Residual risk of infection with blood-borne viruses in potential organ donors at increased risk of infection: systematic review and meta-analysis

Revised nucleic acid test window periods: Applications and limitations in organ donation practice

BACKGROUND

Nucleic acid test window periods for HIV, HCV, and HBV facilitate estimation of the residual risk of unexpected disease transmission and assist clinicians in determining the timeframe in which a recently acquired infection is at risk of nondetection.

OBJECTIVES

Firstly, to provide revised estimates of the NAT window periods based on a currently used triplex NAT assay. Secondly, to examine their validity in organ donation and transplantation practice.

METHOD

Estimates were based on the Procleix Ultrio Elite Assay (Grifols Diagnostic Solutions Inc. California, USA). The manufacturer's X50 and X95 limits of detection (LOD) were utilised. Viral doubling times of 0.85, 0.45, and 2.56 days and conversion factors for IU per ml to copies per mL of 0.6, 3.4, and 5 were assumed for HIV, HCV, and HBV respectively. Window periods were derived from the X50 and X95 LODs, based on a range of potential inoculum volumes.

RESULTS

Calculated X50 window periods were 5.1 (4.5-5.8), 2.7 (2.4-2.9), and 16.6 (14.2-19.1) days for HIV, HCV, and HBV respectively. Calculated X50 window periods, based on whole body plasma volume, were 11.8 (10.3-13.3), 6.2 (5.6-6.8) and 36.7 (31.3-42.1) days respectively.

CONCLUSION

X50 NAT window periods were significantly shorter for HBV and HCV and sit at the lower range of previously published estimates for HIV .  Current modeling assumptions may not account for all unexpected transmission events and may no longer be suitable for application to organ donation and transplantation.

Cost-effectiveness of Kidney Transplantation From Donors at Increased Risk of Blood-borne Virus Infection Transmission

BACKGROUND

Demand for donor kidneys outstrips supply. Using kidneys from selected donors with an increased risk of blood-borne virus (BBV) transmission (hepatitis B virus and hepatitis C virus [HCV], human immunodeficiency virus) may expand the donor pool, but cost-effectiveness of this strategy is uncertain.

METHODS

A Markov model was developed using real-world evidence to compare healthcare costs and quality-adjusted life years (QALYs) of accepting kidneys from deceased donors with potential increased risk of BBV transmission, because of increased risk behaviors and/or history of HCV, versus declining these kidneys. Model simulations were run over a 20-y time horizon. Parameter uncertainty was assessed through deterministic and probabilistic sensitivity analyses.

RESULTS

Accepting kidneys from donors at increased risk of BBVs (2% from donors with increased-risk behaviors and 5% from donors with active or past HCV infection) incurred total costs of 311 303 Australian dollars with a gain of 8.53 QALYs. Foregoing kidneys from these donors incurred total costs of $330 517 and a gain of 8.44 QALYs. A cost-saving of $19 214 and additional 0.09 QALYs (~33 d in full health) per person would be generated compared with declining these donors. Increasing the availability of kidneys with increased risk by 15% led to further cost-savings of $57 425 and additional 0.23 QALY gains (~84 d in full health). Probabilistic sensitivity analysis using 10 000 iterations showed accepting kidneys from donors at increased risk led to lower costs and higher QALY gains.

CONCLUSIONS

Shifting clinical practice to accept increased BBV risk donors would likely produce lower costs and higher QALYs for health systems.

Inequities in organ and tissue donation and transplantation for sexual orientation and gender identity diverse people: A scoping review

Sexual orientation and gender identity (SOGI) diverse populations experience discrimination in organ and tissue donation and transplantation (OTDT) systems globally. We assembled a multidisciplinary group of clinical experts as well as SOGI-diverse patient and public partners and conducted a scoping review including citations on the experiences of SOGI-diverse persons in OTDT systems globally to identify and explore the inequities that exist with regards to living and deceased OTDT. Using scoping review methods, we conducted a systematic literature search of relevant electronic databases from 1970-2021 including a grey literature search. We identified and screened 2402 references and included 87 unique publications. Two researchers independently coded data in included publications in duplicate. We conducted a best-fit framework synthesis paired with an inductive thematic analysis to identify synthesized benefits, harms, inequities, justification of inequities, recommendations to mitigate inequities, laws and regulations, as well as knowledge and implementation gaps regarding SOGI-diverse identities in OTDT systems. We identified numerous harms and inequities for SOGI-diverse populations in OTDT systems. There were no published benefits of SOGI-diverse identities in OTDT systems. We summarized recommendations for the promotion of equity for SOGI-diverse populations and identified gaps that can serve as targets for action moving forward.

Recently Acquired Blood-borne Virus Infections in Australian Deceased Organ Donors: Estimation of the Residual Risk of Unexpected Transmission

Unexpected donor-derived infections of hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV are rare but important potential complications of deceased organ transplantation. The prevalence of recently acquired (yield) infections has not been previously described in a national cohort of Australian deceased organ donors. Donor yield infections are of particularly significance, as they can be used to gain insights in the incidence of disease in the donor pool and in turn, estimate the risk of unexpected disease transmission to recipients.

Methods

We conducted a retrospective review of all patients who commenced workup for donation in Australia between 2014 and 2020. Yield cases were defined by having both unreactive serological screening for current or previous infection and reactive nucleic acid testing screening on initial and repeat testing. Incidence was calculated using a yield window estimate and residual risk using the incidence/window period model.

Results

The review identified only a single yield infection of HBV in 3724 persons who commenced donation workup. There were no yield cases of HIV or HCV. There were no yield infections in donors with increased viral risk behaviors. The prevalence of HBV, HCV, and HIV was 0.06% (0.01-0.22), 0.00% (0-0.11), and 0.00% (0-0.11), respectively. The residual risk of HBV was estimated to be 0.021% (0.001-0.119).

Conclusions

The prevalence of recently acquired HBV, HCV, and HIV in Australians who commence workup for deceased donation is low. This novel application of yield-case-methodology has produced estimates of unexpected disease transmission which are modest, particularly when contrasted with local average waitlist mortality. Supplemental Visual Abstract; http://links.lww.com/TXD/A503.

Prevalence of Blood-Borne Viruses and Predictors of Risk in Potential Organ Donors in Australia

Internationally, the designation of a patient as an increased viral risk organ donor has been associated with lower utilisation rates. The actual prevalence of blood borne viruses in Australian potential organ donors, and the predictive performance of questionnaires administered to stratify this risk, remains unknown. We conducted a retrospective review of all patients who commenced workup for donation on the national database between 2014-2020. The prevalence of HIV, Active HBV and Active HCV in 3650 potential organ donors was 0.16%, 0.9%, and 2.2%, respectively. The behavioural risk profile was assessed in a subset of 3633 patients. Next-of-kin reported increased risk behaviours were associated with an increased prevalence of HCV but not of HIV or HBV (OR 13.8, p < 0.01, OR 0.3. p = 0.42, OR 1.5, p = 0.14). Furthermore, the majority of HIV and HBV infections occurred in potential donors without a disclosed history of increased risk behaviours. In this series, donors had a higher prevalence of HCV, and similar rates of HBV and HIV to the broader community. Behavioural transmission risks were poorly predictive of HIV and HBV. Rather than pre-transplantation behavioural risk screening, routine post-transplant recipient screening may provide a more powerful tool in mitigating the consequences of unexpected viral transmission.

Characteristics and Donation Outcomes of Potential Organ Donors Perceived to Be at Increased Risk for Blood-borne Virus Transmission: An Australian Cohort Study 2010-2018

BACKGROUND

Safely increasing organ donation to meet need is a priority. Potential donors may be declined because of perceived blood-borne virus (BBV) transmission risk. With hepatitis C (HCV) curative therapy, more potential donors may now be suitable. We sought to describe potential deceased donors with increased BBV transmission risk.

METHODS

We conducted a cohort study of all potential organ donors referred in NSW, Australia, 2010-2018. We compared baseline risk potential donors to potential donors with increased BBV transmission risk, due to history of HIV, HCV or hepatitis B, and/or behavioral risk factors.

RESULTS

There were 624 of 5749 potential donors (10.9%) perceived to have increased BBV transmission risk. This included 298 of 5749 (5.2%) with HCV (including HBV coinfections) and 239 of 5749 (4.2%) with increased risk behaviors (no known BBV). Potential donors with HCV and those with increased risk behaviors were younger and had fewer comorbidities than baseline risk potential donors (P < 0.001). Many potential donors (82 with HCV, 38 with risk behaviors) were declined for donation purely because of perceived BBV transmission risk. Most were excluded before BBV testing. When potential donors with HCV did donate, they donated fewer organs than baseline risk donors (median 1 versus 3, P < 0.01), especially kidneys (odds ratio 0.08, P < 0.001) and lungs (odds ratio 0.11, P = 0.006).

CONCLUSIONS

Many potential donors were not accepted because of perceived increased BBV transmission risk, without viral testing, and despite otherwise favorable characteristics. Transplantation could be increased from potential donors with HCV and/or increased risk behaviors.

Unexpected hepatitis B virus transmission after liver transplant from nucleic acid testing- and serology-negative liver donors who are hepatitis C viremic

The opioid epidemic has led to increased availability of organs for liver transplantation. The success of direct-acting antiviral therapy for hepatitis C (HCV) has led to the acceptance of HCV viremic donor organs. Nucleic acid testing (NAT) has led to increased detection of HCV and hepatitis B (HBV) in potential donors. A total of 36 patients underwent liver transplantation from donation after brain death donors who were HCV NAT-positive, and three of them were diagnosed with HBV several months after. All three recipients received livers from HCV viremic donors who were negative for HBV by serology and NAT. Soon after liver transplantation, HCV was treated, and all achieved sustained virologic response. They became HBV DNA-positive shortly thereafter. To date, there have been no reported cases of unexpected HBV transmission since universal donor NAT was implemented in 2013. We postulate that the inhibitory effect of HCV viremia on HBV may have prolonged the "NAT window period" in these donors beyond the 20-22 days quoted for solitary HBV infection. These cases highlight the need for more intensive and prolonged screening for HBV in recipients of livers from HCV viremic donors.

Successful Implementation of an Increased Viral Risk Donor Waiting List for Preconsented Kidney Transplant Candidates in Victoria, Australia

Supplemental Digital Content is available in the text.

Increased viral risk donors (IVRDs) with increased risk behaviors for blood-borne virus infection and negative nucleic acid testing have a low absolute risk of “window period” infection. Utilization and allocation of IVRD organs differ between jurisdictions.

New blood-borne virus infections among organ transplant recipients: An Australian data-linked cohort study examining donor transmissions and other HIV, hepatitis C and hepatitis B notifications, 2000-2015

BACKGROUND

Blood-borne viral infections can complicate organ transplantation. Systematic monitoring to distinguish donor-transmitted infections from other new infections post transplant is challenging. Administrative health data can be informative. We aimed to quantify post-transplant viral infections, specifically those transmitted by donors and those reactivating or arising new in recipients.

METHODS

We linked transplant registries with administrative health data for all solid organ donor-recipient pairs in New South Wales, Australia, 2000-2015. All new recipient notifications of hepatitis B (HBV), C (HCV), or human immunodeficiency virus (HIV) after transplant were identified. Proven/probable donor transmissions within 12 months of transplant were classified using an international algorithm.

RESULTS

Of 2120 organ donors, there were 72 with a viral infection (9/72 active, 63/72 past). These 72 donors donated to 173 recipients, of whom 24/173 already had the same infection as their donor, and 149/173 did not, so were at risk of donor transmission. Among those at risk, 3/149 recipients had proven/probable viral transmissions (1 HCV, 2 HBV); none were unrecognized by donation services. There were no deaths from transmissions. There were no donor transmissions from donors without known blood-borne viruses. An additional 68 recipients had new virus notifications, of whom 2/68 died, due to HBV infection.

CONCLUSION

This work confirms the safety of organ donation in an Australian cohort, with no unrecognized viral transmissions and most donors with viral infections not transmitting the virus. This may support targeted increases in donation from donors with viral infections. However, other new virus notifications post transplant were substantial and are preventable. Data linkage can enhance current biovigilance systems.