Global Impact of the COVID-19 Pandemic on Solid Organ Transplant

The Impact and Evolution of COVID-19 on Liver Transplant Recipients Throughout the Pandemic "Waves" in a Single Center

Liver transplant recipients (LTRs) have been considered a population group that is vulnerable to COVID-19 as they are chronically immunosuppressed patients with frequent comorbidities. This study describes the course of the SARS-CoV-2 disease from February 2020 to December 2023 along seven pandemic "waves". We carried out an observational study on 307 COVID-19 cases in a cohort of LTRs with the aim of evaluating the changes in the disease characteristics over time and determining the risk factors for severe COVID-19. An older age and serum creatinine level ≥ 2 mg/dL were found to be risk factors for hospital admission and respiratory failure. The use of calcineurin inhibitors was a protective factor for death, hospitalization, and respiratory failure from COVID-19. One hundred percent of patients who died (N = 12) were on mycophenolate mofetil, which was a determinant for respiratory failure. Azathioprine was associated with admission to the intensive care unit (ICU) and with invasive mechanical ventilation (IMV). Vaccination was a protective factor for hospitalization, respiratory failure, and mortality. The severe COVID-19 rate was higher during the first five waves, with a peak of 57.14%, and the highest mortality rate (21.43%) occurred in the fourth wave. The IMV and ICU admission rates did not show significant differences across the periods studied.

Changes in the epidemiology of kidney replacement therapy across Europe in 2020-the first year of the COVID-19 pandemic: an ERA Registry study

BACKGROUND

In 2020, the coronavirus disease 2019 (COVID-19) pandemic caused disruptions in kidney replacement therapy (KRT) services worldwide. The aim of this study was to assess the effect of the COVID-19 pandemic in 2020 on the incidence of KRT, kidney transplantation activity, mortality and prevalence of KRT across Europe.

METHODS

Patients receiving KRT were included from 17 countries providing data to the European Renal Association Registry. The epidemiology of KRT in 2020 was compared with average data from the period 2017-2019. Changes occurring during the first and second waves of the pandemic were also explored.

RESULTS

The incidence of KRT was 6.2% lower in 2020 compared with 2017-2019, with the lowest point (-22.7%) during the first wave in April. The decrease varied across countries, was smaller in males (-5.2%) than in females (-8.2%) and was moderate for peritoneal dialysis (-3.7%) and haemodialysis (-5.4%) but substantial for pre-emptive kidney transplantation (-23.6%). The kidney transplantation rate decreased by 22.5%, reaching a nadir of -80.1% during the first wave, and was greatest for living donor kidney transplants (-30.5%). While in most countries the kidney transplantation rate decreased, in the Nordic/Baltic countries and Greece there was no clear decrease. In dialysis patients, mortality increased by 11.4% and was highest in those 65-74 years of age (16.1%), in those with diabetes as the primary renal disease (15.1%) and in those on haemodialysis (12.4%). In transplant recipients, the mortality was 25.8% higher, but there were no subgroups that stood out. In contrast to the rising prevalence of KRT observed over the past decades across Europe, the prevalence at the end of 2020 (N = 317 787) resembled that of 2019 (N = 317 077).

CONCLUSION

The COVID-19 pandemic has had a substantial impact on the incidence of KRT, kidney transplant activity, mortality of KRT and prevalence of KRT in Europe with variations across countries.

A comparison of the epidemiology of kidney replacement therapy between Europe and the United States: 2021 data of the ERA Registry and the USRDS

BACKGROUND

This paper compares the most recent data on the incidence and prevalence of kidney replacement therapy (KRT), kidney transplantation rates, and mortality on KRT from Europe to those from the United States (US), including comparisons of treatment modalities (haemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KTx)).

METHODS

Data were derived from the annual reports of the European Renal Association (ERA) Registry and the United States Renal Data System (USRDS). The European data include information from national and regional renal registries providing the ERA Registry with individual patient data. Additional analyses were performed to present results for all participating European countries together.

RESULTS

In 2021, the KRT incidence in the US (409.7 per million population (pmp)) was almost 3-fold higher than in Europe (144.4 pmp). Despite the substantial difference in KRT incidence, approximately the same proportion of patients initiated HD (Europe: 82%, US: 84%), PD (14%; 13%, respectively), or underwent pre-emptive KTx (4%; 3%, respectively). The KRT prevalence in the US (2436.1 pmp) was 2-fold higher than in Europe (1187.8 pmp). Within Europe, approximately half of all prevalent patients were living with a functioning graft (47%), while in the US, this was one third (32%). The number of kidney transplantations performed was almost twice as high in the US (77.0 pmp) compared to Europe (41.6 pmp). The mortality of patients receiving KRT was 1.6-fold higher in the US (157.3 per 1000 patient years) compared to Europe (98.7 per 1000 patient years).

CONCLUSIONS

The US had a much higher KRT incidence, prevalence, and mortality compared to Europe, and despite a higher kidney transplantation rate, a lower proportion of prevalent patients with a functioning graft.

Clinical application of COVID-19 vaccine in liver transplant recipients

BACKGROUND

Solid organ transplant (SOT) activities, such as liver transplant, have been greatly influenced by the pandemic of coronavirus disease 2019 (COVID-19), a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Immunosuppressed individuals of liver transplant recipients (LTRs) tend to have a high risk of COVID-19 infection and related complications. Therefore, COVID-19 vaccination has been recommended to be administered as early as possible in LTRs.

DATA SOURCES

The keywords "liver transplant", "SARS-CoV-2", and "vaccine" were used to retrieve articles published in PubMed.

RESULTS

The antibody response following the 1st and 2nd doses of vaccination was disappointingly low, and the immune responses among LTRs remarkably improved after the 3rd or 4th dose of vaccination. Although the 3rd or 4th dose of COVID-19 vaccine increased the antibody titer, a proportion of patients remained unresponsive. Furthermore, recent studies showed that SARS-CoV-2 vaccine could trigger adverse events in LTRs, including allograft rejection and liver injury.

CONCLUSIONS

This review provides the recently reported data on the antibody response of LTRs following various doses of vaccine, risk factors for poor serological response and adverse events after vaccination.

Immediate Impact of the COVID-19 Pandemic on Heart and Kidney Transplantation and the Recovery Trends in 30 Developed and Less-Developed Countries

BACKGROUND The COVID-19 pandemic had multifaceted and disproportionate impacts on various countries. We investigated the decline of heart and kidney transplantation in 2020 and recovery trends in 2020, 2021, and 2022 in 30 developed and developing countries, considering COVID-19 incidence and mortality and pandemic-time economic variables. MATERIAL AND METHODS Data were obtained from reliable open databases. Nations were grouped by hierarchical cluster analysis into high-gross domestic product (GDP), mid-GDP, and low-GDP countries. Expected transplant numbers for 2020 to 2021 were estimated by the artificial neural network method using data from 2015 to 2019. Effect size and its inference were determined through the Hodges-Lemann estimate and Wilcoxon signed-rank test, respectively. The possible disproportionate effect was estimated by the Jonckheere-Tersptra test. Associations between transplantation and economic variables, COVID-19 caseload, and mortality were examined using Kendall rank correlation analysis. RESULTS All nations experienced a decline in 2020 and some real recovery in 2020 to 2022. For high-GDP countries, decline was insignificant and recovery was marginal; for mid-GDP countries, decline was significant for heart and deceased kidneys and recovery was modest; for low-GDP countries, decline was significant for heart, live kidneys, and deceased kidneys and recovery was marginal. The low-GDP countries were disproportionally negatively impacted, although the associations between the impact and economic variables, COVID-19 incidence, and COVID-19 mortality were statistically insignificant. CONCLUSIONS More inclusive studies of socioeconomic and cultural factors that affected the impact of the COVID-19 pandemic in different countries can be useful for better preparedness and reducing disruption in healthcare in future global pandemics.

Worldwide and Country-Specific Impact of the COVID-19 Pandemic on Heart Transplantation Volumes: A Longitudinal Analysis of 2020 and 2021

COVID-19 pandemic hampered operational efficiency of heart transplant (HT) programs worldwide. Little is known about the global and country-specific changes in HT volumes during the pandemic years 2020-2021. We aimed to describe the global and country-level impact of the COVID-19 pandemic on HT volumes in 2020-2021. This is a cross-sectional study of the Global Observatory on Donation and Transplantation, including the years 2019-2021. Among 60 countries that reported HT data in the years 2019-2020, we analyzed 52 countries with ≥1 transplant during each year. Overall, the number of HTs decreased during 2020 by 9.3% (1.82 to 1.65 PMP). While 75% (n = 39/52) of countries experienced a decrease in HT volumes in 2020, volumes were maintained/increased in the remaining countries. Countries with maintained HT volumes had a higher organ donation rate in 2020 compared to those with decreased volumes (P = 0.03), the only significant predictor of change in HT volumes (P = 0.005). In 2021, a 6.6% recovery from the previous year's drop in global HT rate was noticed, reaching 1.76 HT PMP. Only 1 in 5 countries with reduced volumes in 2020 recovered their baseline volumes in 2021. Only 30.8% of countries with maintained volumes in 2020 had continued growth in HT volumes in 2021. The latter group encompassed the United States of America, the Netherlands, Poland, and Portugal. Further work should define underlying causes of this heterogeneity in HT volume during the pandemic. Identifying policies and practices that helped certain countries mitigate the effect of the pandemic on HT activities may help other countries during similar health crises in the future.

Covid-19 positive donor utilization for heart transplantation: The new frontier for donor pool expansion

BACKGROUND

Hearts from COVID-19 positive donors (CPD) are being utilized for heart transplantation by some centers; however, this is in the setting of the lack of guidelines or robust evidence. The paucity of evidence is reflected in the recent Organ Procurement and Transplantation Network (OPTN) communication describing CPD utilization as an "unknown risk."

METHODS AND RESULTS

We analyzed the UNOS database for adult heart transplants performed between January 2021 to December 2022, and CPD comprised of a significant percentage of donors, being used in >10% of recipients in some UNOS regions. Between July 2022 and December 2022, 7.9% of heart transplants were with CPD, and in the same period Hepatitis C positive donors accounted for 7.1% and donation after circulatory death (DCD) accounted for 10.3%.

CONCLUSION

If the transplant community comes up with a standardized approach and guidance in using CPD hearts, this could provide an effective donor pool expansion strategy.

The COVID-19 Pandemic and Adult Cardiac Transplantation: Impact, Interventions, and Implications

In this review, we provide a comprehensive overview of the impact of the COVID-19 pandemic on adult heart transplantation. We highlight the decline in the number of adult transplantations performed throughout the pandemic as a consequence of restrictions imposed on individual programs and hospitals. There were challenges to maintaining cardiac transplant activity at multiple levels, including organ donation in intensive care units, logistical difficulties with organ procurement, and rapidly changing resource considerations at health system and jurisdictional levels. We also review the impact of COVID-19 on cardiac transplant recipients. Despite the high rates of morbidity and mortality observed during the initial phases of the pandemic among heart transplant patients infected with COVID-19, the availability of effective vaccines, pre-exposure prophylaxis, and specific antiviral therapies have drastically improved outcomes over time. Vaccines have proven to be safe and effective in reducing infections and illness severity, but specific considerations in the immunocompromised solid organ transplant population apply, including the need for additional booster doses to achieve sufficient immunisation. We further outline the strong rationale for vaccination before transplantation wherever possible. Finally, the COVID-19 response created a number of barriers to safe and efficient post-transplantation care. Given the need for frequent evaluation and monitoring, especially in the first several months after cardiac transplantation, the pandemic provided the impetus to improve virtual care delivery and explore noninvasive rejection surveillance through gene expression profiling. We hope that lessons learned will allow us to prepare and pivot effectively during future pandemics and health care emergencies.

Patterns and outcomes of COVID-19 donor utilization for heart transplant

BACKGROUND

The outcomes following COVID-19 positive donor (CPD) utilization for heart transplant are unknown.

METHODS

UNOS database was analyzed for heart transplants performed from the declaration of COVID-19 pandemic until September 30, 2022.

RESULT

Since the onset of pandemic, there were 9876 heart transplants reported. COVID-19 antigen or NAT results were available in 7698 adult donors within 14 days of donation, of which 177 (2.3%) were positive. There was no difference in recipient demographics, including age (COVID positive donor vs. negative: 55 vs. 56 years, p = .2) and BMI. Listing status 1 and 2 were similar in both groups (7% vs. 10% and 48% vs. 49% respectively, p = .4). Durable and temporary mechanical support were similar in both groups pre-transplant (both groups 33%, p = .9). There was no difference in days on the waitlist (median 31 days, p = .9). Simultaneous renal transplant rates were similar (11% vs. 10%, p = .9). CPD utilization has increased since the onset of the pandemic, and the adoption is present across most UNOS regions. Post-transplant, there was no difference in length of stay (median 16 vs. 17 days, p = .9) and acute rejection episodes prior to discharge (3% vs. 8%, p = .1). In survival analysis of 90-day follow up, number of deaths reported were comparable (5% in both groups, p = .9) Follow-up LVEF was comparable (62% vs. 60%, p = .4).

CONCLUSION

Active COVID-19 infection in donors did not affect survival or rejection rates in the short-term post-heart transplant.

Liver transplantation amidst the COVID-19 era: Our center’s experience

Coronavirus disease 2019 significantly impacted the liver transplant process worldwide. Consequently, it brought significant challenges and limitations to transplant policies and organ allocation forcing liver transplant centers to adjust their protocols to ensure maximum benefit and avoid harm to their patients. Our center, like many others, was obliged to adapt to the challenges. This paper provided an overview of the effects of coronavirus disease 2019 on liver transplantations and detailed our center’s experience and efforts during this unprecedented pandemic to serve as a guide for future public health crises.

Humoral and cellular response of COVID-19 vaccine among solid organ transplant recipients: A systematic review and meta-analysis

BACKGROUND

We aimed to analyze the humoral and cellular response to standard and booster (additional doses) COVID-19 vaccination in solid organ transplantation (SOT) and the risk factors involved for an impaired response.

METHODS

We did a systematic review and meta-analysis of studies published up until January 11, 2022, that reported immunogenicity of COVID-19 vaccine among SOT. The study is registered with PROSPERO, number CRD42022300547.

RESULTS

Of the 1527 studies, 112 studies, which involved 15391 SOT and 2844 healthy controls, were included. SOT showed a low humoral response (effect size [ES]: 0.44 [0.40-0.48]) in overall and in control studies (log-Odds-ratio [OR]: -4.46 [-8.10 to -2.35]). The humoral response was highest in liver (ES: 0.67 [0.61-0.74]) followed by heart (ES: 0.45 [0.32-0.59]), kidney (ES: 0.40 [0.36-0.45]), kidney-pancreas (ES: 0.33 [0.13-0.53]), and lung (0.27 [0.17-0.37]). The meta-analysis for standard and booster dose (ES: 0.43 [0.39-0.47] vs. 0.51 [0.43-0.54]) showed a marginal increase of 18% efficacy. SOT with prior infection had higher response (ES: 0.94 [0.92-0.96] vs. ES: 0.40 [0.39-0.41]; p-value < .01). The seroresponse with mRNA-12723 mRNA was highest 0.52 (0.40-0.64). Mycophenolic acid (OR: 1.42 [1.21-1.63]) and Belatacept (OR: 1.89 [1.3-2.49]) had highest risk for nonresponse. SOT had a parallelly decreased cellular response (ES: 0.42 [0.32-0.52]) in overall and control studies (OR: -3.12 [-0.4.12 to -2.13]).

INTERPRETATION

Overall, SOT develops a suboptimal response compared to the general population. Immunosuppression including mycophenolic acid, belatacept, and tacrolimus is associated with decreased response. Booster doses increase the immune response, but further upgradation in vaccination strategy for SOT is required.

Outcomes of Patients Receiving a Kidney Transplant or Remaining on the Transplant Waiting List at the Epicentre of the COVID-19 Pandemic in Europe: An Observational Comparative Study

Since the declaration of the COVID-19 pandemic, the number of kidney transplants (KT) performed worldwide has plummeted. Besides the generalised healthcare crisis, this unprecedented drop has multiple explanations such as the risk of viral transmission through the allograft, the perceived increase in SARS-CoV-2-related morbidity and mortality in immunocompromised hosts, and the virtual "safety" of dialysis while awaiting effective antiviral prophylaxis or treatment. Our institution, operating at the epicentre of the COVID-19 pandemic in Italy, has continued the KT programme without pre-set limitations. In this single-centre retrospective observational study with one-year follow-up, we assessed the outcomes of patients who had undergone KT (KTR) or remained on the transplant waiting list (TWL), before (Pre-COV) or during (COV) the pandemic. The main demographic and clinical characteristics of the patients on the TWL or receiving a KT were very similar in the two periods. The pandemic did not affect post-transplant recipient and allograft loss rates. On the contrary, there was a trend toward higher mortality among COV-TWL patients compared to Pre-COV-TWL subjects. Such a discrepancy was primarily due to SARS-CoV-2 infections. Chronic exposure to immunosuppression, incidence of delayed allograft function, and rejection rates were comparable. However, after one year, COV-KTR showed significantly higher median serum creatinine than Pre-COV-KTR. Our data confirm that KT practice could be safely maintained during the COVID-19 pandemic, with excellent patient- and allograft-related outcomes. Strict infection control strategies, aggressive follow-up monitoring, and preservation of dedicated personnel and resources are key factors for the optimisation of the results in case of future pandemics.

COVID-19 and Kidney Disease: Progress in Health Inequity From Low-Income Settings

The acute coronavirus disease-2019 (COVID-19) pandemic has had a significant impact on the incidence and prevalence of acute kidney injury and chronic kidney disease globally and in low-income settings. Chronic kidney disease increases the risk of developing COVID-19 and COVID-19 causes acute kidney injury directly or indirectly and is associated with high mortality in severe cases. Outcomes of COVID-19-associated kidney disease were not equitable globally owing to a lack of health infrastructure, challenges in diagnostic testing, and management of COVID-19 in low-income settings. COVID-19 also significantly impacted kidney transplant rates and mortality among kidney transplant recipients. Vaccine availability and uptake remains a significant challenge in low- and lower-middle-income countries compared with high-income countries. In this review, we explore the inequities in low- and lower-middle-income countries and highlight the progress made in the prevention, diagnosis, and management of patients with COVID-19 and kidney disease. We recommend further studies into the challenges, lessons learned, and progress made in the diagnosis, management, and treatment of patients with COVID-19-related kidney diseases and suggest ways to improve the care and management of patients with COVID-19 and kidney disease.

A Narrative Review COVID-19 in Solid-Organ Transplantation: Real-World Evidence From India

Worldwide, India ranks number 2 and 3 for COVID-19 burden and absolute transplant numbers, respectively. Here, we summarized our single and multicenter Indian studies on solid-organ transplant during the COVID-19 pandemic. During the pandemic, solid-organ transplants declined 40% to 50%. The mortality rate in COVID-19-positive kidney transplant recipients (11.6%) was lower in India compared with the developed world during the first wave and lower compared with maintenance hemodialysis patients (13% to 38%) but significantly higher compared with the nonimmunosuppressed general population (1% to 3%) in India. We contributed to National Organ and Tissue Transplant Organization transplant-related guidelines to increase safety and access to solid-organ transplant. We reported the safety and feasibility of remdesivir (n = 57) and convalescent plasma therapy (n = 10) in kidney transplant recipients. We reported 100% patient and graft survival without any complications related to COVID-19 in a large cohort of kidney transplant recipients who recovered from COVID-19 (n = 372) and a large cohort of kidney transplant recipients of living donors (n = 31) who recovered from COVID-19 without any change in induction and maintenance immunosuppression. COVID-19 disease severity and mortality in the second episode (reoccurring infection) was higher (46%) compared with the first episode (11.6%). There was 4.4% incidence of COVID-19-associated mucormycosis in kidney transplant recipients with mortality of 46% in the second wave. We reported COVID-19 vaccine safety with suboptimal efficacy in kidney transplant recipients and dialysis patients compared with the general population. Our report suggested that transplant with carefully selected COVID-19-recovered donors and patients may be feasible and safe, at least over the short term. Continued research is needed on vaccine efficacy, booster doses, and long-term follow up sequelae.