prior to significant haemodilution. Such testing should be undertaken by laboratories with the appropriate accreditation (National Association of Testing Authorities [NATA] and Royal College of Pathologists of Australia [RCPA] or Therapeutic Goods Administraion [TGA, licensed]). Serological testing for HIV, HBV and HCV is performed as part of the evaluation of all donors, with results obtained prior to proceeding with organ transplantation. NAT testing for HIV, HBV and HCV is also recommended for all donors, with results required prospectively wherever logistically feasible. Table 2.2: Criteria for identifying organ donors at increased risk for HIV, HBV, and HCV infection (MSM= men who have sex with men; Derived from Seem12) * 10 weeks represents the longest serological window for detection of any of these three blood borne viruses (i.e. HCV, which has a serological window of ~70 days). People known or highly suspected to have HIV, HBV and/or HCV infection People who have injected drugs by intravenous, intramuscular, or subcutaneous route for non-medical reasons in the preceding 10 weeks* MSM in the preceding 10 weeks People who have been in lockup, jail, prison, or a juvenile correctional facility for more than 72 consecutive hours in the preceding 10 weeks People who have had sex in exchange for money or drugs in the preceding 10 weeks People who have had sex with a person in any