Mortality risk factors of COVID-19 infection in kidney transplantation recipients: a systematic review and meta-analysis of cohorts and clinical registries

The effectiveness of nirmatrelvir/ritonavir regimen in hospitalized renal transplant patients with prolonged COVID-19 infection: a multicenter clinical experience

OBJECTIVES

Effectiveness of nirmatrelvir/ritonavir (NR) in kidney transplant recipients (KTRs) infected COVID-19 for more than 5 days has not been evaluated.

METHODS

In this multicenter retrospective study, 85 KTRs with COVID-19 were enrolled, including 50 moderate, 21 severe, and 14 critical patients.

RESULTS

The median time from onset to starting NR treatment was 14 (IQR, 11-19) days. Before NR treatment, 96.5% patients reduced use of antimetabolites. They also stopped using calcineurin inhibitors (CNI) 12-24 hours before NR treatment, with CNI concentrations well-controlled during NR treatment. The use of intravenous corticosteroids increased with COVID-19 severity. The median time to reach viral negative conversion was 5 (IQR, 4-8) days for all patients. For moderate and severe COVID-19 patients, they had a low rate of ICU admission (1.4%), exacerbation requiring upgraded oxygen therapy (5.6%), and dialysis (2.8%); no intubation and mechanical ventilation, and no deaths were observed. Patients with critical COVID-19 had a low mortality rate (7.1%).

CONCLUSIONS

A regimen including NR for clearing SARS-CoV-2 along with reducing immunosuppressants and using intravenous corticosteroids is associated with lower rates of exacerbation and mortality in KTRs who have moderate to critical SARS-CoV-2 infection and the virus still present after 5 days.

Novel immunomodulatory properties of adenosine analogs promote their antiviral activity against SARS-CoV-2

The COVID-19 pandemic reminded us of the urgent need for new antivirals to control emerging infectious diseases and potential future pandemics. Immunotherapy has revolutionized oncology and could complement the use of antivirals, but its application to infectious diseases remains largely unexplored. Nucleoside analogs are a class of agents widely used as antiviral and anti-neoplastic drugs. Their antiviral activity is generally based on interference with viral nucleic acid replication or transcription. Based on our previous work and computer modeling, we hypothesize that antiviral adenosine analogs, like remdesivir, have previously unrecognized immunomodulatory properties which contribute to their therapeutic activity. In the case of remdesivir, we here show that these properties are due to its metabolite, GS-441524, acting as an Adenosine A2A Receptor antagonist. Our findings support a new rationale for the design of next-generation antiviral agents with dual - immunomodulatory and intrinsic - antiviral properties. These compounds could represent game-changing therapies to control emerging viral diseases and future pandemics.

ARDS in solid organ transplant recipients hospitalized for COVID-19 based on the 2023 new definition

BACKGROUND

Solid organ transplant recipients (SOTRs) are more likely to suffer complications after being infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

OBJECTIVES

We aimed to describe the clinical features of SOTRs infected with SARS-CoV-2 and to assess independent risk factors associated with the development of acute respiratory distress syndrome (ARDS) following COVID-19 infection in SOTRs based on the new ARDS definition.

METHODS

358 SOTRs infected with SARS-CoV-2 were recruited and divided into two groups, patients with ARDS (n = 81) and patients without ARDS (n = 277). Demographic data, initial laboratory findings, therapeutic measures, and outcome indicators were compared between the two groups. The association between the onset of ARDS and related factors was analyzed using a logistic regression model. A nomogram was created to estimate the probability of developing ARDS.

RESULTS

Approximately 22.6 % (81/358) of hospitalized SOTRs infected with SARS-CoV-2 developed ARDS. In comparison to patients without ARDS, those with ARDS presented with more underlying conditions, decreased lymphocyte counts and serum albumin levels, but increased levels of leukocytes, serum creatinine, nitrogen urea, uric acid, and inflammatory markers. Cerebrovascular disease, leukocyte counts, albumin levels, and IL-6 levels were independent risk factors for the development of ARDS in this population. Furthermore, a nomogram prediction model was created utilizing the aforementioned factors to facilitate early prediction of ARDS, exhibiting an AUC (area under curve) of 0.81.

CONCLUSIONS

Cerebrovascular disease, leukocyte counts, albumin levels, and IL-6 levels were independent risk factors for the development of ARDS following COVID-19 infection in SOTRs.

A prospective observational cohort study of covid-19 epidemiology and vaccine seroconversion in South Western Sydney, Australia, during the 2021-2022 pandemic period

BACKGROUND

It is known that COVID-19 disproportionally adversely affects the immunocompromised, including kidney transplant recipients (KTR), as compared to the general population. Risk factors for adverse outcomes and vaccine seroconversion patterns are not fully understood. Australia was uniquely positioned to reduce initial case numbers during the 2021-2022 pandemic period due to its relative isolation and several significant public health interventions. South-Western Sydney Local Heath District was one of the predominant regions affected.

METHODS

A single centre, prospective cohort study of prevalent renal transplant recipients was conducted between 25th July 2021 and 1st May 2022. Baseline characteristics, COVID-19 vaccination status, COVID-19 diagnosis and outcomes were determined from the electronic medical record, Australian vaccination register and Australian and New Zealand Dialysis and Transplant Registry. Assessment of vaccine-induced seroconversion was assessed with ELISA in a subpopulation. Analysis was performed using SPSS v.28.

RESULTS

We identified 444 prevalent transplant recipients (60% male, 50% diabetic, median age 58 years (Interquartile range (IQR)21.0) and eGFR 56 ml/min/1.73m2 (IQR 21.9). COVID-19 was identified in 32% (n = 142) of patients, of which 38% (n = 54) required hospitalisation and 7% (n = 10) died. At least one COVID-19 vaccination was received by 95% (n = 423) with 17 (4%) patients remaining unvaccinated throughout the study period. Seroconversion after 2 and 3 doses of vaccine was 22% and 48% respectively. Increased COVID-19 related deaths were associated with older age (aOR 1.1, 95% CI 1.004-1.192, p = 0.040), smoking exposure (aOR 8.2, 05% CI 1.020-65.649, p = 0.048) and respiratory disease (aOR 14.2, 95%CI:1.825-110.930, p = 0.011) on multi-variable regression analysis. Receipt of three doses of vaccination was protective against acquiring COVID-19 (aOR 0.48, 95% CI 0.287-0.796, p = 0.005) and death (aOR 0.6, 95% CI: 0.007-0.523, p = 0.011), but not against hospitalisation (p = 0.32). Seroconversion was protective for acquiring COVID-19 on multi-variable regression independent of vaccination dose (aOR 0.1, 95%CI: 0.0025-0.523, p = 0.011).

CONCLUSIONS

COVID-19 was associated with a high mortality rate. Older age, respiratory disease and prior smoking exposure may be risk factors for increased mortality. Vaccination of 3 doses is protective against acquiring COVID-19 and death, however not hospitalisation. Antibody response is protective for acquiring COVID-19, however seroconversion rates are low.

Immunogenicity and Safety of the Three-Dose COVID-19 Vaccine Regimen in Patients Receiving Renal Replacement Therapy: A Systematic Review and Meta-Analysis

Background

A three-dose regimen is the current standard for COVID-19 vaccination, but systematic data on immunogenicity and safety in chronic kidney disease patients remains limited.

Objectives

We conducted a meta-analysis on the immunogenicity and safety of three-dose COVID-19 vaccination in patients on renal replacement therapy (RRT).

Methods

Systematic literature search in four electronic databases yielded twenty eligible studies (2,117 patients, 94% of whom received mRNA vaccines) for meta-analysis.

Results

The overall seropositivity rate of anti-SARS-CoV-2 was 74.2% (95% CI: 65.0-83.4%) after three-dose COVID-19 vaccination. The seropositivity rate of anti-SARS-CoV-2 in kidney transplant recipients (KTRs) was 64.6% (95% CI: 58.7-70.5%), and 43.5% (95% CI: 38.5-48.6%) of non-responders after second dose became seropositive after third dose. The seropositivity rate of anti-SARS-CoV-2 was 92.9% (95% CI: 89.5-96.2%) in dialysis patients, and 64.6% (95% CI: 46.8-82.3%) of non-responders after second dose became seropositive after third dose. In KTRs, each year increase in transplant vintage was associated with 35.6% increase in anti-SARS-CoV-2 seropositivity (95% CI: 15.9-55.4%, p = 0.01). There were no serious adverse events attributed to vaccination in KTRs, and the commonest local and systemic adverse events were injection site pain and fatigue, respectively.

Conclusion

Three-dose COVID-19 vaccination regimen in patients on RRT is associated with reduced immunogenicity, especially in KTRs. There are no adverse events associated with third-dose COVID-19 vaccine in KTRs.

Cellular Immunobiology and Molecular Mechanisms in Alloimmunity-Pathways of Immunosuppression

Current maintenance immunosuppression commonly comprises a synergistic combination of tacrolimus as calcineurin inhibitor (CNI), mycophenolic acid, and glucocorticoids. Therapy is often individualized by steroid withdrawal or addition of belatacept or inhibitors of the mechanistic target of rapamycin. This review provides a comprehensive overview of their mode of action, focusing on the cellular immune system. The main pharmacological action of CNIs is suppression of the interleukin-2 pathway that leads to inhibition of T cell activation. Mycophenolic acid inhibits the purine pathway and subsequently diminishes T and B cell proliferation but also exerts a variety of effects on almost all immune cells, including inhibition of plasma cell activity. Glucocorticoids exert complex regulation via genomic and nongenomic mechanisms, acting mainly by downregulating proinflammatory cytokine signatures and cell signaling. Belatacept is potent in inhibiting B/T cell interaction, preventing formation of antibodies; however, it lacks the potency of CNIs in preventing T cell-mediated rejections. Mechanistic target of rapamycin inhibitors have strong antiproliferative activity on all cell types interfering with multiple metabolic pathways, partly explaining poor tolerability, whereas their superior effector T cell function might explain their benefits in the case of viral infections. Over the past decades, clinical and experimental studies provided a good overview on the underlying mechanisms of immunosuppressants. However, more data are needed to delineate the interaction between innate and adaptive immunity to better achieve tolerance and control of rejection. A better and more comprehensive understanding of the mechanistic reasons for failure of immunosuppressants, including individual risk/benefit assessments, may permit improved patient stratification.

Humoral and cellular immunity against different SARS-CoV-2 variants in patients with chronic kidney disease

Chronic kidney disease (CKD) patients are at higher risk of severe COVID-19. Humoral and cellular immunity from prior infection or vaccination are important for protection, but the neutralizing antibody (nAb) response against SARS-CoV-2 variants is impaired. We investigated the variant-specific nAb and T cell immunity among CKD patients. Adult CKD patients were recruited between August and October 2022. nAb against the SARS-CoV-2 (ancestral strains and four Omicron sublineages) and T cell response were measured using the live virus neutralization assay and interferon-gamma release assay (IGRA). The correlation between nAb/T-cell response and subsequent infection after recruitment were also determined. Among the 88 recruited patients, 95.5% had prior infection or had completed the primary vaccine series. However, only 77.3% had detectable nAb against at least one SARS-CoV-2 strains, 59.1% tested positive in IGRA, and 52.3% had detectable nAb and tested positive in the IGRA. The nAb geometic mean titers (GMTs) against XBB.1, BA.5 and BA.2.3.20 were significantly lower than those against BA.2 and ancestral strain. Prior SARS-CoV-2 infection was associated with elevated nAb and T cell response. More kidney transplant recipients (KTRs) showed absent nAb and T cell response (36.8% vs. 10.1%), despite a higher prevalence of vaccine booster in this population (94.7% vs. 50.7%). Lower levels of nAb titer and T cell response were significantly associated with subsequent infection. A considerable proportion of CKD patients, especially KTRs, showed absence of humoral and cellular protective immunity against SARS-CoV-2. Strategies to improve immunogenicity in this population are urgently needed.

Increasing SARS-CoV-2 seroprevalence among UK pediatric patients on dialysis and kidney transplantation between January 2020 and August 2021

BACKGROUND

Coronavirus disease 2019 (COVID-19) was officially declared a pandemic by the World Health Organisation (WHO) on 11 March 2020, as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread rapidly across the world. We investigated the seroprevalence of anti-SARS-CoV-2 antibodies in pediatric patients on dialysis or kidney transplantation in the UK.

METHODS

Excess sera samples were obtained prospectively during outpatient visits or haemodialysis sessions and analysed using a custom immunoassay calibrated with population age-matched healthy controls. Two large pediatric centres contributed samples.

RESULTS

In total, 520 sera from 145 patients (16 peritoneal dialysis, 16 haemodialysis, 113 transplantation) were analysed cross-sectionally from January 2020 until August 2021. No anti-SARS-CoV-2 antibody positive samples were detected in 2020 when lockdown and enhanced social distancing measures were enacted. Thereafter, the proportion of positive samples increased from 5% (January 2021) to 32% (August 2021) following the emergence of the Alpha variant. Taking all patients, 32/145 (22%) were seropositive, including 8/32 (25%) with prior laboratory-confirmed SARS-CoV-2 infection and 12/32 (38%) post-vaccination (one of whom was also infected after vaccination). The remaining 13 (41%) seropositive patients had no known stimulus, representing subclinical cases. Antibody binding signals were comparable across patient ages and dialysis versus transplantation and highest against full-length spike protein versus spike subunit-1 and nucleocapsid protein.

CONCLUSIONS

Anti-SARS-CoV-2 seroprevalence was low in 2020 and increased in early 2021. Serological surveillance complements nucleic acid detection and antigen testing to build a greater picture of the epidemiology of COVID-19 and is therefore important to guide public health responses. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical Course, Nosocomial, and Opportunistic Infections Among Kidney Transplant Recipients with COVID-19: A Retrospective Single Center Study

BACKGROUND

We report the results of an observational study, analyzing the clinical course of kidney transplant patients hospitalized for COVID-19 and comparing it with a control to determine if outcomes, nosocomial, and opportunistic infections were different between groups.

METHODS

An observational, retrospective, case-control, single-center study, including a group of kidney transplant adults diagnosed with COVID-19, from March 2020 to April 2022. Transplant patients hospitalized for COVID-19 comprised the cases. The control group consisted of non-transplanted adults, without immunosuppressive treatment, hospitalized for COVID-19, and matched by age, sex, and month at diagnosis of COVID-19. Study variables were collected, including demographic/clinical, epidemiologic, clinical/biological at diagnosis, evolutive, and outcome variables.

RESULTS

Fifty-eight kidney transplant recipients were included. Thirty required hospital admission. Ninety controls were included. Transplant recipients had a higher frequency of intensive care unit (ICU) admission, ventilatory support, and death. The relative risk for death was 2.45. When adjusted by baseline estimated glomerular filtration rate (eGFR) and comorbidity, only the risk for opportunistic infection remained high. Variables independently associated with death were dyslipidemia, eGFR at admission, MULBSTA score, and ventilatory support. Pneumonia by Klebsiella oxytoca was the most frequent nosocomial infection. Pulmonary aspergillosis was the most frequent opportunistic infection overall. Pneumocystosis and cytomegalovirus colitis were more frequent among transplant patients. The relative risk for opportunistic infection in this group was 1.88. Baseline eGFR, serum interleukin 6 level, and coinfection were independently associated with it.

CONCLUSIONS

Evolutive course of COVID-19 requiring hospitalization in renal transplant recipients was primarily determined by comorbidity and baseline kidney function. At equal comorbidity and renal function, there were no differences in mortality, ICU admission, nosocomial infection, and hospital stay. However, the risk for opportunistic infection remained high.

Cellular immune response of SARS-CoV-2 vaccination in kidney transplant recipients: a systematic review and meta-analysis

Background

Evidence has demonstrated inferior humoral immune responses after SARS-CoV-2 vaccination in kidney transplant recipients compared to the general population. However, data on cellular immune responses in this population have not been established.

Methods

We searched the MEDLINE, Scopus, and Cochrane databases and included studies reporting cellular immune response rates in kidney transplant recipients after receiving SARS-CoV-2 vaccines. Studies that reported factors associated with cellular immune responders or non-responders were also included (PROSPERO: CRD42022375544).

Results

From a total of 1,494 articles searched, 53 articles were included in the meta-analysis. In all, 21 studies assessed cellular immune response by interferon-γ enzyme-linked immunosorbent spot (IFN-γ ELISPOT), 22 studies used interferon-γ release assay (IGRA), and 10 studies used flow cytometric analysis. The pooled response rate after two doses (standard regimen) and three doses of vaccination was 47.5% (95%CI 38.4-56.7%) and 69.1% (95%CI 56.3-80.6%) from IFN-γ ELISPOT, 25.8% (95%CI 19.7-32.4%) and 14.7% (95%CI 8.5-22.2%) from IGRA, and 73.7% (95%CI 55.2-88.8%) and 86.5% (95%CI 75.3-94.9%) from flow cytometry, respectively. Recipients with seroconversion were associated with a higher chance of having cellular immune response (OR 2.58; 95%CI 1.89-3.54). Cellular immune response in kidney transplant recipients was lower than in dialysis patients (OR 0.24; 95%CI 0.16-0.34) and the general population (OR 0.10; 95%CI 0.07-0.14). Age and immunosuppressants containing tacrolimus or corticosteroid were associated with inferior cellular immune response.

Conclusion

Cellular immune response after SARS-CoV-2 vaccination in kidney transplant recipients was lower than in dialysis patients and the general population. Age, tacrolimus, and corticosteroid were associated with poor response. Cellular immune response should also be prioritized in vaccination studies.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022375544.

Outcomes and Effects of Vaccination on Sars-Cov-2 Omicron Infection in Kidney Transplant Recipients

BACKGROUND

Kidney transplant recipients (KTRs) are at high risk of COVID-19. Vaccination is significantly effective at preventing infection and reducing infection severity. Omicron infections are less severe than infections by previous strains, but breakthrough disease is more common. Thus, we conducted this study to observe the vaccine efficacy in our KTRs.

METHODS

During the surge in the Omicron variant, beginning in May 2022, we retrieved data from 365 KTRs who had received at least one dose of various COVID vaccines until June 30, 2022. Outcomes of the KTRs (n = 168) after at least the 2nd vaccination were assessed until September 30, 2022, before the border was opened for tourism.

RESULTS

The antibody response in KTRs after the 1st and 2nd doses of SARS-CoV-2 vaccines demonstrated a significant increase from the 1st dose (median: 0.4; IQR: 0.4-8.4 U/mL, P < .001) to the 2nd dose (median: 57.5; IQR: 0.4-799.2 U/mL), and the response rate rose from 32% to 65% (P < .001). SARS-CoV-2 infection was identified in 14/365 (3.8%) patients after at least the 1st dose and 7/187 (3.7%) patients at least 7 days beyond the 2nd dose. Most KTRs had a mild course, but 3 (17%) were hospitalized due to pneumonia.

CONCLUSIONS

Our data demonstrate a lower response rate and anti-S titers after 2nd dose vaccination in KTRs than in the general population, but a lower incidence of SARS-CoV-2 infection after vaccination was observed during the Omicron outbreak. Owing to the breakthrough infections found in ordinarily vaccinated KTRs, we must emphasize the importance of vaccination and boosters to prevent severe illness, hospitalizations, and death among those developing infections.

Nirmatrelvir/ritonavir treatment in SARS-CoV-2 positive kidney transplant recipients - a case series with four patients

BACKGROUND

Despite vaccination coronavirus disease 2019 (COVID-19)-associated mortality caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains high in kidney transplant recipients. Nirmatrelvir is a protease inhibitor with activity against SARS-CoV-2. Nirmatrelvir reduces the risk for mortality and hospitalization, which is approved for treating adults at risk for severe disease. Nirmatrelvir is metabolized by the cytochrome P-450 (CYP) 3A4 isozyme CYP3A4 and is therefore co-administered with the irreversible CYP3A4 inhibitor ritonavir, which results in a drug interaction with tacrolimus. A limited number of patients with nirmatrelvir/ritonavir and tacrolimus therapy after kidney transplantation have been reported to date. It has been reported that tacrolimus was paused during the five-day nirmatrelvir/ritonavir therapy and subtherapeutic tacrolimus levels were observed after finishing nirmatrelvir/ritonavir in two patients. Therefore, optimization of tacrolimus dosing is urgently needed in transplant recipients receiving nirmatrelvir/ritonavir treatment.

CASE PRESENTATION

Here, we present our first-hand experience with four patients receiving tacrolimus therapy following kidney transplantation and nirmatrelvir/ritonavir therapy due to COVID-19. Tacrolimus was paused during nirmatrelvir/ritonavir therapy in all patients, which resulted in stable therapeutic tacrolimus levels. Tacrolimus was continued directly after finishing nirmatrelvir/ritonavir to avoid subtherapeutic levels in the first patient treated. This patient received his usual tacrolimus maintenance dose, which resulted in toxic levels. Based on this observation, tacrolimus therapy was continued 24 h after finishing nirmatrelvir/ritonavir treatment at a reduced dose in the subsequent patients. In these patients, therapeutic to supratherapeutic tacrolimus levels were observed despite the therapeutic break and dose reduction.

DISCUSSION AND CONCLUSIONS

Based on altered CYP3A4 metabolism, tacrolimus levels have to be closely monitored after treatment with nirmatrelvir/ritonavir. Our study suggests that tacrolimus treatment should be paused during nirmatrelvir/ritonavir medication and be continued 24 h after completing nirmatrelvir/ritonavir therapy at a reduced dose and under close monitoring. Based on the limited number of patients in this study, results must be interpreted with caution.

Effectiveness of vaccination against SARS-CoV-2 and the need for alternative preventative approaches in immunocompromised individuals: a narrative review of systematic reviews

INTRODUCTION

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including administration of booster doses, continues to be the most effective method for controlling COVID-19-related complications including progression to severe illness and death.However, there is mounting evidence that more needs to be done to protect individuals with compromised immune function.

AREAS COVERED

Here, we review the effectiveness of COVID-19 vaccination in immunocompromised patients, including those with primary immunodeficiencies, HIV, cancer (including hematological malignancies), solid organ transplant recipients and chronic kidney disease, as reported in systematic reviews/meta-analyses published over a 12-month period in PubMed. Given the varied responses to vaccination patients with compromised immune function, a major goal of this analysis was to try to identify specific risk-factors related to vaccine failure.

EXPERT OPINION

COVID-19 remains a global problem, with new variants of concern emerging at regular intervals. There is an ongoing need for optimal vaccine strategies to combat the pandemic. In addition, alternative treatment approaches are needed for immunocompromised patients who may not mount an adequate immune response to current COVID-19 vaccines. Identification of high-risk patients, and the introduction of newer antiviral approaches such as monoclonal antibodies, will offer physicians therapeutic options for such vulnerable individuals.

Outcome of Transplant Recipients Infected with Omicron BA.1 and BA.2: A Single-Center Retrospective Study in Saudi Arabia

The outcome of transplant recipients is variable depending on the study population, vaccination status and COVID-19 variants. Our aim was to study the impact of Omicron subvariants on the mortality of transplant recipients. We reviewed the results of SARS-CoV-2 whole genome sequence of random isolates collected from 29 December 2021 until 17 May 2022 in King Faisal Specialist Hospital and Research center, Jeddah (KFSHRC-J), Saudi Arabia performed as hospital genomic surveillance program for COVID-19 variants. We included 25 transplant patients infected with confirmed Omicron variants.17 (68%) and 8 (32%) patients had Omicron BA.1 and BA.2, respectively. 12 (68%) patients had renal transplants. Only 36% of patients received three doses of COVID-19 vaccines. 23 (92%) patients required hospitalization. 20 (80%) patients survived and 6 (25%) required intensive care unit (ICU) admission. Among ICU patients, 66.7% were more than 50 years, 50% had two to three comorbidities and 5 out of 6 (83%) died. The mortality of transplant patients infected with Omicron variants in our cohort was higher than other centers as a limited number of patients received booster vaccines. Optimizing booster vaccination is the most efficient method to improve the mortality of COVID-19 in transplant recipients recognizing the inefficacy of monoclonal antibodies in the presence of SARS-CoV-2 emerging variants. We did not show a difference in mortality in transplant patients infected with Omicron BA.1 and BA.2 knowing the limitation of our sample size.

Humoral and cellular immune correlates of protection against COVID-19 in kidney transplant recipients

As solid organ transplant recipients are at high risk of severe COVID-19 and respond poorly to primary SARS-CoV-2 mRNA vaccination, they have been prioritized for booster vaccination. However, an immunological correlate of protection has not been identified in this vulnerable population. We conducted a prospective monocentric cohort study of 65 kidney transplant recipients who received 3 doses of BNT162b2 mRNA vaccine. Associations among breakthrough infection (BTI), vaccine responses, and patient characteristics were explored in 54 patients. Symptomatic COVID-19 was diagnosed in 32% of kidney transplant recipients during a period of 6 months after booster vaccination. During this period, SARS-CoV-2 delta and omicron were the dominant variants in the general population. Univariate Analyses identified the avidity of SARS-CoV-2 receptor binding domain binding IgG, neutralizing antibodies, and SARS-CoV-2 S2-specific interferon gamma responses as correlates of protection against BTI. No demographic or clinical parameter correlated with the risk of BTI. In multivariate analysis, the risk of BTI was best predicted by neutralizing antibody and S2-specific interferon gamma responses. In conclusion, T cell responses may help compensate for the suboptimal antibody response to booster vaccination in kidney transplant recipients. Further studies are needed to confirm these findings.

COVID-19 and Kidney Disease

COVID-19 can cause acute kidney injury and may cause or exacerbate chronic kidney diseases, including glomerular diseases. SARS-CoV-2 infection of kidney cells has been reported, but it remains unclear if viral infection of kidney cells causes disease. The most important causes of kidney injury in patients with COVID-19 include impaired renal perfusion and immune dysregulation. Chronic kidney disease, especially kidney failure with kidney replacement therapy and kidney transplant, is associated with markedly increased COVID-19 mortality. Persons with severe kidney disease have been excluded from most clinical trials of COVID-19 therapies, so therapeutic approaches must be extrapolated from studies of patients without kidney disease. Some medications used to treat COVID-19 should be avoided or used at reduced dosages in patients with severe kidney disease and in kidney transplant recipients. Additional research is needed to determine the optimal strategies to prevent and treat COVID-19 in patients with kidney disease.

The immunologically high-risk kidney recipient in the early post-COVID-19 period. To do or not to do? A case report

Kidney transplantation is nowadays the treatment of choice for end-stage kidney disease (ESKD), and it is the most performed organ transplantation. During the COVID-19 pandemic, kidney-transplant recipients appeared to be at higher risk of morbidity and mortality due to severe forms of illness. The result was a decrease in the number of solid organs transplants worldwide, with patients' reduced chance of receiving transplants. The best timing for surgery after COVID-19 infection is still controversial since most of the available data come from study periods with zero or low prevalence of vaccination and COVID-19 variants with high mortality rates. The American Society of Anesthesiologists (ASA) and the Anesthesia Patient Safety Foundation (APSF) Joint Statement on Elective Surgery/Procedures and Anesthesia for Patients after COVID-19 Infection states that elective surgery should be delayed for 7 weeks after a SARS-CoV-2 infection in unvaccinated patients while making no clear statement for vaccinated ones, or those which have already been infected with the virus. Kidney transplant, as opposed to tissue transplant, is not an elective surgery, so the question raised is whether to do it or not. We present the case of a hyper-immunized 47-year-old male patient with end-stage chronic kidney disease who received a second kidney transplant, despite having a mild SARS-COV 2 infection just 2 weeks before his transplantation surgery.

Seroconversion rates in kidney transplant recipients following SARS-CoV-2 vaccination and its association with immunosuppressive agents: a systematic review and meta-analysis

This systematic and meta-analysis aims to evaluate humoral and cellular responses to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine among kidney transplant recipients (KTRs). We conducted a systematic literature search across databases to evaluate seroconversion and cellular response rates in KTRs receiving SARS-CoV-2 vaccines. We extracted studies that assessed seroconversion rates described as the presence of antibody de novo positivity in KTRs following SARS-CoV-2 vaccination published up to January 23rd, 2022. We also performed meta-regression based on immunosuppression therapy used. A total of 44 studies involving 5,892 KTRs were included in this meta-analysis. The overall seroconversion rate following complete dose of vaccines was 39.2% (95% confidence interval [CI], 33.3%-45.3%) and cellular response rate was 41.6% (95% CI, 30.0%-53.6%). Meta-regression revealed that low antibody response rate was significantly associated with the high prevalence of mycophenolate mofetil/mycophenolic acid (p=0.04), belatacept (p=0.02), and anti-CD25 induction therapy uses (p=0.04). Conversely, tacrolimus use was associated with higher antibody response (p=0.01). This meta-analysis suggests that postvaccination seroconversion and cellular response rates in KTRs are still low. And seroconversion rate was correlated with the type of immunosuppressive agent and induction therapy used. Additional doses of the SARS-CoV-2 vaccine for this population using a different type of vaccine are considered.

Performance of Derived Laboratory Biomarkers with Regard to 30-Day Mortality in Kidney Transplant Recipients with COVID-19

There are limited data on the performance of laboratory-derived biomarkers in kidney transplant recipients (KTR) with COVID-19. This observational study enrolled 65 KTR with COVID-19 who were treated at the University Hospital of Split up to March 2022. Laboratory-derived biomarkers (neutrophile-to-lymphocyte (NLR) ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, De Ritis ratio, C-reactive protein (CRP)-to-albumin ratio, lactate dehydrogenase (LDH)-to-hemoglobin ratio, CRP-to-lymphocyte ratio, red cell distribution width-to-albumin ratio, platelet-to-albumin ratio, D-Dimer-to-albumin ratio, D-Dimer-to-NLR ratio, LDH-to-albumin ratio, and LDH-to-white blood cell (WBC) ratio) were calculated, and their performance with regard to 30-day mortality was determined. Mortality events occurred in 12 patients (18.5%), which was significantly associated with increased De Ritis (HR 3.83, 95% CI 1.57-9.35, p = 0.003), CRP-to-albumin (HR 1.36, 95% CI 1.13-1.64, p = 0.001), LDH-to-hemoglobin (HR 1.44, 95% CI 1.07-1.92, p = 0.015), CRP-to-lymphocyte (HR 1.03, 95% CI 1.01-1.07, p = 0.003), D-dimer-to-albumin (HR 4.94, 95% CI 1.38-7.24, p = 0.038), LDH-to-albumin (HR 1.20, 95% CI 1.05-1.36, p = 0.008), and LDH-to-WBC (HR 1.03 95% CI 1.01-1.05, p = 0.024) ratios. Out of these, the best area-under-the-curve (AUC) values were achieved with De Ritis (AUC 0.691), CRP-to-albumin (AUC 0.764), LDH-to-hemoglobin (AUC 0.877), CRP-to-lymphocyte (AUC 0.739), and LDH-to-albumin (AUC 0.827) ratios, while the best discrimination displayed LDH-to-hemoglobin ratio (Harrell's C 0.808 and Somers' D 0.616). The overall calibration was satisfactory for all models. Derived laboratory biomarkers such as the de Ritis, CRP-to-albumin, LDH-to-hemoglobin, CRP-to-lymphocyte, and LDH-to-albumin ratios show significant association and discrimination with all-cause mortality in KTR with COVID-19, suggesting its potential risk stratification role.

Pediatric kidney transplantation during the COVID-19 pandemic

A waiting list for non-emergency transplant medical care was recommended in the first half of 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. Hence, the number of kidney transplants temporarily declined. However, the waiting list for transplant medical care was lifted in the latter half of 2020 with the establishment of a polymerase chain reaction test system and the spread of infection prevention. The basic stance is to recommend vaccination to post-transplant recipients, recipients, and donors who are scheduled to undergo transplantation, and their families, with the start of vaccine therapy in 2021. The mortality rate of patients undergoing kidney transplants who had COVID-19 is slightly higher than healthy persons, and acute kidney injury was reported to lead to graft loss. However, pediatric cases of severe disease are rare and without deaths. Kidney transplantation medical care will be continuously provided by implementing infection prevention and treatments based on the latest evidence, promoting donated kidney transplantation, and hoping that pediatric patients with renal failure will grow up healthy, both physically and mentally, and become independent members of society, just like healthy children.

Absence of Mortality Differences Between the First and Second COVID-19 Waves in Kidney Transplant Recipients

Introduction

SARS-CoV-2 pandemic evolved in 2 consecutive waves during 2020. Improvements in the management of COVID-19 led to a reduction in mortality rates among hospitalized patients during the second wave. Whether this progress benefited kidney transplant recipients (KTRs), a population particularly vulnerable to severe COVID-19, remained unclear.

Methods

In France, 957 KTRs were hospitalized for COVID-19 in 2020 and their data were prospectively collected into the French Solid Organ Transplant (SOT) COVID registry. The presentation, management, and outcomes of the 359 KTRs diagnosed during the first wave were compared to those of the 598 of the second wave.

Results

Baseline comorbidities were similar between KTRs of the 2 waves. Maintenance immunosuppression was reduced in most patients but withdrawal of antimetabolite (73.7% vs. 58.4%, P < 0.001) or calcineurin inhibitor (32.1% vs. 16.6%, P < 0.001) was less frequent during the second wave. Hydroxychloroquine and azithromycin that were commonly used during the first wave (21.7% and 30.9%, respectively) but were almost abandoned during the second wave. In contrast, the use of high dose corticosteroids doubled (19.5% vs. 41.6%, P < 0.001). Despite these changing trends in COVID-19 management, 60-day mortality was not statistically different between the 2 waves (25.3% vs. 23.9%; Log Rank, P = 0.48) and COVID-19 hospitalization period was not associated with death due to COVID-19 in multivariate analysis (Hazard ratio 0.89, 95% confidence interval 0.67-1.17, P = 0.4).

Conclusion

We conclude that changing of therapeutic trends during 2020 did not reduce COVID-19 related mortality among KTRs. Our data indirectly support the importance of vaccination and neutralizing monoclonal anti-SARS-CoV-2 antibodies to protect KTRS from severe COVID-19.

Impact of Hypertension on COVID-19 Burden in Kidney Transplant Recipients: An Observational Cohort Study

BACKGROUND

COVID-19 severity is determined by cardiometabolic risk factors, which can be further aggravated by chronic immunosuppression in kidney transplant recipients (KTRs). We aimed to verify the main risk factors related to hypertension (HTN) that contribute to COVID-19 progression and mortality in that population.

METHODS

Retrospective analysis of 300 KTRs from March 2020 to August 2020 in a single center. We compared the main outcomes between HTN (n = 225) and non-HTN (n = 75), including admission to the intensive care unit (ICU), development of acute kidney injury (AKI), need for invasive mechanical ventilation or oxygen, and mortality.

RESULTS

Of the patients in the study, 57.3% were male, 61.3% were white, the mean age was 52.5 years, and 75% had HTN. Pre-existing HTN was independently associated with higher rates of mortality (32.9%, OR = 1.96, p = 0.036), transfer to the ICU (50.7%, OR = 1.94, p = 0.017), and AKI with hemodialysis (HD) requirement (40.4%, OR = 2.15, p = 0.011). In the hypertensive group, age, diabetes mellitus, heart disease, smoking, glycemic control before admission, C-reactive protein, lactate dehydrogenase, lymphocytes, and D-dimer were significantly associated with COVID-19 progression and mortality. Both lower basal and previous estimated glomerular filtration rates posed KTRs with HTN at greater risk for HD requirement.

CONCLUSIONS

Therefore, the early identification of factors that predict COVID-19 progression and mortality in KTRs affected by COVID-19 contributes to therapeutic decisions, patient flow management, and allocation of resources.

Determinants of Antibody Response to SARS-CoV-2 Vaccines in Liver Transplant Recipients: The Role of Immunosuppression Reduction

Liver transplant recipients on chronic immunosuppression show an attenuated antibody response after SARS-CoV-2 vaccination. Adjusting immunosuppressants during vaccination remains debated. We enrolled 380 liver transplant recipients receiving 2 doses of a protein subunit, mRNA, or a vector vaccine. The patients were informed to temporarily suspend immunosuppression for 2 weeks for both vaccination doses. We measured anti-live-SARS-CoV-2 spike neutralizing antibody levels at 1−2 months after the second vaccination; 83.9% of patients had humoral responses (SARS-CoV-2 NT50 ≥ 9.62 IU/mL) to 2 doses of vaccines. The mRNA (86.7%) and protein subunit vaccines (85%) yielded higher response rates than the vector vaccines (40.9%). Immunosuppression suspension during the two vaccinations yielded a higher response rate (91.5% vs. 57.7%). Only eight patients (2.1%) experienced transaminase level elevation of thrice the normal value (>110 IU/L) after the second vaccination. Most recovered spontaneously after resuming immunosuppression. Multivariate analysis revealed ABO incompatibility, white blood cell count <4000, lymphocyte count <20%, tacrolimus trough level >6.5 ng/mL, and no immunosuppression adjustment as independent risk factors to nonresponse. The mRNA and protein subunit vaccines yielded a higher response rate. Immunosuppression suspension for 2 weeks enhanced the antibody response. ABO incompatibility, leukopenia, lymphopenia, a high tacrolimus trough level, and no immunosuppression adjustment are associated with nonresponse.

Kidney health in the COVID-19 pandemic: An umbrella review of meta-analyses and systematic reviews

Background

This umbrella review aims to consolidate evidence from systematic reviews and meta-analyses investigating the impact of the coronavirus disease-2019 (COVID-19) on kidney health, and the associations between kidney diseases and clinical outcomes in COVID-19 patients.

Methods

Five databases, namely, EMBASE, PubMed, Web of Science, the Cochrane Database of Systematic Reviews and Ovid Medline, were searched for meta-analyses and systematic reviews from January 1, 2020 to June 2, 2022. Two reviewers independently selected reviews, identified reviews for inclusion and extracted data. Disagreements were resolved by group discussions. Two reviewers independently assessed the methodological quality of all included reviews using ROBIS tool. A narrative synthesis was conducted. The characteristics and major findings of the included reviews are presented using tables and forest plots. The included meta-analyses were updated when necessary. The review protocol was prospectively registered in PROSPERO (CRD42021266300).

Results

A total of 103 reviews were identified. Using ROBIS, 30 reviews were rated as low risk of bias. Data from these 30 reviews were included in the narrative synthesis. Ten meta-analyses were updated by incorporating 119 newly available cohort studies. Hospitalized COVID-19 patients had a notable acute kidney injury (AKI) incidence of 27.17%. AKI was significantly associated with mortality (pooled OR: 5.24) and severe conditions in COVID-19 patients (OR: 14.94). The pooled prevalence of CKD in COVID-19 patients was 5.7%. Pre-existing CKD was associated with a higher risk of death (pooled OR: 2.21) and disease severity (pooled OR: 1.87). Kidney transplant recipients were susceptible to SARS-CoV-2 infection (incidence: 23 per 10,000 person-weeks) with a pooled mortality of 18%.

Conclusion

Kidney disease such as CKD or recipients of kidney transplants were at increased risk of contracting COVID-19. Persons with COVID-19 also had a notable AKI incidence. AKI, the need for RRT, pre-existing CKD and a history of kidney transplantation are associated with adverse outcomes in COVID-19.

Systematic review registration

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021266300, identifier: CRD42021266300.

Risk factors for mortality in kidney transplant recipients with COVID-19: a single centre experience and case-control study

BACKGROUND

COVID-19 infection is considered to cause high mortality in kidney transplant recipients (KTR). Old age, comorbidities and acute kidney injury are known risk factors for increased mortality in KTR. Nevertheless, mortality rates have varied across different regions. Differences in age, comorbidities and varying standards of care across geographies may explain some variations. However, it is still unclear whether post-transplant duration, induction therapy, antirejection therapy and co-infections contribute to increased mortality in KTR with COVID-19. The present study assessed risk factors in a large cohort from India.

METHODS

A matched case-control study was performed to analyze risk factors for death in KTR (N = 218) diagnosed with COVID-19 between April 2020 to July 2021 at the study centre. Cases were KTR who died (non-survivors, N = 30), whereas those who survived were taken as controls (survivors, N = 188).

RESULTS

A high death-to-case ratio of 13.8% was observed amongst study group KTR infected with COVID-19. There was a high incidence (12.4%) of co-infections, with cytomegalovirus being the most common co-infection among non-survivors. Diarrhea, co-infection, high oxygen requirement, and need for mechanical ventilation were significantly associated with mortality on regression analyses. Antirejection therapy, lymphopenia and requirement for renal replacement therapy were associated with worse outcomes.

CONCLUSIONS

The mortality was much higher in KTR who required mechanical ventilation and had co-infections. Mortality did not vary with the type of transplant, post-transplant duration and usage of depletion induction therapy. An aggressive approach has to be taken for an early diagnosis and therapeutic intervention of associated infections.

The Global Impact of COVID-19 on Solid Organ Transplantation: Two Years Into a Pandemic

The coronavirus disease 2019 (COVID-19) pandemic has had a major global impact on solid organ transplantation (SOT). An estimated 16% global reduction in transplant activity occurred over the course of 2020, most markedly impacting kidney transplant and living donor programs, resulting in substantial knock-on effects for waitlisted patients. The increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection risk and excess deaths in transplant candidates has resulted in substantial effort to prioritize the safe restart and continuation of transplant programs over the second year of the pandemic, with transplant rates returning towards prepandemic levels. Over the past 2 y, COVID-19 mortality in SOT recipients has fallen from 20%-25% to 8%-10%, attributed to the increased and early availability of SARS-CoV-2 testing, adherence to nonpharmaceutical interventions, development of novel treatments, and vaccination. Despite these positive steps, transplant programs and SOT recipients continue to face challenges. Vaccine efficacy in SOT recipients is substantially lower than the general population and SOT recipients remain at an increased risk of adverse outcomes if they develop COVID-19. SOT recipients and transplant teams need to remain vigilant and ongoing adherence to nonpharmaceutical interventions appears essential. In this review, we summarize the global impact of COVID-19 on transplant activity, donor evaluation, and patient outcomes over the past 2 y, discuss the current strategies aimed at preventing and treating SARS-CoV-2 infection in SOT recipients, and based on lessons learnt from this pandemic, propose steps the transplant community could consider as preparation for future pandemics.

The Role of Registries in Kidney Transplantation Across International Boundaries

Transplant professionals strive to improve domestic kidney transplantation rates safely, cost efficiently, and ethically, but to increase rates further may wish to allow their recipients and donors to traverse international boundaries. Travel for transplantation presents significant challenges to the practice of transplantation medicine and donor medicine, but can be enhanced if sustainable international registries develop to include low- and low-middle income countries. Robust data collection and sharing across registries, linking pretransplant information to post-transplant information, linking donor to recipient information, increasing living donor transplant activity through paired exchange, and ongoing reporting of results to permit flexibility and adaptability to changing clinical environments, will all serve to enhance kidney transplantation across international boundaries.

COVID-19 and Kidney Disease: A Clinical Perspective

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome Coronavirus- 2 (SARS-CoV-2), has caused a global pandemic with high morbidity and mortality. The presence of several comorbidities has been associated with a worse prognosis, with chronic kidney disease being a critical risk factor. Regarding COVID-19 complications, other than classical pneumonia and thromboembolism, acute kidney injury (AKI) is highly prevalent and represents a poor prognostic indicator linked to increased disease severity and mortality. Its pathophysiology is multifactorial, revolving around inflammation, endothelial dysfunction, and activation of coagulation, while the direct viral insult of the kidney remains a matter of controversy. Indirectly, COVID-19 AKI may stem from sepsis, volume depletion, and administration of nephrotoxic agents, among others. Several markers have been proposed for the early detection of COVID-19 AKI, including blood and urinary inflammatory and kidney injury biomarkers, while urinary SARS-CoV-2 load may also be an early prognostic sign. Concerning renal replacement therapy (RRT), general principles apply to COVID-19 AKI, but sudden RRT surges may mandate adjustments in resources. Following an episode of COVID-19 AKI, there is a gradual recovery of kidney function, with pre-existing renal impairment and high serum creatinine at discharge being associated with kidney disease progression and long-term dialysis dependence. Finally, kidney transplant recipients represent a special patient category with increased susceptibility to COVID- 19 and subsequent high risk of severe disease progression. Rates of mortality, AKI, and graft rejection are significantly elevated in the presence of COVID-19, highlighting the need for prevention and careful management of the disease in this subgroup.

SARS-CoV-2 Infection of Unvaccinated Liver- and Kidney-Transplant Recipients: A Single-Center Experience of 103 Consecutive Cases

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) was declared a pandemic in March 2020. Its reported impact on solid-organ-transplant-recipient morbidity and mortality has varied. The aim of this study was to present the effect of transplant status, patient comorbidities and immunosuppression modality on the survival of solid-organ-transplant recipients who contracted SAR-CoV-2 during the pre-vaccination era, at a single academic transplant center. Patients (n = 103) were assessed for 90-day mortality. A univariate analysis identified an age of over 60 years (HR = 10, p = 0.0034), Belatacept (HR = 6.1, p = 0.022), and Cyclosporine (HR = 6.1, p = 0.0089) as significant mortality risk factors; Tacrolimus was protective (HR = 0.23, p = 0.022). Common metabolic comorbidities (hypertension, diabetes, obesity) did not stand out as risk factors in our patient cohort. This study on the unvaccinated is expected to facilitate a paired comparison of outcomes in transplanted patients who contracted SARS-CoV-2 during the latter period of the pandemic, when broad SARS-CoV-2 vaccination and novel antibody treatments became broadly available.

A Comprehensive Comparison of Clinical Presentation and Outcomes of Kidney Transplant Recipients with COVID-19 during Wave 1 versus Wave 2 at a Tertiary Care Center, India

Data comparing the clinical spectrum of COVID-19 in kidney transplant recipients (KTRs) during the first and second waves of the pandemic in India is limited. Our single-center retrospective study compared the clinical profile, mortality, and associated risk factors in KTRs with COVID-19 during the 1st wave (1^st February 2020 to 31^st January 2021) and the second wave (1^st March-31^st August 2021). 156 KTRs with PCR confirmed SARS-CoV-2 infection treated at a tertiary care hospital in New Delhi during the 1st and the second waves were analyzed. The demographics and baseline transplant characteristics of the patients diagnosed during both waves were comparable. Patients in the second wave reported less frequent hospitalization, though the intensive care unit (ICU) and ventilator requirements were similar. Strategies to modify immunosuppressants such as discontinuation of antinucleoside drugs with or without change in calcineurin inhibitors and the use of steroids were similar during both waves. Overall patient mortality was 27.5%. The demographics and baseline characteristics of survivors and nonsurvivors were comparable. A higher percentage of nonsurvivors presented with breathing difficulty, low SpO₂, and altered sensorium. Both wave risk factors for mortality included older age, severe disease, ICU/ventilator requirements, acute kidney injury (AKI) needing dialysis, Chest Computerized Tomographic (CT) scan abnormalities, and higher levels of inflammatory markers particularly D-dimer and interleukin-6 levels. Conclusions. KTRs in both COVID-19 waves had similar demographics and baseline characteristics, while fewer patients during the second wave required hospitalization. The D-dimer and IL-6 levels are directly correlated with mortality.

COVID-19 Vaccine Efficacy and Immunogenicity in End-Stage Renal Disease Patients and Kidney Transplant Recipients

Purpose of Review

To summarize the current literature with respect to COVID-19 vaccine efficacy patients with end-stage renal disease on dialysis and kidney transplant recipients.

Recent Findings

Immunosuppressed patients are at greater risk of morbidity and mortality from COVID-19 infection. Patients with ESRD and KTR are immunosuppressed and mount a weaker antibody response to COVID-19 mRNA vaccination, and factors including immunosuppressant medications have been implicated for this weakened response. Third and fourth doses of vaccine doses have been shown to increase seropositivity and antibody production in kidney transplant recipients and patients on dialysis. Retrospective studies have demonstrated decreased mortality in vaccinated, immunosuppressed patients.

Summary

ESRD and KTR patients have decreased antibody response to COVID-19 vaccines, but third and fourth doses have been shown to increase antibody production. Though a correlate of protection between antibody production and efficacy has yet to be fully established in this subset of the population, all US professional bodies who treat ESRD and KTR patients advocate for full vaccination against SARS-CoV-2 based on the data available. Studies demonstrating decreased mortality in vaccinated patients are promising on efficacy. Importantly, because KTR patients mount a weaker antibody response than ESRD patients, vaccination prior to kidney transplantation is critical.

High mortality of COVID-19 early after allogeneic stem cell transplantation – a retrospective multicenter analysis on behalf of the German Cooperative Transplant Study Group

Recipients of allogeneic stem cell transplantation (alloSCT) are at high risk for contracting infectious diseases with high morbidity and mortality. Coronavirus disease 2019 (COVID-19) is a viral respiratory disease that can lead to severe pneumonia and acute respiratory distress syndrome, with a potentially fatal outcome. In this retrospective study conducted on behalf of the German Cooperative Transplant Study Group, we aimed to analyze risk factors, disease course, and outcomes of COVID-19 in patients who underwent alloSCT. AlloSCT recipients who became infected with SARS-CoV-2 at German and Austrian transplant centers between February 2020 and July 2021 were included. Classification of COVID-19 severity into mild, moderate-severe, or critical disease and division of the course of the pandemic into 4 phases were done according to the German Robert Koch Institute. The main endpoint was overall mortality at the end of follow-up. We further analyzed the need for treatment in an intensive care unit (ICU) and the severity of disease. Risk factors were evaluated using univariate and multivariate analyses, and survival analysis was performed using Kaplan-Meier method. The study cohort comprised 130 patients from 14 transplant centers, with a median age at diagnosis of COVID-19 of 59 years (range, 20 to 81 years) and a median interval between alloSCT and COVID-19 of 787 days (range, 19 to 8138 days). The most common underlying diseases were acute myeloid leukemia (45.4%) and lymphoma (10.8%). The majority of patients (84.9%) were infected in the later phases of the pandemic; 20.8% had moderate-severe disease, 12.3% had critical disease, and 19.2% were treated in an ICU. After a median follow-up of 127 days, overall mortality was 16.2%, 52.0% among patients treated in an ICU. Risk factors for mortality in multivariate analysis were active disease (odds ratio [OR], 4.46), infection with SARS-CoV-2 ≤365 days after alloSCT (OR, 5.60), age >60 years (OR, 5.39), and ongoing immunosuppression with cyclosporine (OR, 8.55). Risk factors for developing moderate-severe or critical disease were concurrent immunosuppression (OR, 4.06) and age >40 years (OR, 4.08). Patients after alloSCT exhibit a substantially increased mortality risk after COVID-19 infection compared with the normal population, without considerable improvement over the course of the pandemic. Risk factors include age, early infection post-alloSCT, and active immunosuppression. Further studies are needed to improve prevention and treatment in this high-risk patient group.

Humoral Immunity of BBIBP-CorV (Sinopharm) in kidney transplant recipients: Is it time to revise vaccination strategies

BACKGROUND

The mortality of COVID-19 is high in transplant patients, and effective vaccination is aimed to reduce severe disease and mortality.

METHODS

We conducted a cross-sectional study to evaluate humoral and cellular response to two 4μg-doses of BBIBP-CorV vaccine in 100 kidney transplant recipients, using Anti-Spike IgG, Total Anti-RBD, Neutralizing Ab level (ELISA), and interferon-gamma release assay (IGRA).

RESULTS

Seroconversion was evaluated 85.84 ± 30.72 days after second dose. 58% of all and 43.05% infection-naïve participants have developed at least one of the tested antibodies. IGRA was positive in 30.7% of tested transplant recipients. 60% of the participants had either humoral or cellular response to COIVD-19. Only age was independently linked to seropositivity of any degree after vaccination (p<0.05). COVID-naïve patients older than 60 years developed significantly less neutralizing antibody. (p value: 0.011). Six patients developed mild COVID infection more than a month after 2^nd dose of vaccine (54.5 ± 20.8 days). No vaccine-related adverse effects were reported, except self-limited mild to moderate fever and injection site pain.

CONCLUSION

BBIBP-CorV vaccine can be used safely in kidney transplant recipient, although impaired cellular and humoral immunity necessitates adjustments in vaccination strategies, like higher (8μg-doses), forth booster dose, or boost with different platform vaccine. This article is protected by copyright. All rights reserved.

Association of the novel CROW-65 risk score and mortality in hospitalized kidney transplant recipients with COVID-19 : A retrospective observational study

BACKGROUND

Kidney transplant recipients (KTR) are a group of patients with heterogeneous risks for adverse outcomes with COVID-19, but risk stratification tools in this patient group are lacking.

METHODS AND PARTICIPANTS

This retrospective observational, hypothesis-generating study included 49 hospitalized adult KTR patients with COVID-19 at the University Hospital of Split (August 2020 to October 2021) and evaluated the performance of novel risk score CROW-65 (age, Charlson Comorbidity Index [CCI] lactate dehydrogenase to white blood cell [LDH:WBC] ratio, and respiratory rate oxygenation [ROX index]). The primary outcome of the study was 30-day postdischarge all-cause mortality.

RESULTS

A total of 8 fatal events (16.3%) occurred during the study follow-up. When comparing CROW-65 by survival status, it was significantly increased in patients with fatal event (P < 0.001). Using the Cox proportional hazards regression analysis, the CROW-65 risk score showed statistically significant association with mortality (HR 1.11, 95% CI 1.01-1.23, P = 0.027), while receiving operator characteristics (ROC) showed significant discrimination of all-cause mortality with an AUC of 0.85 (95% CI 0.72-0.94, P < 0.001), and satisfactory calibration (χ² 4.91, P = 0.555 and Harrell's C 0.835). Finally, survival Kaplan-Meier analysis confirmed significantly higher cumulative incidence of mortality with increasing risk score tertiles and curve separation after 13 days (P = 0.009).

CONCLUSION

A novel risk score CROW-65 showed significant association with all-cause mortality in KTR yielding important hypothesis-generating findings. Further powered studies should reassess the performance of CROW-65 risk score in this population, including predictability, calibration and discrimination.

Solid organ transplantations and COVID-19 disease

Tens of thousands of people worldwide became infected with severe acute respiratory syndrome coronavirus-2. Death rate in the general population is about 1%-6%, but this rate rises up to 15% in those with comorbidities. Recent publications showed that the clinical progression of this disease in organ recipients is more destructive, with a fatality rate of up to 14%-25%. We aimed to review the effect of the pandemic on various transplantation patients. Coronavirus disease 2019 (COVID-19) has not only interrupted the lives of waiting list patients’; it has also impacted transplantation strategies, transplant surgeries and broken donation chains. COVID-19 was directly and indirectly accountable for a 73% surplus in mortality of this population as compared to wait listed patients in earlier years. The impact of chronic immunosuppression on outcomes of COVID-19 remains unclear but understanding the immunological mechanisms related to the virus is critically important for the lifetime of transplantation and immune suppressed patients. It is hard to endorse changing anti-rejection therapy, as the existing data evaluation is not adequate to advise substituting tacrolimus with cyclosporine during severe COVID-19 disease.