Predictive Factors for Humoral Response After 2-dose SARS-CoV-2 Vaccine in Solid Organ Transplant Patients

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.

Bringing optimised COVID-19 vaccine schedules to immunocompromised populations (BOOST-IC): study protocol for an adaptive randomised controlled clinical trial

BACKGROUND

Immunocompromised hosts (ICH) experience more breakthrough infections and worse clinical outcomes following infection with COVID-19 than immunocompetent people. Prophylactic monoclonal antibody therapies can be challenging to access, and escape variants emerge rapidly. Immunity conferred through vaccination remains a central prevention strategy for COVID-19. COVID-19 vaccines do not elicit optimal immunity in ICH but boosting, through additional doses of vaccine improves humoral and cellular immune responses. This trial aims to assess the immunogenicity and safety of different COVID-19 vaccine booster strategies against SARS-CoV-2 for ICH in Australia.

METHODS

Bringing optimised COVID-19 vaccine schedules to immunocompromised populations (BOOST-IC) is an adaptive randomised trial of one or two additional doses of COVID-19 vaccines 3 months apart in people living with HIV, solid organ transplant (SOT) recipients, or those who have haematological malignancies (chronic lymphocytic leukaemia, non-Hodgkin lymphoma or multiple myeloma). Key eligibility criteria include having received 3 to 7 doses of Australian Therapeutic Goods Administration (TGA)-approved COVID-19 vaccines at least 3 months earlier, and having not received SARS-CoV-2-specific monoclonal antibodies in the 3 months prior to receiving the study vaccine. The primary outcome is the geometric mean concentration of anti-spike SARS-CoV-2 immunoglobulin G (IgG) 28 days after the final dose of the study vaccine. Key secondary outcomes include anti-spike SARS-CoV-2 IgG titres and the proportion of people seroconverting 6 and 12 months after study vaccines, local and systemic reactions in the 7 days after vaccination, adverse events of special interest, COVID-19 infection, mortality and quality of life.

DISCUSSION

This study will enhance the understanding of COVID-19 vaccine responses in ICH, and enable the development of safe, and optimised vaccine schedules in people with HIV, SOT, or haematological malignancy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05556720. Registered on 23rd August 2022.

Evaluation of Humoral Response following SARS-CoV-2 mRNA-Based Vaccination in Liver Transplant Recipients Receiving Tailored Immunosuppressive Therapy

Background: The role of tailored immunosuppression (IS) in the development of the humoral response (HR) to SARS-CoV-2 mRNA-based vaccination in liver transplant (LT) recipients is unknown. Methods: This is a single-centre prospective study of patients who underwent LT between January 2015 and December 2021 and who have received three doses of mRNA-based SARS-CoV-2 vaccination. Patients undergoing Tacrolimus-based immunosuppression (TAC-IS) were compared with those undergoing Everolimus-based immunosuppression (EVR-IS). Patients receiving the TAC-EVR combination were divided into two groups based on trough TAC concentrations, i.e., above or below 5 ng/mL. HR (analysed with ECLIA) was assessed at 30 to 135 days after vaccination. The primary outcome was the presence of a positive antibody titre (≥0.8 U/mL). Secondary outcomes were the presence of a highly protective antibody titre (≥142 U/mL), median antibody titre, and incidence of COVID-19. Results: Sixty-one participants were included. Twenty-four (40%) were receiving TAC-IS and thirty-seven (60%) were receiving EVR-IS. At the median follow-up of 116 (range: 89-154) days, there were no significant differences in positive antibody titre (95.8% vs. 94.6%; p = 0.8269), highly-protective antibody titre (83.3% vs. 81.1%; p = 0.8231), median antibody titre (2410 [IQ range 350-2500] vs. 1670 [IQ range 380-2500]; p = 0.9450), and COVID-19 incidence (0% vs. 5.4%; p = 0.5148). High serum creatinine and low estimated glomerular filtration rate were risk factors for a weak or absent HR. Conclusions: Three doses of mRNA-based SARS-CoV-2 vaccination yielded a highly protective HR in LT recipients. The use of TAC or EVR-based IS does not appear to influence HR or antibody titre, while renal disease is a risk factor for a weak or null HR.

Seroconversion after SARS-CoV-2 vaccination is protective against severe COVID-19 disease in heart transplant recipients

BACKGROUND

Heart transplant (HTX) recipients are prone to develop complications after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Vaccination is often ineffective due to weaker immunogenicity. In this high-volume single-center study, we aimed to determine factors influencing seroconversion after vaccination and predictors of severe SARS-CoV-2 infection.

METHODS

Two hundred twenty-nine HTX recipients were enrolled. Type of the first two vaccine doses included messenger RNA (mRNA), vector, and inactivated vaccines. We carried out analyses on seroconversion after the second and third doses of vaccination and on severity of infection. Antispike protein SARS-CoV-2 immunoglobulin G (IgG) was measured after the second and third vaccines and serostatus was defined. Effect of the first two vaccine doses was studied on patients who did not suffer SARS-CoV-2 infection before antibody measurement (n = 175). The effectivity of the third vaccine was evaluated among seronegative recipients after the second vaccine (n = 53). Predictors for severe infection defined as pneumonia, hospitalization or death were assessed in all patients who contracted SARS-CoV-2 infection (n = 92).

RESULTS

62% of the recipients became seropositive after the second vaccination. Longer time between HTX and vaccination (odds ratio [OR]: 2.35) and mRNA vaccine (OR: 4.83) were predictors of seroconversion. 58% of the nonresponsive patients became seropositive after receiving the third vaccine. Male sex increased the chance of IgG production after the third dose (OR: 5.65). Clinical course of SARS-CoV-2 infection was severe in 32%. Of all parameters assessed, only seropositivity before infection was proven to have a protective effect against severe infection (OR: 0.11).

CONCLUSIONS

We found that longer time since HTX, mRNA vaccine type, and male sex promoted seroconversion after SARS-CoV-2 vaccination in HTX recipients. Seropositivity-but not the number of vaccine doses-seemed to be protective against severe SARS-CoV-2 infection. Screening of HTX patients for anti-SARS-COV-2 antibodies may help to identify patients at risk for severe infection.

The impact of frailty syndrome on humoral response to SARS-CoV-2 mRNA vaccines in older kidney transplant recipients

PURPOSE

Advanced age is associated with an impaired humoral immune response to SARS-CoV-2 mRNA vaccination in kidney transplant recipients (KTR). The mechanisms are, however, poorly understood. Frailty syndrome assessment may determine the most vulnerable population.

METHODS

This study is a secondary analysis of a prospective study (NCT04832841) regarding seroconversion after BNT162b2 vaccination, including 101 SARS-CoV-2 naïve KTR 70 years and older. The Fried frailty components were evaluated, and antibodies against S1 and S2 subunits of SARS-CoV-2 were examined > 14 days after the second dose of BNT162b2 vaccine.

RESULTS

Seroconversion was observed in 33 KTR. Male gender, eGFR, MMF-free immunosuppression, and a lower frailty score were associated with higher seroconversion rates in univariable regression. Concerning frailty components, physical inactivity had the most negative effect on seroconversion (OR = 0.36, 95% CI 0.14-0.95, p = 0.039). In a multivariable regression adjusted for eGFR, MMF-free immunosuppression, time from transplant and gender, pre-frail (OR = 0.27, 95% CI 0.07-1.00, p = 0.050), and frail status (OR = 0.14, 95% CI 0.03-0.73, p = 0.019) were associated with an increased risk of unresponsiveness to SARS-CoV-2 vaccines.

CONCLUSION

Frailty was associated with an impaired humoral response to SARS-CoV-2 mRNA vaccination in older SARS-CoV-2 naïve KTR.

TRAIL REGISTRATION

This study is registered under the identifier NCT04832841 on ClinicalTrials.gov.

Low switched memory B cells are associated with no humoral response after SARS-CoV-2 vaccine boosters in kidney transplant recipients

Introduction

The humoral response after SARS-CoV-2 vaccination and boosters in kidney transplant recipients (KTRs) is heterogeneous and depends on immunosuppression status. There is no validated immune measurement associated with serological response in clinical practice. Multicolor flow cytometric immunophenotyping could be useful for measuring immune response. This study aimed to study B- and T-cell compartments through Standardized EuroFlow PID Orientation after SARS-CoV-2 vaccination and their association with IgG SARS-CoV-2 seropositivity status after two doses or boosters.

Methods

We conducted a multicenter prospective study to evaluate humoral response after SARS-CoV-2 vaccination in KTRs. Heterologous regimen: two doses of inactivated SARS-CoV-2 and two boosters of BNT162b2 mRNA (n=75). Homologous vaccination: two doses of BNT162b2 mRNA and one BNT162b2 mRNA booster (n=13). Booster doses were administrated to KTRs without taking into account their IgG SARS-CoV-2 seropositivity status. Peripheral blood samples were collected 30 days after the second dose and after the last heterologous or homologous booster. A standardized EuroFlow PID Orientation Tube (PIDOT) and a supervised automated analysis were used for immune monitoring cellular subsets after boosters.

Results

A total of 88 KTRs were included and divided into three groups according to the time of the first detected IgG SARS-CoV-2 seropositivity: non-responders (NRs, n=23), booster responders (BRs, n=41), and two-dose responders (2DRs, n=24). The NR group was more frequent on mycophenolate than the responder groups (NRs, 96%; BRs, 80%; 2DRs, 42%; p=0.000). Switched memory B cells in the 2DR group were higher than those in the BR and NR groups (medians of 30, 17, and 10 cells/ul, respectively; p=0.017). Additionally, the absolute count of central memory/terminal memory CD8 T cells was higher in the 2DR group than in the BR and NR groups. (166, 98, and 93 cells/ul, respectively; p=0.041). The rest of the T-cell populations studied did not show a statistical difference.

Conclusion

switched memory B cells and memory CD8 T-cell populations in peripheral blood were associated with the magnitude of the humoral response after SARS-CoV-2 vaccination. Boosters increased IgG anti-SARS-CoV-2 levels, CM/TM CD8 T cells, and switched MBCs in patients with seropositivity after two doses. Interestingly, no seropositivity after boosters was associated with the use of mycophenolate and a lower number of switched MBCs and CM/TM CD8 T cells in peripheral blood.

Factors influencing immunogenicity and safety of SARS-CoV-2 vaccine in liver transplantation recipients: a systematic review and meta-analysis

Background

This review summarizes the factors influencing the efficacy and safety of the COVID-19 vaccine in LTR through meta-analysis, hoping to provide strategies for vaccine use.

Methods

Electronic databases were screened for studies on mRNA vaccines in LTR. The primary outcome was the pooled seroconversion rate, and the secondary outcome was the incidence of adverse events+breakthrough infections. Subgroup analyses were made based on BMI, associated comorbidities, presence of baseline leukopenia, time since transplant, and drugs used.

Result

In total, 31 articles got included. The pooled seroconversion rate after at least two doses of SARS-CoV-2 vaccination was 72% (95% CI [0.52-0.91). With significant heterogeneity among studies I2 = 99.9%, the seroconversion rate was about 72% (95%CI [0.66-0.75]), from the studies reporting two doses of vaccine slightly higher around 75%(95%CI [0.29-1.22]) from studies reporting three doses. The pooled seroconversion rate within the lower to normal BMI group was 74% (95% CI [0.22-1.27], Pi=0.005) against 67% (95% CI [0.52-0.81], Pi=0.000) in the high BMI group. The pooled seroconversion rate in the ''positive leukopenia'' group was the lowest, 59%. Leukopenia could influence the vaccine seroconversion rate in LTR. From the time since transplant analysis after setting seven years as cut off point, the pooled seroconversion rate after at least two doses of COVID-19 vaccination was 53% (95% CI [0.18-0.83], P=0.003, I2 = 99.6%) in <7years group and 83% (95% CI [0.76-0.90], P=0.000 I2 = 95.7%) in > 7years group. The only time since transplantation had reached statistical significance to be considered a risk factor predictor of poor serological response (OR=1.27 95%CI [1.03-1.55], P=0.024). The breakthrough infection rate after vaccination was very low2% (95% CI 0.01-0.03, I2 = 63.0%), and the overall incidence of adverse events, which included mainly pain at the injection site and fatigue, was 18% (95%CI [0.11-0.25], I2 = 98.6%, Pi=0.000).

Conclusion

The seroconversion rate in LTR vaccinated with at least two doses of mRNA COVID-19 vaccine could be significantly affected by the vaccine type, immunosuppressant used, BMI, leukopenia, associated comorbidities, and time since transplantation. Nevertheless, booster doses are still recommended for LTR.

Factors That Predict a Sustained Humoral Response to COVID-19 Vaccines in Kidney Transplant Recipients

INTRODUCTION

Kidney transplant recipients (KTRs) produce a weak humoral response to coronavirus disease 2019 (COVID-19) vaccines. However, the factors associated with the quality of the serological response to three doses of COVID-19 vaccine have not been unambiguously identified.

METHODS

We included KTRs followed in the Nephrology Department at Amiens University Hospital (Amiens, France) between June and December 2021 who had received three doses of a COVID-19 mRNA vaccine (or two doses plus an episode of polymerase chain reaction-confirmed COVID-19). The lack of a humoral response was defined as an antibody titer below 7.1 binding antibody units (BAU)/mL, and an optimal response was defined as an antibody titer above 264 BAU/mL.

RESULTS

Of the 371 patients included, 246 (66.3%) were seropositive, and 97 (26.1%) had an optimal response. In a multivariate analysis, the only factor associated with seropositivity was a history of COVID-19 [odds ratio (OR) 87.2; 95% confidence interval (CI) (7.88-965.0); p < 0.0001], while the main factors associated with non-response were female sex [OR 0.28; 95%CI (0.15-0.51); p < 0.0001], less than 36 months between kidney transplantation and vaccination [OR 0.26; 95%CI (0.13-0.52); p < 0.0001], a higher creatinine level [OR 0.33; 95%CI (0.19-0.56); p < 0.0001], the use of tacrolimus [OR 0.23; 95%CI (0.12-0.45); p < 0.0001], the use of belatacept [OR 0.01; 95%CI (0.001-0.20); p = 0.002] and three-drug immunosuppression [OR 0.39; 95%CI (0.19-0.78); p = 0.015]. A history of COVID-19 was associated with an optimal response [OR 4.03; 95%CI (2.09-7.79); p < 0.0001], while an older age at vaccination [OR 0.97; 95%CI (0.95-0.99); p = 0.002], less than 36 months between kidney transplantation and vaccination [OR 0.35; 95%CI (0.18-0.69); p = 0.002], a higher creatinine level [OR 0.60; 95%CI (0.38-0.93); p = 0.02], three-drug immunosuppression [OR 0.45; 95%CI (0.27-0.76); p = 0.003] were associated with a poorer response.

CONCLUSION

We identified factors associated with a humoral response to a COVID-19 mRNA vaccine in KTRs. These findings might help physicians to optimize vaccination in KTRs.

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.

Response of antibody titers to SARS-CoV-2 vaccination and clinical outcomes during the predominance of the Omicron variant in Colombia

Introduction

The response to vaccination against the virus that causes severe acute respiratory infection syndrome coronavirus 2 is lower in renal transplant recipients than in the general population. The data obtained from Latin America showed reduced immunogenicity under inactivated virus vaccination schedules and messenger ribonucleic acid platforms.

Methods

A retrospective cohort study including renal transplant recipients from Colombia with a two-dose vaccination schedule against severe acute respiratory infection syndrome coronavirus 2 with Pfizer, AstraZeneca, Moderna, Jansen, and Sinovac vaccines between March 1, 2021 and December 1, 2021, was carried out with a follow-up period to evaluate outcomes until May 2022. The outcomes correspond to the titers of immunoglobulin G antibodies against the receptor binding domain of the severe acute respiratory infection syndrome coronavirus 2 spike and a composite outcome of mortality, general, and intensive care unit hospitalization.

Results

In total, 215 renal transplant recipients with two doses of vaccination for severe acute respiratory infection syndrome coronavirus 2 during the predominance of the Omicron variant in Colombia were included, with the measurement of immunoglobulin G antibody titers against the receptor binding domain of the severe acute respiratory infection syndrome coronavirus 2 spike at 8 weeks of vaccination. The mean age was 52.1 years, and the standard deviation was ± 14.2; severe acute respiratory infection syndrome coronavirus 2 infection occurred in 20% of the population, of which 23.26% required hospitalization, 13.95% were under intensive care unit management, and four cases of mortality (9.3%) were reported. Of the total population, 52.5% had antibody titers higher than 0.8 IU/mL (median 0.77 IU/mL, interquartile range 0.4-131). Patients with severe acute respiratory infection syndrome coronavirus 2 infection had a median antibody titer of 0.4 IU/mL (interquartile range 0.4-3.45), and those without infection had a median antibody titer of 1.8 IU/mL (interquartile range 0.4-202) (p = 0.015).

Conclusion

Anti-severe acute respiratory infection syndrome coronavirus 2 antibody titers with a cutoff point less than 0.8 IU/mL are associated with increased risk of severe acute respiratory infection syndrome coronavirus 2 infection.

Mycophenolic Acid Exposure Determines Antibody Formation Following SARS-CoV-2 Vaccination in Kidney Transplant Recipients: A Nested Cohort Study

Despite (repeated) boosting, kidney transplant recipients (KTRs) may remain at increased risk of severe COVID-19 since a substantial number of individuals remain seronegative or with low antibody titers. In particular, mycophenolic acid use has been shown to affect antibody formation negatively and may be an important modifiable risk factor. We investigated the exposure-response relationship between mycophenolic acid 12-hour area under the curve (AUC_0-12h ) exposure and seroconversion including antibody titers after vaccination using mRNA-1273 SARS-CoV-2 vaccine (Moderna) in 316 KTRs from our center that participated in the national Dutch renal patients COVID-19 vaccination - long term efficacy and safety of SARS-CoV-2 vaccination in kidney disease patients vaccination study. After two vaccination doses, 162 (51%) KTRs seroconverted. KTRs treated with mycophenolic acid showed less seroconversion and lower antibody titers compared with KTRs without mycophenolic acid (44% vs. 77%, and 36 binding antibody units (BAU)/mL vs. 340 BAU/mL; P < 0.001). The mean mycophenolic acid AUC_0-12h exposure was significantly lower in KTRs who seroconverted compared with KTRs who did not (39 vs. 29 mg⋅h/L; P < 0.001). High mycophenolic acid exposure (±90 mg⋅h/L) and no exposure to mycophenolic acid resulted in a seroconversion rate ranging from 10% to 80%. Every 10 mg⋅h/L increase in mycophenolic acid AUC_0-12h gave an adjusted odds ratio for seroconversion of 0.87 (95% confidence interval (CI), 0.79-0.97; P = 0.010) and 0.89 (95% CI, 0.85-0.93; P < 0.001) for KTRs on dual and triple maintenance immunosuppressive therapy, respectively. Higher mycophenolic acid AUC_0-12h correlated with lower antibody titers (R = 0.44, P < 0.001). This study demonstrates the exposure-response relationship between gold standard mycophenolic acid exposure and antibody formation to support interventional studies investigating mycophenolic acid adjustment to improve antibody formation after further boosting.

Immunity against Delta and Omicron variants elicited by homologous inactivated vaccine booster in kidney transplant recipients

Background

A third mRNA vaccine booster is recommended to improve immunity against SARS-CoV-2 in kidney transplant recipients (KTRs). However, the immunity against SARS-CoV-2 Ancestral strain and Delta and Omicron variants elicited by the third dose of inactivated booster vaccine in KTRs remains unknown.

Methods

The blood parameters related to blood cells count, hepatic function, kidney function, heart injury and immunity were explored clinically from laboratory examinations. SARS-CoV-2 specific antibody IgG titer was detected using an enzyme-linked immunosorbent assay. Cellular immunity was analyzed using interferon-γ enzyme-linked immunospot assay.

Results

The results showed that there were no severe adverse effects and apparent changes of clinical laboratory biomarkers in KTRs and healthy volunteers (HVs) after homologous inactivated vaccine booster. A third dose of inactivated vaccine booster significantly increased anti-Ancestral-spike-trimer-IgG and anti-Ancestral-receptor binding domain (RBD)-IgG titers in KTRs and HVs compared with the second vaccination. However, the anti-Delta-RBD-IgG and anti-Omicron-RBD-IgG titers were significantly lower than anti-Ancestral-RBD-IgG titer in KTRs and HVs after the third dose. Notably, only 25.6% (10/39) and 10.3% (4/39) of KTRs had seropositivity for anti-Delta-RBD-IgG and anti-Omicron-RBD-IgG after booster, which were significantly lower than HVs (anti-Delta-RBD-IgG: 100%, anti-Omicron-RBD-IgG: 77.8%). Ancestral strain nucleocapsid protein and spike specific T cell frequency after booster was not significantly increased in KTRs compared with the second dose, significantly lower than that in HVs. Moreover, 33.3% (12/36), 14.3% (3/21) and 14.3% (3/21) of KTRs were positive for the Ancestral strain and Delta and Omicron spike-specific T cells, which were significantly lower than HVs (Ancestral: 80.8%, Delta: 53.8%, and Omicron: 57.7%).

Conclusions

A third dose of inactivated booster vaccine may significantly increase humoral immunity against the Ancestral strain in KTRs, while humoral and cellular immunity against the Delta and Omicron variants were still poor in KTRs.

Immunogenicity and safety of SARS-CoV-2 mRNA vaccine in patients with nephrotic syndrome receiving immunosuppressive agents

BACKGROUND

As there are no large-scale reports of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mRNA vaccination in patients with nephrotic syndrome using immunosuppressive agents, we conducted the prospective study.

METHODS

SARS-CoV-2 mRNA vaccines were administered to patients with nephrotic syndrome receiving immunosuppressive agents. The titers of SARS-CoV-2 spike protein receptor-binding domain antibodies were measured before and after vaccination. We evaluated factors associated with antibody titers after vaccination and analyzed adverse events.

RESULTS

We enrolled 40 patients and evaluated vaccine immunogenicity in 35 of them. Seroconversion (> 0.8 U/mL) was achieved in all patients, and the median antibody titer was 598 U/mL (interquartile range, 89-1380 U/mL). Patients using mycophenolate mofetil (MMF) showed lower antibody titers than those who were not (median: 272 U/mL vs. 2660 U/mL, p = 0.0002), and serum immunoglobulin G (IgG) levels showed a weak linear relationship with antibody titers (R² = 0.16). No breakthrough infections were noted. Three patients (7.5%) suffered from a relapse of nephrotic syndrome (2 and 3 days, respectively, after the first dose and 8 days after the second dose), two of whom had a history of relapse within 6 months before the vaccination.

CONCLUSIONS

The SARS-CoV-2 mRNA vaccine was immunogenic in patients with nephrotic syndrome using immunosuppressive agents, although the use of MMF and low levels of serum IgG were associated with lower antibody titers after vaccination. Patients with high disease activity may experience a relapse of nephrotic syndrome after vaccination. A higher resolution version of the Graphical abstract is available as Supplementary information.

Immunogenicity of SARS-CoV-2 mRNA intramuscular vaccination in patients with muscular disorders

Backgrounds

Little clinical data is available on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with muscular disorders (MDs). The immunogenicity of SARS-CoV-2 vaccines against MDs, in particular, remains unknown. Thus, this study aimed to confirm the immunogenicity and safety of the SARS-CoV-2 vaccine against MDs.

Methods

All participants were vaccinated with two doses of mRNA vaccines (BNT162b2, Pfizer-BioNTech). The serum samples were collected from each patient on the day of second dose of vaccination, and then, consecutively, after one month, three months, and six months. Anti-SARS-CoV-2 IgG levels were determined using the Abbott SARS-CoV-2 IgG II Quant assay.

Results

We evaluated 75 individuals, including 42 patients with MDs and 33 patients with non-muscular disorders (non-MDs). Non-MD patients primarily include those with severe motor and intellectual disabilities. The median age of the patients was 32 years (range 12-64 years). After one and three months following the second immunization, patients with MDs had lower antibody responses. Furthermore, three months following the second immunization, the proportion of high responders among patients with MDs decreased significantly compared to that among patients without MDs (p-value of less than 0.01). No serious adverse events were observed in patients with or without MDs.

Conclusion

Intensity and latency of antibody response were suppressed in patients with MDs. Although MDs may be a key contributor in predicting the antibody response to SARS-CoV-2 vaccination, SARS-CoV-2 immunization in MDs needs extensive research.

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.

Torquetenovirus viral load is associated with anti-spike antibody response in SARS-CoV-2 mRNA BNT162b2 vaccinated kidney transplant patients

INTRODUCTION

Kidney transplant patients (KT) are at high risk for severe COVID-19 and presented attenuated antibody responses to vaccination when compared to immunocompetent individuals. Torquetenovirus (TTV) has recently gained attention as a potential surrogate marker of the net state of immunosuppression. We evaluated the association between pre-vaccination TTV viral load and anti-spike total antibody response to SARS-CoV-2 vaccination in KT.

MATERIAL AND METHODS

The 114 adult KT recipients enrolled in this prospective single-center cohort study received two doses of SARS-CoV-2 mRNA BNT162b2 vaccine. Serum samples were collected immediately before vaccination at the days when patients received both the first (T0) and the second dose (T1) and 16-45 days after the second dose (T2). Primary endpoint was the development of anti-spike total antibodies after vaccination. Demographic, clinical, and laboratorial parameters were compared between patients with and without detectable SARS-CoV-2 antibodies at T2.

RESULTS

Ninety-nine patients (86.8%) were naïve for SARS-CoV-2 before vaccination. Fifty-six (56.6%) patients developed anti-spike total antibodies at T2. The use of mTOR inhibitors was associated with a favorable response (p = .005); conversely, mycophenolic acid (MPA) was associated with a negative response (p = .006). In a multivariable model, the presence of TTV at T0 ≥ 3.36 log₁₀ cp/ml was associated with unfavorable vaccine response (OR: 5.40; 95% CI: 1.47-19.80; p = .011), after adjusting for age and eGFR at T0.

CONCLUSIONS

Higher TTV viral loads before vaccination are associated with reduced anti-spike total antibody response in SARS-CoV-2 mRNA BNT162b2 vaccinated KT patients. The association between TTV viral load and vaccine response may be an added-value in the optimization of vaccination regimens in KT.

Torque teno virus DNA load as a predictive marker of antibody response to a three-dose regimen of COVID-19 mRNA-based vaccine in lung transplant recipients

BACKGROUND

Previous studies have reported that lung transplant recipients (LTR) develop a poor response to two doses of COVID-19 vaccine, but data regarding the third dose are lacking. We investigated the antibody response after three doses of mRNA vaccine in LTR and its predictive factors.

METHODS

A total of 136 LTR, including 10 LTR previously infected and 126 COVID-19-naive LTR, were followed during and after three doses of mRNA vaccine. We retrospectively measured anti-receptor-binding domain (RBD) IgG response and neutralizing antibodies. In a posthoc analysis, we used a multivariate logistic regression model to assess the association between vaccine response and patient characteristics, including viral DNA load (VL) of the ubiquitous Torque teno virus (TTV) (optimal cut-off set by ROC curve analysis), which reflects the overall immunosuppression.

RESULTS

After 3 doses, 47/126 (37.3%) COVID-19-naive LTR had positive anti-RBD IgG (responders) and 14/126 (11.1%) had antibody titers above 264 Binding Antibody Units/mL. None neutralized the omicron variant versus 7 of the 10 previously infected LTR. Nonresponse was associated with TTV VL ≥6.2 log₁₀ copies/mL before vaccination (Odds Ratio (OR) = 17.87, 95% confidence interval (CI95) = 3.02-105.72), mycophenolate treatment (OR = 4.73, CI95 = 1.46-15.34) and BNT162b2 (n = 34; vs mRNA-1273, n = 101) vaccine (OR = 6.72, CI95 = 1.75-25.92). In second dose non-responders, TTV VL ≥6.2 or <3.2 log₁₀ copies/mL before the third dose was associated with low (0/19) and high (9/10) rates of seroconversion.

CONCLUSION

COVID-19-naive LTR respond poorly to three doses of mRNA vaccine, especially those with high TTV VL. Future studies could further evaluate this biomarker as a guide for vaccine strategies.

Humoral Immunogenicity to SARS-CoV-2 Vaccination in Liver Transplant Recipients: A Systematic Review and Meta-Analysis

Solid organ transplant recipients generally show reduced immunogenicity to various vaccines. We aimed to assess the immunogenicity of the immune response among orthotopic liver transplant (OLT) recipients after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. A systematic search was performed to evaluate immunogenicity or adverse events reported after SARS-CoV-2 vaccination. The pooled analysis of 20 studies showed a humoral immune response rate of 0.70 (95% confidence interval [CI], 0.63-0.77) after SARS-CoV-2 vaccination among OLT recipients. The immunogenicity among OLT recipients was significantly lower compared to the overall population and healthy controls, with odds ratios (ORs) of 0.80 and 0.69. However, it was significantly higher than that of patients receiving other organ transplants, especially kidneys, with an OR of 1.50. Male sex, old age, chronic kidney disease, obesity, and multiple or high immunosuppressant doses significantly increased the risk of unresponsiveness in patients with OLT. The overall incidence of any adverse event after vaccination was 0.68 (95% CI, 0.55-0.81), similar to that of control. OLT recipients had an overall humoral immune response rate of 70% after SARS-CoV-2 vaccination, which is lower than that of healthy controls but favourable compared to those of other solid organ transplant recipients.

Mycophenolate mofetil decreases humoral responses to three doses of SARS-CoV-2 vaccine in liver transplant recipients

BACKGROUND AND AIMS

After 2 doses, the efficacy of anti-SARS-CoV-2 vaccination seems to be lower in solid organ transplant recipients than in the immunocompetent population. The objective of this study was to determine the humoral response rate after vaccination, including with a booster dose, and to identify risk factors for non-responsiveness in liver transplant recipients.

METHODS

We included all patients seen in consultation in two French liver transplant centres between January 1, 2021, and March 15, 2021.

RESULTS

598 liver transplant recipients were enrolled and 327 were included for analysis. Sixteen patients received one dose, 63 patients two doses and 248 patients three doses. Anti-SARS-Cov-2 antibodies were detected in 242 out of 327 (74.0%) liver transplant patients after vaccination. Considering an optimal serologic response defined as an antibody titre >260 BAU/ml, 172 patients (52.6%) were responders. Mycophenolate mofetil (MMF) treatment was an independent risk factor for a failure to develop anti-SARS-CoV-2 antibodies after vaccination (OR 0.458; 95%CI 0.258-0.813; p = .008). Conversely, male gender (OR 2.247, 95%CI 1.194-4.227; p = .012) and receiving an mRNA vaccine (vs a non-mRNA vaccine) (OR 4.107, 95%CI 1.145-14.731; p = .030) were independent predictive factors for developing an optimal humoral response after vaccination. None of the patients who received the vaccine experienced any serious adverse events.

CONCLUSIONS

Even after a third booster dose, response rate to vaccination is decreased in liver transplant recipients. MMF appears to be a major determinant of seroconversion and optimal response to vaccination in these patients.

Outcomes of COVID-19 in a Large Cohort of Lung Transplant Recipients: A Retrospective Study

Background: Early reports of COVID-19 in lung transplant recipients (LTRs) showed high hospitalization and mortality rates. However, the outcomes of COVID-19 in LTRs since the advent of newer therapies and vaccines have been poorly defined. Methods: We evaluated the risks for SARS-CoV-2-related hospitalization and mortality in a cohort of LTRs at the Henry Ford Lung Transplant Program in Detroit, Michigan during the study period March 2020–March 2022. Univariate logistic regression, followed by multivariable modeling were performed to estimate the odds ratio (OR) with 95% confident intervals (CI). Results: Sixty-four laboratory-confirmed SARS-CoV-2 infections were identified in 59 patients. For the primary analysis of the hospitalization and mortality risks, we included these 59 patients with symptomatic COVID-19. SARS-CoV-2 infections were confirmed with real-time polymerase chain reaction (RT-PCR) from a nasopharynx swab. The mean age (±STD) was 61 (±12), 63% were males, 27% were African Americans, and the time from lung transplant to COVID-19 was 5.5 (±4.8) years. Thirty-four (57.6%) patients were hospitalized, and the inpatient mortality rate was 24% (8/34). A multivariable analysis showed that patients with a higher baseline forced expiratory volume (FEV1) were less likely to be hospitalized (OR = 0.91 and 95% CI 0.87–0.98, p = 0.02). Seventy-five percent (75%; 6/8) of patients on invasive mechanical ventilation died, compared with only 8% mortality rate in those without mechanical ventilation (OR = 36.0 and 95% CI 4.2–310.4, p < 0.01). Although a trend toward a higher risk of death was observed in those infected during the Alpha (p = 0.17) and Delta (p = 0.22) waves, no significant risk was detected after adjusting for other covariates. Five LTRs were diagnosed with COVID-19 twice. Thirty of the sixty-four COVID-19 cases (46.8%) occurred in LTRs that had received at least two doses of any of the available mRNA vaccines at a median of 123 days (IQR 98–164 days) after vaccination. Twelve of the thirty (40%) were hospitalized, and four patients (33%) died during their hospitalizations. Conclusions: In our LTR population, the hospitalization and mortality rates associated with COVID-19 were high despite the increased use of new therapies. Vaccine-breakthrough infections were common and were associated with poor outcomes. Studies are needed to determine optimal prevention and therapeutic strategies to improve COVID-19 outcomes in LTRs.

Humoral and Cellular Immune Responses of Solid Organ Transplant Patients on Belatacept to Three Doses of mRNA-Based Anti-SARS-CoV-2 Vaccine

Background: Two doses of anti-SARS-CoV-2 mRNA-based vaccines are poorly immunogenic in solid organ transplant recipients (SOT). Methods: In total, 68 belatacept-treated SOT recipients followed at the Toulouse University Hospital were investigated. They were given three injections of the BNT162b2 mRNA COVID-19 vaccine. Their humoral response was assessed by determining anti-spike antibodies and neutralizing antibodies. The T-cell responses were assessed using an enzyme-linked immunospot assay that measured the interferon-γ produced by specific SARS-CoV-2 T-cells in a subgroup of 17 patients. Results: Only 23.5% of these patients developed a detectable anti-spike response. Moreover, the cellular and the humoral responses were well correlated. Patients with no humoral response were also without a detectable cellular response. Those belatacept-treated patients who developed an Anti-SARS-CoV-2 humoral response were younger, had been transplanted for longer, and had a higher lymphocyte count and a better glomerular filtration rate than those with no response. Finally, patients on tacrolimus plus belatacept produced a lower immune response. Conclusions: Belatacept-treated SOT recipients have a reduced immune response to anti-SARS-CoV-2 mRNA vaccination. The vaccine should be given quite separately from the belatacept infusion to improve immunogenicity. Studies to assess whether switching to another immunosuppressive regimen can improve the post-vaccination immune response would be useful.