The risk and consequences of breakthrough SARS-CoV-2 infection in solid organ transplant recipients relative to non-immunosuppressed controls

The Relative Risk of COVID-19 in Solid Organ Transplant Recipients Over Waves of the Pandemic

Solid organ transplant recipients (SOTR) are at increased risk from COVID-19. Over time, the absolute risk of adverse outcomes after COVID-19 has decreased in both the non-immunosuppressed/immunocompromised (non-ISC) general population, and amongst SOTR. Using the N3C, we examined the absolute risk of mortality, major adverse renal or cardiac events, and hospitalization after COVID-19 diagnosis amongst non-ISC and SOTR populations over five waves of the pandemic (Wave 1: Ancestral COVID; Wave 2: Alpha; Wave 3: Delta; Wave 4: Omicron; Wave 5: Omicron). Within each wave, we determined the relative risk of each outcome for SOTR versus the non-ISC population based on crude event rates, and then used multivariable cox proportional hazards models and logistic regression to determine the adjusted risk of each outcome based on SOT status. Throughout the pandemic, including during the Omicron wave (Wave 5), SOTR were at greater absolute risk for each outcome than non-ISC patients (p-values all <0.001). The adjusted risk of SOT status for each outcome was relatively stable over time (aHR 1.28-1.61 for mortality; aHR 1.31-1.47 for MACE; aHR 1.72-1.90 for MARCE; aHR 1.75-2.07 for AKI; and aOR 1.53-1.81 for hospitalization). Despite a reduction in the absolute risk of COVID-19 complications, the relative risk for SOTR versus the non-ISC population has not improved.

The prevalence of postacute sequelae of coronavirus disease 2019 in solid organ transplant recipients: Evaluation of risk in the National COVID Cohort Collaborative

Postacute sequelae after the coronavirus disease (COVID) of 2019 (PASC) is increasingly recognized, although data on solid organ transplant (SOT) recipients (SOTRs) are limited. Using the National COVID Cohort Collaborative, we performed 1:1 propensity score matching (PSM) of all adult SOTR and nonimmunosuppressed/immunocompromised (ISC) patients with acute COVID infection (August 1, 2021 to January 13, 2023) for a subsequent PASC diagnosis using International Classification of Diseases, 10th Revision, Clinical Modification codes. Multivariable logistic regression was used to examine not only the association of SOT status with PASC, but also other patient factors after stratifying by SOT status. Prior to PSM, there were 8769 SOT and 1 576 769 non-ISC patients with acute COVID infection. After PSM, 8756 SOTR and 8756 non-ISC patients were included; 2.2% of SOTR (n = 192) and 1.4% (n = 122) of non-ISC patients developed PASC (P value < .001). In the overall matched cohort, SOT was independently associated with PASC (adjusted odds ratio [aOR], 1.48; 95% confidence interval [CI], 1.09-2.01). Among SOTR, COVID infection severity (aOR, 11.6; 95% CI, 3.93-30.0 for severe vs mild disease), older age (aOR, 1.02; 95% CI, 1.01-1.03 per year), and mycophenolate mofetil use (aOR, 2.04; 95% CI, 1.38-3.05) were each independently associated with PASC. In non-ISC patients, only depression (aOR, 1.96; 95% CI, 1.24-3.07) and COVID infection severity were. In conclusion, PASC occurs more commonly in SOTR than in non-ISC patients, with differences in risk profiles based on SOT status.

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.

Efficacy and safety of COVID-19 vaccination in solid organ transplant recipients: A systematic review and network meta-analysis

The impact of COVID-19 vaccination on clinical outcomes in solid organ transplant (SOT) recipients remains unclear. This systematic review and network meta-analysis sought to assess the efficacy and safety of COVID-19 vaccination in SOT recipients. We searched 6 databases from inception to March 1, 2024 for randomized controlled trials (RCTs) and observational studies evaluating different COVID-19 vaccination strategies in SOT recipients. Based on patient-important outcomes, we performed frequentist random-effects pairwise meta-analyses and network meta-analyses, separating RCTs and nonrandomized evidence, and used the Grading of Recommendation, Assessment, Development, and Evaluation approach to assess our certainty in the evidence. We included 6 RCTs (N = 814) and 43 observational studies (N = 125 199). Overall, there is a paucity of randomized evidence evaluating COVID-19 vaccines in SOT recipients. The nonrandomized evidence evaluating COVID-19 vaccination strategies patient-important outcomes, including COVID-19 infection, mortality, hospitalization, ICU admission, and rejection, demonstrated low to very low certainty due to the included studies' risk of bias. Throughout the COVID-19 pandemic, clinicians and SOT recipients worked with minimal, very low-quality evidence in relation to COVID-19 vaccines in this population. In the instance of future public health emergencies, clinicians and researchers should collaborate closely with patient partners to ensure there is sufficient evidence in the transplant population on patient-important outcomes.

COVID-19 Vaccine in Lung and Liver Transplant Recipients Exceeds Expectations: An Italian Real-Life Experience on Immunogenicity and Clinical Efficacy of BNT162b2 Vaccine

This study assessed humoral and T cell-mediated immune responses to the BNT162b2 vaccine in orthotopic liver transplant (OLT) and lung transplant (LUT) recipients who received three doses of the vaccine from March 2021 at our institution. Serum samples were collected 60 days post-second and third dose to quantify antibodies against the spike region of SARS-CoV-2 while whole blood samples were collected to analyze the SARS-CoV-2-specific T-cell response using an IFN-γ ELISpot assay. We enrolled 244 OLT and 120 LUT recipients. The third dose increased antibody titres in OLT recipients (from a median value of 131 after the second dose to 5523 IU/mL, p < 0.001) and LUT recipients (from 14.8 to 1729 IU/mL, p < 0.001). T-cell response also increased in OLT recipients (from 8.5 to 23 IFN-γ SFU per 250,000 PBMC, p < 0.001) and LUT recipients (from 8 to 15 IFN-γ SFU per 250,000 PBMC, p < 0.001). A total of 128 breakthrough infections were observed: two (0.8%) OLT recipients were hospitalized due to COVID-19 and one died (0.4%); among LUT recipients, seven were hospitalized (5.8%) and two patients died (1.7%). In conclusion, the three-dose schedule of the BNT162b2 vaccine elicited both humoral and T cell-mediated responses in solid organ transplant recipients. The risk of severe COVID-19 post-vaccination was low in this population.

The Impact of Time between Booster Doses on Humoral Immune Response in Solid Organ Transplant Recipients Vaccinated with BNT162b2 Vaccines

As solid organ transplant (SOT) recipients remain at risk of severe outcomes after SARS-CoV-2 infections, vaccination continues to be an important preventive measure. In SOT recipients previously vaccinated with at least three doses of BNT162b2, we investigated humoral responses to BNT162b2 booster doses. Anti-SARS-CoV-2 receptor binding domain (RBD) immunoglobulin G (IgG) was measured using an in-house ELISA. Linear mixed models were fitted to investigate the change in the geometric mean concentration (GMC) of anti-SARS-CoV-2 RBD IgG after vaccination in participants with intervals of more or less than six months between the last two doses of vaccine. We included 107 SOT recipients vaccinated with a BNT162b2 vaccine. In participants with an interval of more than six months between the last two vaccine doses, we found a 1.34-fold change in GMC per month (95% CI 1.25-1.44), while we found a 1.09-fold change in GMC per month (95% CI 0.89-1.34) in participants with an interval of less than six months between the last two vaccine doses, resulting in a rate ratio of 0.82 (95% CI 0.66 to 1.01, p = 0.063). In conclusion, the administration of identical COVID-19 mRNA vaccine boosters within six months to SOT recipients may result in limited humoral immunogenicity of the last dose.

Clinical characteristics and outcomes of liver transplant recipients infected by Omicron during the opening up of the dynamic zero-coronavirus disease policy in China: A prospective, observational study

We analyzed the characteristics, risk factors, outcomes, and post-coronavirus disease 2019 (COVID-19) symptoms in liver transplant recipients in China's late 2022 COVID-19 wave. Recipients with COVID-19 were enrolled from December 1, 2022, to January 31, 2023, and followed up until May 31, 2023. Baseline and characteristic data were collected. A total of 930 recipients were included, with a vaccination rate (non-mRNA) of 40.0%. Among 726 (78.1%) recipients with COVID-19, 641 (88.3%) patients were treated at home, 81 (11.2%) patients required hospitalization in general wards, 4 (0.6%) patients required intensive care, and 1 (0.1%) patient died because of COVID-19. Severe acute respiratory syndrome coronavirus 2 infection was related to close contact with confirmed cases (P < .001) and the condition of end-stage kidney disease (P < .046). Older age, male sex, less vaccination, and hypertension were independent risk factors for hospitalization. Fatigue (36.9%) was the most common symptom post-COVID-19, followed by memory loss (35.7%) and sleep disturbance (23.9%). Two doses of vaccines had a protective effect against these post-COVID-19 symptoms (P < .05). During this Omicron outbreak, liver transplant recipients were susceptible to COVID-19, with frequent hospitalization but low mortality. Two doses of non-mRNA COVID-19 vaccines could protect against liver transplant recipient hospitalization and post-COVID-19 symptoms.

Updates in Kidney Transplantation From the 2022 Banff-Canadian Society of Transplantation Joint Meeting: Conference Report

Purpose of the Conference

The 2022 Banff-Canadian Society of Transplantation Meeting in Banff, Alberta, brought together transplant professionals to review new developments across various aspects of solid organ transplantation (SOT) in Canada.

Sources of Information

Presentations included consensus recommendations from expert-led forums; experiences with new procedures and legislation; reports from public health data repositories; original clinical and laboratory research; and industry updates regarding novel technologies. Speakers referenced articles and reports published in peer-reviewed journals and online, and unpublished data and preliminary findings.

Methods

All authors attended presentations in-person or virtually. Recordings of select presentations were available for later review. Summaries emphasize concepts indicated by speakers as new and clinically relevant.

Key Findings

The COVID-19 pandemic disproportionately affected solid organ transplant recipients (SOTRs), who experience worse outcomes of COVID-19 infection than the general population. Vaccinations demonstrate an attenuated immunological response in SOTRs yet provide meaningful protection. Monoclonal antibodies are effective for both passive immunization and treatment of COVID-19 in SOTRs. Infection control protocols have driven the development of virtual methods for clinical research, such as using home blood draws and virtual follow-up to evaluate vaccine efficacy in SOTRs; and patient care delivery, such as employing telerehabilitation post transplant. Access to living kidney donation is limited by various disincentives experienced by potential donors, which may be overcome by more efficient evaluations including a One-Day Living Kidney Donor Assessment Clinic. The International Donation and Transplantation Legislative and Policy Forum provided a means of establishing consensus guidance for organ donation and transplantation (ODT) program policy to standardize delivery across jurisdictions. The implementation of a deemed consent model for organ and tissue donation in Nova Scotia may provide insight as to whether this model indeed improves access to organs. Canada's Indigenous population experiences unique barriers to transplantation, prompting efforts for more inclusive ODT policy-making. The Pan-Canadian ODT Data and Performance Reporting System Project has defined performance quality indicators, of which iTransplant and other point-of-care software solutions may facilitate collection; however, these endeavors ultimately require information technology infrastructure that exceeds the capabilities of the existing Canadian Organ Replacement Register and Canadian Transplant Registry. Pig-to-human xenotransplantation requires genetic modification of pigs and xenoantibody testing in recipients but may yet prove viable. Serum cell-free DNA, urine biomarkers, and genetic markers offer an alternative to routine biopsy for identifying subclinical rejection. Modified perfusion temperatures and perfusion solutions with hydrogen sulfide donor compounds may improve organ preservation. Molecular compatibility tools provide another means of improving SOTR outcomes, and the Genome Canada Transplant Consortium has been examining important considerations of their implementation.

Limitations

We were unable to capture all presentations and topics at the meeting due to the sizable quantity and variety. Topics ultimately excluded from this summary include those in pathology including Banff Classification updates; those unique to extra-renal SOT; as well as numerous abstract and poster presentations, allied health provider forums, and business meetings. A portion of the material was presented by speakers prior to peer-review or publication.

Implications

The various conference presentations summarized in this report identify methods by which individual clinicians and provincial ODT programs may improve access, delivery, and quality of SOT care in Canada, while additionally identifying gaps in the literature that investigators are encouraged to pursue.

Susceptibility to SARS-CoV-2 Infection and Immune Responses to COVID-19 Vaccination Among Recipients of Solid Organ Transplants

Solid organ transplant recipients (SOTRs) are at high risk for infections including SARS-CoV-2, primarily due to use of immunosuppressive therapies that prevent organ rejection. Furthermore, these immunosuppressants are typically associated with suboptimal responses to vaccination. While COVID-19 vaccines have reduced the risk of COVID-19-related morbidity and mortality in SOTRs, breakthrough infection rates and death remain higher in this population compared with immunocompetent individuals. Approaches to enhancing response in SOTRs, such as through administration of additional doses and heterologous vaccination, have resulted in increased seroresponse and antibody levels. In this article, safety and immunogenicity of mRNA COVID-19 vaccines in SOTRs are explored by dose. Key considerations for clinical practice and the current vaccine recommendations for SOTRs are discussed within the context of the dynamic COVID-19 vaccination guideline landscape. A thorough understanding of these topics is essential for determining public health and vaccination strategies to help protect immunocompromised populations, including SOTRs.

SARS-CoV-2 spike-protein targeted serology test results and their association with subsequent COVID-19-related outcomes

Importance

In the absence of evidence of clinical utility, the United States' Centers for Disease Control and Prevention does not currently recommend the assessment of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike-protein antibody levels. Clinicians and their patients, especially immunocompromised patients, may benefit from an adjunctive objective clinical laboratory measure of risk, using SARS-CoV-2 serology.

Objective

The aim of this study is to estimate the association between SARS-CoV-2 spike-protein targeted antibody levels and clinically relevant outcomes overall and among clinically relevant subgroups, such as vaccine and immunocompetency statuses.

Design

A retrospective cohort study was conducted using laboratory-based data containing SARS-CoV-2 antibody testing results, as well as medical and pharmacy claim data. SARS-CoV-2 testing was performed by two large United States-based reference clinical laboratories, Labcorp® and Quest Diagnostics, and was linked to medical insurance claims, including vaccination receipt, through the HealthVerity Marketplace. Follow-up for outcomes began after each eligible individual's first SARS-CoV-2 semiquantitative spike-protein targeted antibody test, from 16 November 2020 to 30 December 2021.

Exposures

Exposure is defined as having SARS-CoV-2 spike-protein targeted antibody testing.

Main outcomes and measures

Study outcomes were SARS-CoV-2 infection and a serious composite outcome (hospitalization with an associated SARS-CoV-2 infection or all-cause death). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Propensity score matching was used for confounding covariate control.

Results

In total, 143,091 (73.2%) and 52,355 (26.8%) eligible individuals had detectable and non-detectable levels of SARS-CoV-2 spike-protein targeted antibodies, respectively. In the overall population, having detectable vs. non-detectable antibodies was associated with an estimated 44% relative reduction in SARS-CoV-2 subsequent infection risk (HR, 0.56; 95% CI 0.53-0.59) and an 80% relative reduction in the risk of serious composite outcomes (HR 0.20; 95% CI 0.15-0.26). Relative risk reductions were observed across subgroups, including among immunocompromised persons.

Conclusion and relevance

Individuals with detectable SARS-CoV-2 spike-protein targeted antibody levels had fewer associated subsequent SARS-CoV-2 infections and serious adverse clinical outcomes. Policymakers and clinicians may find SARS-CoV-2 spike-protein targeted serology testing to be a useful adjunct in counseling patients with non-detectable antibody levels about adverse risks and reinforcing appropriate actions to mitigate such risks.

Hormone replacement therapy and COVID-19 outcomes in solid organ transplant recipients compared with the general population

Exogenous estrogen is associated with reduced coronavirus disease (COVID) mortality in nonimmunosuppressed/immunocompromised (non-ISC) postmenopausal females. Here, we examined the association of estrogen or testosterone hormone replacement therapy (HRT) with COVID outcomes in solid organ transplant recipients (SOTRs) compared to non-ISC individuals, given known differences in sex-based risk in these populations. SOTRs ≥45 years old with COVID-19 between April 1, 2020 and July 31, 2022 were identified using the National COVID Cohort Collaborative. The association of HRT use in the last 24 months (exogenous systemic estrogens for females; testosterone for males) with major adverse renal or cardiac events in the 90 days post-COVID diagnosis and other secondary outcomes were examined using multivariable Cox proportional hazards models and logistic regression. We repeated these analyses in a non-ISC control group for comparison. Our study included 1135 SOTRs and 43 383 immunocompetent patients on HRT with COVID-19. In non-ISC, HRT use was associated with lower risk of major adverse renal or cardiac events (adjusted hazard ratio [aHR], 0.61; 95% confidence interval [CI], 0.57-0.65 for females; aHR, 0.70; 95% CI, 0.65-0.77 for males) and all secondary outcomes. In SOTR, HRT reduced the risk of acute kidney injury (aHR, 0.79; 95% CI, 0.63-0.98) and mortality (aHR, 0.49; 95% CI, 0.28-0.85) in males with COVID but not in females. The potentially modifying effects of immunosuppression on the benefits of HRT requires further investigation.

Protective Effect of Vaccine Doses and Antibody Titers Against SARS-CoV-2 Infection in Kidney Transplant Recipients

Patients undergoing kidney transplantation have a poor response to vaccination and a higher risk of disease progression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The effectiveness of vaccine doses and antibody titer tests against the mutant variant in these patients remains unclear. We retrospectively analyzed the risk of SARS-CoV-2 infection in a single medical center according to vaccine doses and immune responses before the outbreak. Among 622 kidney transplant patients, there were 77 patients without vaccination, 26 with one dose, 74 with two doses, 357 with three, and 88 with four doses. The vaccination status and infection rate proportion were similar to the general population. Patients undergoing more than three vaccinations had a lower risk of infection (odds ratio = 0.6527, 95% CI = 0.4324-0.9937) and hospitalization (odds ratio = 0.3161, 95% CI = 0.1311-0.7464). Antibody and cellular responses were measured in 181 patients after vaccination. Anti-spike protein antibody titer of more than 1,689.3 BAU/mL is protective against SARS-CoV-2 infection (odds ratio = 0.4136, 95% CI = 0.1800-0.9043). A cellular response by interferon-γ release assay was not correlated with the disease (odds ratio = 1.001, 95% CI = 0.9995-1.002). In conclusion, despite mutant strain, more than three doses of the first-generation vaccine and high antibody titers provided better protection against the omicron variant for a kidney transplant recipient.

Vaccines and therapeutics for immunocompromised patients with COVID-19

The COVID-19 pandemic has disproportionately impacted immunocompromised patients. This diverse group is at increased risk for impaired vaccine responses, progression to severe disease, prolonged hospitalizations and deaths. At particular risk are people with deficiencies in lymphocyte number or function such as transplant recipients and those with hematologic malignancies. Such patients' immune responses to vaccination and infection are frequently impaired leaving them more vulnerable to prolonged high viral loads and severe complications of COVID-19. Those in turn, have implications for disease progression and persistence, development of immune escape variants and transmission of infection. Data to guide vaccination and treatment approaches in immunocompromised people are generally lacking and extrapolated from other populations. The large clinical trials leading to authorisation and approval of SARS-CoV-2 vaccines and therapeutics included very few immunocompromised participants. While experience is accumulating, studies focused on the special circumstances of immunocompromised patients are needed to inform prevention and treatment approaches.

Characteristics and outcomes of SARS-CoV-2 breakthrough infections among double-vaccinated and triple-vaccinated patients with inflammatory rheumatic diseases

OBJECTIVE

To analyse the clinical profile of SARS-CoV-2 breakthrough infections in at least double-vaccinated patients with inflammatory rheumatic diseases (IRDs).

METHODS

Data from the physician-reported German COVID-19-IRD registry collected between February 2021 and July 2022 were analysed. SARS-CoV-2 cases were stratified according to patients' vaccination status as being not vaccinated, double-vaccinated or triple-vaccinated prior to SARS-CoV-2 infection and descriptively compared. Independent associations between demographic and disease features and outcome of breakthrough infections were estimated by multivariable logistic regression.

RESULTS

In total, 2314 cases were included in the analysis (unvaccinated n=923, double-vaccinated n=551, triple-vaccinated n=803, quadruple-vaccinated n=37). SARS-CoV-2 infections occurred after a median of 151 (range 14-347) days in patients being double-vaccinated, and after 88 (range 14-270) days in those with a third vaccination. Hospitalisation was required in 15% of unvaccinated, 8% of double-vaccinated and 3% of triple-vaccinated/quadruple-vaccinated patients (p<0.001). Mortality was 2% in unvaccinated, 1.8% in the double-vaccinated and 0.6% in triple-vaccinated patients. Compared with unvaccinated patients, double-vaccinated (OR 0.43, 95% CI 0.29 to 0.62) and triple-vaccinated (OR 0.13, 95% CI 0.08 to 0.21) patients showed a significant lower risk of COVID-19-related hospitalisation. Using multivariable analysis, the third vaccination was significantly associated with a lower risk for COVID-19-related death (OR 0.26; 95% CI 0.01 to 0.73).

CONCLUSIONS

Our cross-sectional data of COVID-19 infections in patients with IRD showed a significant reduction of hospitalisation due to infection in double-vaccinated or triple-vaccinated patients compared with those without vaccination and even a significant reduction of COVID-19-related deaths in triple-vaccinated patients. These data strongly support the beneficial effect of COVID-19 vaccination in patients with IRD.

TRIAL REGISTRATION NUMBER

EuDRACT 2020-001958-21.

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.

A Pilot Single-Blinded, Randomized, Controlled Trial Comparing BNT162b2 vs. JNJ-78436735 Vaccine as the Third Dose After Two Doses of BNT162b2 Vaccine in Solid Organ Transplant Recipients

Solid Organ Transplant (SOT) recipients are at significant higher risk for COVID-19 and due to immunosuppressive medication, the immunogenicity after vaccination is suboptimal. In the previous studies, booster method showed significant benefit in this population. In the current study, we compared using a mix-and-match method vs. same vaccine as a third dose in SOT recipients. This was a patient-blinded, single center, randomized controlled trial comparing BNT162b2 vs. JNJ-78436735 vaccine as the third dose after two doses of BNT162b2 vaccine. We included adult SOT recipients with functional graft who had received two doses of BNT162b2 vaccine. Participants were randomly assigned to receive either BNT162b2 or JNJ-78436735 in one-to-one ratio. Primary outcome was SARS-CoV-2 IgG positivity at 1 month after the third dose. Sixty SOT recipients, including 36 kidney, 12 liver, 2 lung, 3 heart, and 5 combined transplants, were enrolled, and 57 recipients were analyzed per protocol. There were no statistically significant differences between the two vaccine protocols for IgG positivity (83.3% vs. 85.2% for BNT162b2 and JNJ-78436735, respectively, p = 0.85, Odds Ratio 0.95, 95% Confidence Interval 0.23-4.00). Comparison of the geometric mean titer demonstrated a higher trend with BNT162b2 (p = 0.09). In this pilot randomized controlled trial comparing mix and match method vs. uniform vaccination in SOT recipients, both vaccines were safely used. Since this was a small sample sized study, there was no statistically significant difference in immunogenicity; though, the mix and match method showed relatively lower geometric mean titer, as compared to uniform vaccine. Further studies need to be conducted to determine duration of this immunogenicity. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT05047640?term=20210641&draw=2&rank=1, identifier 20210641.

Omicron infections profile and vaccination status among 1881 liver transplant recipients: a multi-center retrospective cohort

BACKGROUND & AIMS

A wave of Omicron infections rapidly emerged in China in 2022, but large-scale data concerning the safety profile of vaccines and Coronavirus disease 2019 (COVID-19) infection features in liver transplant (LT) recipients have not been collected. Therefore, the aim of this study was to assess the protectiveness and safety profile of the inactivated vaccines in LT patients against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infections.

METHODS

A multi-center retrospective study was conducted in a cohort with a history of liver transplantation. Electronic questionnaires were used to collect data on demographics, vaccination information, history of liver transplantation, and characteristics of COVID-19 infection until June 2022. The vaccine information included number of doses, vaccine type, injection time, and adverse events.

RESULTS

A total of 1881 participants (487 vaccinated and 1394 unvaccinated patients) were enrolled from seven centers in China. Fourteen of the participants were infected by Omicron, and 50% patients had over 14 days of viral shedding duration. The protection rate of COVID-19 vaccinations to Omicron was 2.59%. The three breakthrough infections occurred more than 6 months after fully vaccinated. A total of 96 (19.7%) vaccinated patients had adverse events, including fatigue, myalgia, liver dysfunction, swelling, and scleroma. There were more Grade 3 adverse events in the preoperative vaccination group than those in the postoperative vaccination group.

CONCLUSION

Inactivated whole-virion SARS-CoV-2 vaccines are safe in patients with post-liver transplantation. The efficacy of inactivated vaccines decreases after 6 months of vaccination, it is recommended that liver transplant patients get boosted vaccinations as early as possible even when they are fully vaccinated. Although clinical manifestations of Omicron infections were mild in LT patients, unvaccinated patients might have a higher risk of liver dysfunction during infections.