SARS-COV-2 vaccination with BNT162B2 in renal transplant patients: Risk factors for impaired response and immunological implications

Low Incidence of Rejection and De Novo Donor-Specific Antibody Formation Following COVID-19 Vaccination or Infection Among Pediatric Kidney Transplant Recipients

BACKGROUND

Studies in adults have demonstrated a risk for allograft rejection or development of donor-specific antibodies (DSA) following SARS-CoV-2 vaccination. We examined the incidence of acute rejection and de novo DSA following COVID-19 vaccination or infection among pediatric kidney transplant patients.

METHOD

Retrospective analysis of 23 pediatric kidney transplant recipients without prior history of rejection, DSA, or COVID-19 infection who received the SARS-CoV-2 mRNA vaccine. Risk for rejection was evaluated via monitoring of serum creatinine, DSA, and donor-derived cell-free DNA per center protocol. Results concerning for rejection prompted allograft biopsy, graded by the Banff classification system.

RESULTS

Eight of 23 (34.8%) received two doses of SARS-CoV-2 mRNA vaccine, 15 (65.3%) received three doses. Two (8.7%) had rejection; one with de novo DSA, another without. There was no difference in the number of doses of COVID-19 vaccine received in those with rejection vs. no rejection (p = 0.53). 13 (56.5%) developed SARS-CoV-2 infection, with no difference in the number of vaccines received between those infected with COVID-19 vs. those who were not (p = 0.69). No adjustments were made to the maintenance immunosuppression during SARS-CoV-2 infection, and there was no evidence of rejection or DSA formation after infection. Median follow-up time was 29.9 months (IQR 25.0-33.4 months) after the first vaccine dose.

CONCLUSION

In our small single-center cohort, SARS-CoV-2 vaccination or infection is unlikely to increase the risk for rejection or de novo DSA in pediatric kidney transplant recipients. Larger prospective studies with a control group are needed to further understand the immune effects of the COVID-19 vaccine and disease in this population.

Impact of COVID-19 on Renal Transplant Recipients in a National Transplant Center

BACKGROUND

Renal transplant recipients are at higher risk of COVID-19 infection due to chronic comorbidities and immunocompromised state. Limited information is available in Nepal regarding this infection among organ transplantation patients.

METHODS

A retrospective cross-sectional study was conducted on 601 patients to assess the impact of COVID-19 among patients who underwent renal transplant surgery at Shahid Dharmabhakta National Transplant Center (SDNTC), Bhaktapur. All the renal transplant patients who were COVID-19 confirmed through PCR tests were included. A self-developed, semi-structured telephone interview schedule was utilized for data collection.

RESULTS

Among the patients who responded to our telephone calls, more than a quarter (37.9%) were diagnosed as COVID-19 positive. The mortality rate was relatively low at 5.7% overall, but significantly higher at 14.9% among those with COVID-19 positive. Hypertension and diabetes mellitus were the top two comorbid conditions. The common reporting symptom was fever followed by cough. Interestingly, 23.7% of COVID-19-positive patients were hospitalized, and among them, 72.2% were admitted for more than 2 days. Notably, 65.8% of the COVID-19 patients were not vaccinated and among vaccinated ones, only 17.1% of patients were fully vaccinated. The most common vaccine was Vero Cell. There was sixfold increased chance of COVID-19 infection among unvaccinated patients than vaccinated ones. However, there was no significant association between mortality and age, sex, occupation and vaccination status.

CONCLUSION

This study highlights the heightened vulnerability of renal transplant recipients to COVID-19 as significant portion of the studied patients tested positive for COVID-19, with a notable mortality rate among these patients. The findings underscore the critical role of vaccination, as a considerable number of the COVID-19 positive patients were unvaccinated.

Vaccination for solid organ transplanted patients: Recommendations, efficacy, and safety

Solid organ transplant recipients face unique challenges in managing their immunosuppressed status, making vaccination a critical consideration. This review aimed to comprehensively analyze current recommendations, evaluate the efficacy of vaccinations in this population, and assess safety concerns. We explored the latest evidence on vaccine types, timing, and potential benefits for transplant patients, highlighting the importance of individualized approaches for routinely used vaccines as well as coronavirus disease 2019 vaccines. By synthesizing available data, this review underscored the pressing need to optimize vaccination strategies, ensuring that transplant recipients can obtain the full protection against many pathogens while minimizing risks associated with their post-transplant immunosuppression.

Delayed peak antibody titers after the second dose of SARS-CoV-2 vaccine in solid organ transplant recipients: Prospective cohort study

Poor post-vaccination production of antibody against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a concern among solid organ transplant (SOT) recipients. Furthermore, the timing and kinetics of antibody titers after the second vaccine dose are unknown. We conducted a multicenter prospective observational study that included 614 SOT recipients: 460 kidney, 53 heart, 50 liver, 20 lung, and 31 simultaneous pancreas-kidney (SPK). The participants received two doses of the mRNA vaccine (Pfizer BNT162b2 or Moderna mRNA-1273), as indicated. Serum samples were collected before the first and second vaccinations and at 1, 3, and 6 months after the second vaccine dose, which were then assessed for SARS-CoV-2 antibodies. The overall seropositivity rate was 43% at 1 month after administration of the second vaccine dose; it gradually increased to 68% at 3 months after second dose administration and to 70% at 6 months. In addition, recipient of kidney, lung or SPK transplants had lower antibody titers at the 3- and 6-month time points than did the other recipients. SOT recipients acquired SARS-CoV-2 S-IgG antibodies slowly, and the peak titer differed significantly from that of the general population.

Development of donor specific antibodies after SARS-CoV-2 vaccination: What do we know so far?

Vaccination against Coronavirus disease-19 (COVID-19) was pivotal to limit spread, morbidity and mortality. Our aim is to find out whether vaccines against COVID-19 lead to an immunological response stimulating the production of de novo donor specific antibodies (DSAs) or increase in mean fluorescence intensity (MFI) of pre-existing DSAs in kidney transplant recipients (KTRs). This study involved a detailed literature search through December 2^nd, 2023 using PubMed as the primary database. The search strategy incorporated a combination of relevant Medical Subject Headings terms and keywords: "COVID-19", "SARS-CoV-2 Vaccination", "Kidney, Renal Transplant", and "Donor specific antibodies". The results from related studies were collated and analyzed. A total of 6 studies were identified, encompassing 460 KTRs vaccinated against COVID-19. Immunological responses were detected in 8 KTRs of which 5 had increased MFIs, 1 had de novo DSA, and 2 were categorized as either having de novo DSA or increased MFI. There were 48 KTRs with pre-existing DSAs prior to vaccination, but one study (Massa et al) did not report whether pre-existing DSAs were associated with post vaccination outcomes. Of the remaining 5 studies, 35 KTRs with pre-existing DSAs were identified of which 7 KTRs (20%) developed de novo DSAs or increased MFIs. Overall, no immunological response was detected in 452 (98.3%) KTRs. Our study affirms prior reports that COVID-19 vaccination is safe for KTRs, especially if there are no pre-existing DSAs. However, if KTRs have pre-existing DSAs, then an increased immunological risk may be present. These findings need to be taken cautiously as they are based on a limited number of patients so further studies are still needed for confirmation.

Safety and infectious outcomes in pediatric kidney transplant recipients after COVID-19 vaccination: A pediatric nephrology research consortium study

BACKGROUND

Adult kidney transplant recipients (KTRs) fully vaccinated against COVID-19 have substantial morbidity and mortality related to SARS-CoV-2 infection compared with the general population. However, little is known regarding the safety and efficacy of the COVID-19 vaccination series in pediatric KTRs.

METHODS

A multicenter, retrospective observational study was performed across nine pediatric transplantation centers. Eligible KTRs fully vaccinated against COVID-19 were enrolled and data were collected pertaining to SARS-CoV-2 infection incidence and severity, graft outcomes and post-vaccination safety profile, as well as overall patient survival.

RESULTS

A total of 247 patients were included in this investigation with a median age at transplantation of 11 years (IQR 5-15). SARS-CoV-2 infection was observed in 30/110 (27.27%) of fully vaccinated patients, tested post-transplant, within the defined follow-up period. Of these patients, 6/30 (18.18%) required hospitalization and 3/30 (12.12%) required reduction in immunosuppression, with no reported deaths. De novo donor-specific antibodies (DSAs) were found in 8/86 (9.30%) of DSA-tested patients with two experiencing rejection and subsequent graft loss. The overall incidence of rejection and graft loss among the total cohort was 11/247 (4.45%) and 6/247 (3.64%), respectively. A 100% patient survival was observed.

CONCLUSIONS

Observationally, infectious outcomes of SARS-CoV-2 in fully vaccinated pediatric KTRs are excellent, with a low incidence of infection requiring hospitalization and no associated deaths. Though de novo DSAs were observed, there was minimal graft rejection and graft loss reported in the total cohort.

Prevalence of SARS-CoV-2 antibodies and associated factors in the adult population of Belgium: a general population cohort study between March 2021 and April 2022

BACKGROUND

This study assessed seroprevalence trends of SARS-CoV-2 antibodies in the Belgian adult population between March 2021 and April 2022, and explored factors associated with seropositivity and seroreversion among the vaccinated and unvaccinated population.

METHODS

A prospective longitudinal surveillance study was conducted within a random sample of the general population (18 + years) in Belgium, selected from the national register through a multistage sampling design. Participants provided a saliva sample and completed a survey questionnaire on three occasions: at baseline and in two follow-up waves. Outcome variables included (1) seropositivity, defined as the presence of SARS-CoV-2 antibodies, assessed with a semi-quantitative measure of anti-RBD (Receptor Binding Domain) IgG ELISA and (2) seroreversion, defined as passing from a positive to a negative antibody test between two measurements. Trends in SARS-CoV-2 antibody prevalence were assessed using binary logistic regression with contrasts applying post-stratification. Potential determinants of seropositivity were assessed through multilevel logistic regressions.

RESULTS

In total 6,178 valid observations were obtained from 2,768 individuals. SARS-CoV-2 antibody prevalence increased from 25.1% in the beginning of the study period to 92.3% at the end. Among the vaccinated population, factors significantly associated with higher seropositivity rates were being younger, having a bachelor diploma, living with others, having had a vaccine in the last 3 months and having received a nucleic-acid vaccine or a combination. Lower seropositivity rates were observed among vaccinated people with a neurological disease and transplant patients. Factors significantly associated with higher seropositivity rates among the unvaccinated population were having non-O blood type and being non-smoker. Among vaccinated people, the seroreversion rate was much lower (0.3%) in those who had received their latest vaccine in the last 3 months compared to those who had received their latest vaccine more than 3 months ago (2.7%) (OR 0.13; 95%CI 0.04-0.42).

CONCLUSIONS

The rapid increase in antibody seropositivity in the general adult population in Belgium during the study period was driven by the vaccination campaign which ran at full speed during this period. Among vaccinated people, seropositivity varied in function of the time since last vaccine, the type of vaccine, sociodemographic features and health status.

Characteristics of COVID-19 Disease in Renal Transplant Recipients

Background and Objectives: Kidney transplant recipients are at risk of developing more severe forms of COVID-19 infection. The aim of this study was to compare the clinical course of COVID-19 infection among kidney transplant patients and a control group. Materials and Methods: We examined 150 patients hospitalized with COVID-19 infection. Patients were divided into study (kidney transplant recipients, n = 53) and control (without a history of kidney transplantation, n = 97) groups. Demographics, clinical characteristics, treatment data, and clinical outcomes were assessed. Results: The median patient age was 56.0 (46.0-64.0) years, and seventy-seven patients (51.3%) were men. The median Charlson comorbidity index was higher in the study group (3.0 vs. 2.0, p < 0.001). There was a higher incidence of hypoxemia in the control group upon arrival (52.6% vs. 22.6%, p = 0.001) and a higher NEWS index median (2.0 vs. 1.0 points, p = 0.009) and incidence of pneumonia during hospitalization (88.7% vs. 73.6%, p = 0.023). In the study group, there were more cases of mild (26.4% vs. 11.3%, p = 0.023) and critically severe forms of COVID-19 infection (26.4% vs. 3.1%, p < 0.001), kidney failure was more prevalent (34.0% vs. 1.0%, p < 0.001), and a greater number of patients were transferred to the intensive care unit (22.6% vs. 3.1%, p < 0.001) and died (18.9% vs. 1.0%, p < 0.001). Multivariable analysis revealed that treatment in the intensive care unit correlated with a higher mortality rate than transplantation itself (HR = 20.71, 95% CI 2.01-213.33, p = 0.011). Conclusions: The course of the COVID-19 disease in kidney transplant recipients is heterogeneous and can be more severe than in the general population. Even though patients may be hospitalized with fewer symptoms, complications and death are more likely to occur.

Severity of COVID-19 Pneumonia in Kidney Transplant Recipients According to SARS-CoV-2 Vaccination

We reviewed 24 kidney transplantat recipients (KTRs) who had radiologically confirmed coronavirus disease 2019 (COVID-19) pneumonia. Enrolled KTRs were divided into a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-vaccination (+) group (n = 18) and a vaccination (-) group (n = 6). Clinical outcomes of the two groups including death, pulmonary outcome, and renal outcome were compared. COVID-19 pneumonia was worse in vaccination (-) KTRs. Two out of six vaccination (-) KTRs needed continuous renal replacement therapy (CRRT) and mechanical ventilator (MV) and expired. In contrast, only one KTR expired and required CRRT and MV out of 18 vaccination (+) KTRs. Our results suggest that SARS-CoV-2 vaccination attenuates severity of COVID-19 pneumonia in KTRs.

Safety and efficacy of one and two booster doses of SARS-CoV-2 mRNA vaccines in kidney transplant recipients: A randomized clinical trial

BACKGROUND

Kidney transplant recipients are at risk for a severe course of COVID-19 with a high mortality rate. A considerable number of patients remains without a satisfactory serological response after the baseline and adjuvant SARS-CoV-2 vaccination schedule.

METHODS

In this prospective, randomized study, we evaluated the efficacy and safety of one and two booster doses of mRNA vaccines (either mRNA-1273 or BNT162b2) in 125 COVID-19 naive, adult kidney transplant recipients who showed an insufficient humoral response (SARS-CoV-2 IgG <10 AU/ml) to the previous 2-dose vaccination schedule. The primary outcome was the difference in the rate of a positive antibody response (SARS-CoV-2 IgG ≥10 AU/ml) between one and two booster doses at 1 month after the final booster dose.

RESULTS

A positive humoral response was observed in 36 (62%) patients receiving two booster doses and in 28 (44%) patients receiving one booster dose (odds ratio [OR], 2.10, 95% confidence interval [CI], 1.02-4.34, p = .043). Moreover, median SARS-CoV-2 IgG levels were higher with two booster doses (p = .009). The number of patients with positive virus neutralizing antibody (VNA) levels was numerically higher with two booster doses compared to one booster dose, but without statistical significance (66% vs. 50%, p = .084). There was no significant difference in positive seroconversions rate and antibody levels between mRNA-1273 and BNT162b2.

CONCLUSION

A higher number of kidney transplant recipients achieved a positive antibody response after two booster doses compared to one booster dose.

Update of the recommendations on the management of the SARS-CoV-2 coronavirus pandemic (COVID-19) in kidney transplant patients

SARS-CoV-2 infection (COVID-19) has had a significant impact on transplant activity in our country. Mortality and the risk of complications associated with COVID-19 in kidney transplant recipients (KT) were expected to be higher due to their immunosuppressed condition and the frequent associated comorbidities. Since the beginning of the pandemic in March 2020 we have rapidly improved our knowledge about the epidemiology, clinical features and management of COVID-19 post-transplant, resulting in a better prognosis for our patients. KT units have been able to adapt their programs to this new reality, normalizing both donation and transplantation activity in our country. This manuscript presents a proposal to update the general recommendations for the prevention and treatment of infection in this highly vulnerable population such as KT.

Humoral and Cellular Immunity following Five Doses of COVID-19 Vaccines in Solid Organ Transplant Recipients: A Systematic Review and Meta-Analysis

Solid organ transplant (SOT) recipients are at increased risk of COVID-19 infection because of their suppressed immunity. The available data show that COVID-19 vaccines are less effective in SOT recipients. We aimed to assess the cellular and humoral immunogenicity with an increasing the number of doses of COVID-19 vaccines in SOT recipients and to identify factors affecting vaccine response in this population. A systematic review and meta-analysis were conducted to identify ongoing and completed studies of humoral and cellular immunity following COVID-19 vaccines in SOT recipients. The search retrieved 278 results with 45 duplicates, and 43 records did not match the inclusion criteria. After title and abstract screening, we retained 189 records, and 135 records were excluded. The reasons for exclusion involved studies with immunocompromised patients (non-transplant recipients), dialysis patients, and individuals who had already recovered from SARS-CoV-2 infection. After full-text reading, 55 observational studies and randomized clinical trials (RCTs) were included. The proportion of responders appeared higher after the third, fourth, and fifth doses. The risk factors for non-response included older age and the use of mycophenolate mofetil, corticosteroids, and other immunosuppressants. This systematic review and meta-analysis demonstrates the immunogenicity following different doses of COVID-19 vaccines among SOT patients. Due to the low immunogenicity of vaccines, additional strategies to improve vaccine response may be necessary.

Analysis of Acquisition of COVID-2019 Neutralizing Antibodies in Organ Transplant Recipients

BACKGROUND

This study confirmed the kinetics of antibodies acquired by SARS-CoV-2 vaccination in solid-organ transplant recipients and examined their association with the development of COVID-19 and immunosuppressive status in organ transplant recipients.

METHODS

We measured COVID-19 neutralizing antibody titer in 21 organ transplant recipients vaccinated with the COVID-19 vaccine and 14 nontransplant recipients (control group) 3 times before and at 1 and 6 months after the third dose of vaccine. By confirming the kinetics of the acquired antibodies, we examined the relevance of the background characteristics of organ transplant recipients, such as the development of infectious diseases and immunosuppressive status.

RESULTS

The proportion of patients with neutralizing antibodies was significantly higher in the nontransplant group than in the transplant group. Neutralizing antibody titers were significantly lower in transplant recipients when they were compared before the third dose and 1 month later. In the transplant recipient group, 11 patients were positive, and 10 were negative for neutralizing antibodies. When the causal relationship between the neutralizing antibody titer and background was examined, a positive correlation was found between the antibody titer and the number of years since transplantation, and a negative correlation was found between the tacrolimus trough values, amount of mycophenolate mofetil or steroids taken internally, and antibody titer.

CONCLUSION

This study suggests that the effectiveness of vaccination in transplant recipients is associated with the post-transplant period before vaccination and the dose of immunosuppressive agents.

Immunologic response to SARS-CoV-2 mRNA vaccination in pediatric kidney transplant recipients

BACKGROUND

COVID-19 disease in kidney transplant (KT) recipients is associated with increased morbidity, mortality, and hospitalization rates. Unfortunately, KT recipients also have a reduced response to SARS-CoV-2 immunization. The primary aim of this study was to assess immunologic response to SARS-CoV-2 mRNA vaccines in pediatric kidney transplant recipients 12-18 years of age. Secondary aims were to assess response rates following a third immunization and determine factors that influence immunization response.

METHODS

Pediatric KT recipients in a single tertiary center received SARS-CoV-2 mRNA vaccination as per local protocol. SARS-CoV-2 immunoglobulin (IgG) was measured following second and/or third vaccination. Demographics including patient factors (age, gender, and underlying disease), transplant factors (time and type of transplant), and immunosuppression (induction, maintenance, and immunomodulatory therapies such as IVIG) were collected from the medical records.

RESULTS

Of 20 participants, 10 (50%) responded following a two-dose vaccine schedule, which increased to 15 (75%) after three doses. Maintenance immunosuppression affected immunologic response, with azathioprine demonstrating a higher rate of response to vaccine compared to mycophenolate (100% vs. 38%, p = 0.04). Increasing prednisolone dose had a negative impact on immunologic response (0.01 mg/kg/day increase: OR 1.60 95% CI 1.01 to 2.57). Tacrolimus dose and trough levels, age, time post-transplant, underlying disease, and other immunosuppression did not impact immunologic response.

CONCLUSIONS

Pediatric KT recipients had similar response rates following SARS-CoV-2 immunization as adult KT recipients. Immunologic response improved following a third immunization. Choice of antimetabolite and prednisolone dosing influenced the rate of response. A higher resolution version of the Graphical abstract is available as Supplementary Information.

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.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

INTERPRETATION

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

A systematic review assessing the effectiveness of COVID-19 mRNA vaccines in chronic kidney disease (CKD) individuals

Background: SARS-CoV-2 is a coronavirus that has rapidly spread across the world with a detrimental effect on the global population. Several reports have highlighted an increased mortality rate and a higher severity of COVID-19 infection in chronic kidney disease (CKD) individuals. Upon the development of various SARS-CoV-2 vaccines, mRNA vaccines including BNT162b2 and mRNA-1273 were deemed safe, with a high efficacy in preventing COVID-19 in the general population. This review investigates whether  SARS-CoV-2 mRNA vaccines are as effective in triggering an immune response in Dialysis Patients (DPs) and Kidney Transplant Recipients (KTRs) and if a third dose is required in this  population. Methods: A systematic search employing the PRISMA criteria was conducted in several major databases, with the data being extracted from publications for the period January 2021 to May 2022 (PROSPERO: CRD42022338514, June 15, 2022). Results: 80 studies were included in this analysis with a total cohort number of 15,059 participants. Overall, 85.29% (OR = 17.08, 95% CI = 15.84-18.42, I ² = 98%) and 41.06% (OR = 0.52, 95% CI = 0.48-0.5, I ² = 95%) of DPs and KTRs included in this review showed positive seroconversion after two doses of either mRNA vaccine, respectively. A total 76% (OR = 6.53, 95% CI = 5.63-7.5, I ² = 96%) of the cohort given a third dose of an mRNA vaccine demonstrated positive seroconversion, with 61.86% (OR = 2.31, 95% CI = 1.95-2.75 I ² = 95%) of the cohort that was assessed for a cellular response displaying a positive response. Conclusions: This data emphasises a reduced incidence of a positive immune response in DPs and KTRs compared to healthy controls, albeit a better response in DPs than when compared to KTRs alone was observed. A third dose  appears to increase the occurrence of an immune response in the overall DP/KTR cohort.

[Update of the recommendations on the management of the SARS-CoV-2 coronavirus pandemic (COVID-19) in kidney transplant patients.]

SARS-CoV-2 infection (COVID-19) has had a significant impact on transplant activity in our country. Mortality and the risk of complications associated with COVID-19 in kidney transplant recipients (KT) were expected to be higher due to their immunosuppressed condition and the frequent associated comorbidities. Since the beginning of the pandemic in March 2020 we have rapidly improved our knowledge about the epidemiology, clinical features and management of COVID-19 post-transplant, resulting in a better prognosis for our patients. KT units have been able to adapt their programs to this new reality, normalizing both donation and transplantation activity in our country.This manuscript presents a proposal to update the general recommendations for the prevention and treatment of infection in this highly vulnerable population such as KT.

COVID-19 Vaccination in Kidney Transplant Candidates and Recipients

Kidney transplant candidates and kidney transplant recipients (KTRs) are at particular risk of severe complications of COVID-19 disease. In Western countries, mortality in affected hospitalized KTRs ranges between 19% and 50%. COVID-19 vaccination remains the most important measure to prevent the severity of infection in candidates and recipients of kidney transplant. However, the uraemic condition may affect the vaccine-induced immunity in patients with advanced chronic kidney disease (CKD) and in KTRs. Retention of uraemic toxins, dysbiosis, dysmetabolism, and dialysis can diminish the normal response to vaccination, leading to dysfunction of inflammatory and immune cells. In KTRs the efficacy of vaccines may be reduced by the immunosuppressive medications, and more than half of kidney transplant recipients are unable to build an immune response even after four administrations of anti-COVID-19 vaccines. The lack of antibody response leaves these patients at high risk for SARS-CoV-2 infection and severe COVID-19 disease. The aim of the present review is to focus on the main reasons for the impaired immunological response among candidates and kidney transplant recipients and to highlight some of the present options available to solve the problem.

SARS-CoV-2 anti-spike antibodies after a fourth dose of COVID-19 vaccine in adult solid-organ transplant recipients

BACKGROUND

A fourth dose of SARS-CoV-2 vaccine is recommended in solid-organ transplant (SOT) recipients, but the immunogenicity is poorly known.

METHODS

We conducted a retrospective, observational, monocentric study between the 1st January 2021 and 31st March 2022 of the anti-Spike antibody titers after one to four doses of vaccine in SOT.

RESULTS

825 SOT were included. Median age at first vaccine injection was 61.2 (IQR 50.9-69.3) years; 66.7 % were male; 63.4 % had received four vaccine doses. The proportion of participants with a strong humoral response (>260 BAU/mL) increased with the number of vaccine doses: 10.6 % after the 1st dose (D1), 35.1 % after the 2nd (D2), 48.5 % after the 3rd (D3), and 65.1 % after the 4th (D4) (p < 0.001). Among the tested patients, the proportion with a detectable humoral response was significantly higher after D4 than after D3 (47 % vs 22 %, p = 0.01). Liver transplant recipients had more frequently a strong humoral response after D2, D3 and D4 (OR = 5.3, 3.7 and 6.6 respectively when compared with other organ transplant recipients, p < 0.001). In kidney transplant recipients, belatacept-containing regimen was associated with a lower rate of detectable humoral (9 % vs 40 %, p = 0.025) after D3, but there was no statistical difference after D4.

CONCLUSION

A fourth dose should be proposed to SOT recipients who did not developed an immune response after 3 doses. Kidney transplant recipients receiving belatacept have a poorer, although frequently detectable response.

Analysis of Cross-sectional and Longitudinal HLA and Anti-viral Responses After COVID Infection in Renal Allograft Recipients: Differences and Correlates

BACKGROUND

Characterization of anti-HLA versus anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) immune globulin isotypes in organ transplant recipients after coronavirus disease 2019 (COVID-19) infection has not been reported. We aimed to determine changes in anti-HLA antibodies in renal transplant patients with COVID-19 and compare the immunoglobulin and epitope-binding pattern versus anti-SARS-CoV-2 antibodies.

METHODS

This is a cross-sectional study of 46 kidney transplant recipients including 21 with longitudinal sampling. Using a semi-quantitative multiplex assay, we determined immunoglobulin (Ig) M, IgA, IgG, and IgG1-2-3-4 antibodies against Class I and Class II HLA, and 5 SARS-CoV-2 epitopes including the nucleocapsid protein and multiple regions of the spike protein.

RESULTS

Fourteen of 46 (30%) patients had donor-specific anti-HLA antibodies (donor-specific antibody [DSA]), 12 (26%) had non-DSA anti-HLA antibodies and 45 (98%) had anti-SARS-CoV-2 antibodies. Most DSAs targeted HLA-DQ (71%), with a dominant IgG isotype and IgG1 subtype prevalence (93%), and/or IgG3 (64%), followed by IgG2 (36%). Comparatively, there was a higher prevalence of IgA (85% versus 14%, P = 0.0001) and IgM (87%, versus 36%, P = 0.001) in the anti-SARS-CoV-2 antibody profile, when compared to DSAs, respectively. Anti-SARS-CoV-2 antibody profile was characterized by increased prevalence of IgM and IgA, when compared to DSAs. The median calculated panel reactive antibody before COVID-19 diagnosis (24%) tended to decrease after COVID-19 diagnosis (10%) but it was not statistically significant ( P = 0.1).

CONCLUSIONS

Anti-HLA antibody strength and calculated panel reactive antibody in kidney transplant recipients after COVID-19 do not significantly increase after infection. Although the IgG isotype was the dominant form in both HLA and SARS-CoV-2 antigens, the alloimmune response had a low IgA pattern, whereas anti-SARS-CoV-2 antibodies were high IgA/IgM.

Heterologous vector versus homologous mRNA COVID-19 booster vaccination in non-seroconverted immunosuppressed patients: a randomized controlled trial

Impaired response to COVID-19 vaccination is of particular concern in immunosuppressed patients. To determine the best vaccination strategy for this vulnerable group we performed a single center, 1:1 randomized blinded clinical trial. Patients who failed to seroconvert upon two mRNA vaccinations (BNT162b2 or mRNA-1273) are randomized to receive either a third dose of the same mRNA or the vector vaccine ChAdOx1 nCoV-19. Primary endpoint is the difference in SARS-CoV-2 spike antibody seroconversion rate between vector and mRNA vaccinated patients four weeks after the third dose. Secondary outcomes include cellular immune responses. Seroconversion rates at week four are significantly higher in the mRNA (homologous vaccination, 15/24, 63%) as compared to the vector vaccine group (heterologous vaccination, 4/22, 18%). SARS-CoV-2-specific T-cell responses are reduced but could be increased after a third dose of either vector or mRNA vaccine. In a multivariable logistic regression analysis, patient age and vaccine type are associated with seroconversion. No serious adverse event is attributed to COVID-19 booster vaccination. Efficacy and safety data underline the importance of a booster vaccination and support the use of a homologous mRNA booster vaccination in immunosuppressed patients.Trial registration: EudraCT No.: 2021-002693-10.

Predictors of seroconversion after coronavirus disease 2019 vaccination

BACKGROUND

Vaccine nonresponse during the coronavirus disease 2019 (COVID-19) pandemic has considerable individual and societal risks.

OBJECTIVE

To investigate the clinical characteristics of patients with lack of seroconversion after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

Demographic and clinical data were collected from 805 patients who had validated antibody assays against the SARS-CoV-2 spike protein at least 14 days after completion of their COVID-19 vaccination. Clinical characteristics from patients with a negative (< 0.4 U/mL) antibody response were assessed and summarized.

RESULTS

A total of 622 (77.3%) patients attained seroconversion as defined by a titer of greater than or equal to 0.4 U/mL, whereas 183 out of 805 (22.7%) patients exhibited no seroconversion after vaccination against SARS-CoV-2. Univariately, older age (P = .02) and male sex were associated with a lower likelihood of seroconversion (P = .003). Therapy with immunosuppressive drugs was noted in 93 (50.8%) of seronegative patients with most (n = 83/93, 89.2%) receiving ongoing immunosuppressive therapy at the time of vaccination. Among the 134 (73.2%) seronegative patients with immunodeficiency, 110 (82.1%) had primary immunodeficiency. Cancer (n = 128, 69.9%), B cell depletion therapy (n = 90/115, 78.3%), and immunosuppressant steroid use (n = 71/93 on immunosuppressants, 76.3%) were the other common characteristics among the vaccine nonresponders. More importantly, our study did not evaluate the actual efficacy of COVID-19 vaccination.

CONCLUSION

Vaccine responses vary by age and sex, with men showing lower rates of seroconversion as compared with women. Primary immunodeficiency along with active malignancy and ongoing immunosuppression with steroids or B cell depletion therapy appeared to be the most common characteristics for those with a lack of vaccine seroconversion after COVID-19 vaccination.

Immunogenicity and safety of two doses of SARS-CoV-2 mRNA vaccine in kidney transplant recipients with low-dose rituximab

OBJECTIVES

We evaluated whether the treatment history of low-dose rituximab affected safety profiles, and humoral and cellular responses induced by severe acute respiratory syndrome coronavirus 2 messenger ribonucleic acid vaccine in healthy controls and kidney transplant recipients.

METHODS

We enrolled 10 healthcare workers as controls, 22 kidney transplant recipients with rituximab, and 36 kidney transplant recipients without rituximab without history of coronavirus disease 2019 who received two doses of vaccine. We assessed anti-severe acute respiratory syndrome coronavirus 2 spike antibody and the antigen-specific T cells using enzyme-linked immunospot against spike protein at baseline and after two doses of vaccine.

RESULTS

All controls showed anti-severe acute respiratory syndrome coronavirus 2 antibody seroconversion and enzyme-linked immunospot positivity. Only 19/58 (33%) kidney transplant recipients experienced anti-severe acute respiratory syndrome coronavirus 2 antibody seroconversion and 31/58 (53%) kidney transplant recipients developed enzyme-linked immunospot assay positivity after vaccination. The anti-severe acute respiratory syndrome coronavirus 2 antibody seroconversion rate and enzyme-linked immunospot assay positivity rate after vaccination were not significantly different between kidney transplant recipients with or without rituximab. Multivariate regression analysis demonstrated rituximab was not associated with a lack of humoral and cellular responses to the vaccine.

CONCLUSIONS

Low-dose rituximab in kidney transplant recipients did not affect humoral or cellular responses to the severe acute respiratory syndrome coronavirus 2 messenger ribonucleic acid vaccine without severe systemic adverse events including the deterioration of kidney function.

Long-Term Humoral Response After a Second Dose of SARS-CoV-2 mRNA Vaccine in Japanese Kidney Transplant Recipients

Background

The mortality rate due to COVID-19 in kidney transplant recipients (KTRs) is 16.8 to 32%. Vaccination against COVID-19 is expected to contribute to the prevention of infection, severe disease, and mortality; however, it has been reported that the humoral response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine in KTRs is poor. Vaccination strategies against COVID-19 vary from country to country, and in Japan, the third dose is given 6 months after the second dose. Few studies have evaluated long-term humoral responses after the second dose of SARS-CoV-2 mRNA vaccine. In addition, the superiority of BNT162b2 vaccine and mRNA-1,273 vaccine in KTRs regarding humoral response is controversial.

Methods

Ninety-four KTRs were administered a second dose of the BNT162b2 or mRNA-1,273 vaccines, and anti-spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 antibody levels were measured 5 months (149.2 ± 45.5 days) later. The cutoff value of anti-S antibodies was defined ≥50 AU/ml and 1.4 Index for anti-N antibodies. The primary outcome was the rate of seropositivity, and factors associated with an appropriate humoral response were assessed by univariate and multivariate analysis.

Results

Of 94 KTRs, only 45 (47.9%) patients were positive for anti-S antibodies. The median anti-S SARS-CoV-2 IgG antibody titers was 35.3 (Interquartile range 3.8 to 159.7). Anti-N SARS-CoV-2 IgG antibodies in all patients were < 1.4 Index. Response to SARS-CoV-2 mRNA vaccines were 43.2 and 65% for BNT162b2 and mRNA-1,273, respectively (p = 0.152). In comparison with high-dose, low-dose of mycophenolic acid was a robust factor associated with an adequate humoral response.

Conclusion

The long-term humoral response after a second dose of SARS-CoV-2 mRNA vaccine in Japanese KTRs was poor. In comparison with high-dose, low-dose mycophenolic acid was related to an appropriate humoral response. Five months is too long to wait for a 3rd dose after 2nd dose of SARS-CoV-2 vaccine in KTRs. In this cohort, there was no statistical difference in humoral response to the BNT162b2 and mRNA-1,273 vaccines. Additional large observational studies and meta-analyses are needed to clarify the factors related to an appropriate humoral immune response to COVID-19 vaccination.

Risk Factors for Weak Antibody Response of SARS-CoV-2 Vaccine in Adult Solid Organ Transplant Recipients: A Systemic Review and Meta-Analysis

Objective

This is the first systematic review and meta-analysis to determine the factors that contribute to poor antibody response in organ transplant recipients after receiving the 2-dose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine.

Method

Data was obtained from Embase, PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Chinese Biomedical Literature Database (CBM). Studies reporting factors associated with antibody responses to the 2-dose SARS-CoV-2 vaccine in solid organ transplant recipients were included in our study based on the inclusion and exclusion criteria. Two researchers completed the literature search, screening, and data extraction. Randomized models were used to obtain results. Egger’s test was performed to determine publication bias. Sensitivity analysis was performed to determine the stability of the result. The heterogeneity was determined using the Galbraith plot and subgroup analysis.

Results

A total of 29 studies were included in the present study. The factors included living donor, BNT162b2, tacrolimus, cyclosporine, antimetabolite, mycophenolic acid (MPA) or mycophenolate mofetil (MMF), azathioprine, corticosteroids, high-dose corticosteroids, belatacept, mammalian target of rapamycin (mTOR) inhibitor, tritherapy, age, estimated glomerular filtration rate (eGFR), hemoglobin, and tacrolimus level were significantly different. Multivariate analysis showed significant differences in age, diabetes mellitus, MPA or MMF, high-dose corticosteroids, tritherapy, and eGFR.

Conclusion

The possible independent risk factors for negative antibody response in patients with organ transplants who received the 2-dose SARS-CoV-2 vaccine include age, diabetes mellitus, low eGFR, MPA or MMF, high-dose corticosteroids, and triple immunosuppression therapy. mTOR inhibitor can be a protective factor against weak antibody response.

Systematic Review Registration

PROSPERO, identifier CRD42021257965.

Effect of a Third Dose of SARS-CoV-2 mRNA BNT162b2 Vaccine on Humoral and Cellular Responses and Serum Anti-HLA Antibodies in Kidney Transplant Recipients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has severely impacted on public health, mainly on immunosuppressed patients, including solid organ transplant recipients. Vaccination represents a valuable tool for the prevention of severe SARS-CoV-2 infection, and the immunogenicity of mRNA vaccines has been evaluated in transplanted patients. In this study, we investigated the role of a third dose of the BNT162b2 vaccine in a cohort of kidney transplant recipients, analyzing both humoral and cell-mediated responses. We observed an increased immune response after the third dose of the vaccine, especially in terms of Spike-specific T cell response. The level of seroconversion remained lower than 50% even after the administration of the third dose. Mycophenolate treatment, steroid administration and age seemed to be associated with a poor immune response. In our cohort, 11/45 patients experienced a SARS-CoV-2 infection after the third vaccine dose. HLA antibodies appearance was recorded in 7 out 45 (15.5%) patients, but none of the patients developed acute renal rejection. Further studies for the evaluation of long-term immune responses are still ongoing, and the impact of a fourth dose of the vaccine will be evaluated.

Humoral immunity against SARS-CoV-2 variants including omicron in solid organ transplant recipients after three doses of a COVID-19 mRNA vaccine

Objectives

Solid organ transplant recipients (SOTR) receiving post‐transplant immunosuppression show increased COVID‐19‐related mortality. It is unclear whether an additional dose of COVID‐19 vaccines can overcome the reduced immune responsiveness against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) variants.

Methods

We analysed humoral immune responses against SARS‐CoV‐2 and its variants in 53 SOTR receiving SARS‐CoV‐2 vaccination.

Results

Following the initial vaccination series, 60.3% of SOTR showed no measurable neutralisation and only 18.9% demonstrated neutralising activity of > 90%. More intensive immunosuppression, antimetabolites in particular, negatively impacted antiviral immunity. While absolute IgG levels were lower in SOTR than controls, antibody titres against microbial recall antigens were higher. By contrast, SOTR showed reduced vaccine‐induced IgG/IgA antibody titres against SARS‐CoV‐2 and its delta variants and fewer linear B‐cell epitopes, indicating reduced B‐cell diversity. Importantly, a third vaccine dose led to an increase in anti‐SARS‐CoV‐2 antibody titres and neutralising activity across alpha, beta and delta variants and to the induction of anti‐SARS‐CoV‐2 CD4⁺ T cells in a subgroup of patients analysed. By contrast, we observed significantly lower antibody titres after the third dose with the omicron variant compared to the ancestral SARS‐CoV‐2 and the improvement in neutralising activity was much less pronounced than for all the other variants.

Conclusion

Only a small subgroup of solid organ transplant recipients is able to generate functional antibodies after an initial vaccine series; however, an additional vaccine dose resulted in dramatically improved antibody responses against all SARS‐CoV‐2 variants except omicron where antibody responses and neutralising activity remained suboptimal.

Case Report: Precision COVID-19 Immunization Strategy to Overcome Individual Fragility: A Case of Generalized Lipodystrophy Type 4

A 48-year-old patient affected with congenital generalized lipodystrophy type 4 failed to respond to two doses of the BNT162b2 vaccine, consisting of lipid nanoparticle encapsulated mRNA. As the disease is caused by biallelic variants of CAVIN1, a molecule indispensable for lipid endocytosis and regulation, we complemented the vaccination cycle with a single dose of the Ad26.COV2 vaccine. Adenovirus-based vaccine entry is mediated by the interaction with adenovirus receptors and transport occurs in clathrin-coated pits. Ten days after Ad26.COV2 administration, S- and RBD-specific antibodies and high-affinity memory B cells increased significantly to values close to those observed in Health Care Worker controls.

Immunogenicity and Risk Factors Associated With Poor Humoral Immune Response of SARS-CoV-2 Vaccines in Recipients of Solid Organ Transplant: A Systematic Review and Meta-Analysis

IMPORTANCE

Recipients of solid organ transplant (SOT) experience decreased immunogenicity after COVID-19 vaccination.

OBJECTIVE

To summarize current evidence on vaccine responses and identify risk factors for diminished humoral immune response in recipients of SOT.

DATA SOURCES

A literature search was conducted from existence of database through December 15, 2021, using MEDLINE, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov.

STUDY SELECTION

Studies reporting humoral immune response of the COVID-19 vaccines in recipients of SOT were reviewed.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data from each eligible study. Descriptive statistics and a random-effects model were used. This report was prepared following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Data were analyzed from December 2021 to February 2022.

MAIN OUTCOMES AND MEASURES

The total numbers of positive immune responses and percentage across each vaccine platform were recorded. Pooled odds ratios (pORs) with 95% CIs were used to calculate the pooled effect estimates of risk factors for poor antibody response.

RESULTS

A total of 83 studies were included for the systematic review, and 29 studies were included in the meta-analysis, representing 11 713 recipients of SOT. The weighted mean (range) of total positive humoral response for antispike antibodies after receipt of mRNA COVID-19 vaccine was 10.4% (0%-37.9%) for 1 dose, 44.9% (0%-79.1%) for 2 doses, and 63.1% (49.1%-69.1%) for 3 doses. In 2 studies, 50% of recipients of SOT with no or minimal antibody response after 3 doses of mRNA COVID-19 vaccine mounted an antibody response after a fourth dose. Among the factors associated with poor antibody response were older age (mean [SE] age difference between responders and nonresponders, 3.94 [1.1] years), deceased donor status (pOR, 0.66 [95% CI, 0.53-0.83]; I2 = 0%), antimetabolite use (pOR, 0.21 [95% CI, 0.14-0.29]; I2 = 70%), recent rituximab exposure (pOR, 0.21 [95% CI, 0.07-0.61]; I2 = 0%), and recent antithymocyte globulin exposure (pOR, 0.32 [95% CI, 0.15-0.71]; I2 = 0%).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, the rates of positive antibody response in solid organ transplant recipients remained low despite multiple doses of mRNA vaccines. These findings suggest that more efforts are needed to modulate the risk factors associated with reduced humoral responses and to study monoclonal antibody prophylaxis among recipients of SOT who are at high risk of diminished humoral response.

SARS-CoV-2 Vaccines: Safety and Immunogenicity in Solid Organ Transplant Recipients and Strategies for Improving Vaccine Responses

Purpose of Review

While solid organ transplant (SOT) recipients are at the highest risk for severe complications and increased mortality from COVID19 disease, their vaccination against SARS-CoV-2 remains challenging due to fear of immune-mediated adverse events and suboptimal immune response. Our current review is aimed to summarize current knowledge about the safety and efficacy of SARS-CoV-2 vaccines, describe factors that are correlated with immune response, and discuss strategies to improve vaccine immunogenicity in SOT recipients.

Recent Findings

SARS-CoV-2 vaccines are safe in SOT recipients and not related to rejection or other major adverse events. The immune response to two doses of vaccine is suboptimal and correlated to age and magnitude of immunosuppression. Administration of a third vaccine dose brings to significant amplification of immune response.

Summary

This review strengthens the existing recommendation of vaccination by three doses of vaccine in all SOT recipients and completion of vaccination before transplantation if possible.

Six-Month Follow-Up after Vaccination with BNT162b2: SARS-CoV-2 Antigen-Specific Cellular and Humoral Immune Responses in Hemodialysis Patients and Kidney Transplant Recipients

Hemodialysis patients (HDP) and kidney transplant recipients (KTR) have a high risk of infection with SARS-CoV-2 with poor clinical outcomes. Because of this, vaccination of these groups of patients against SARS-CoV-2 is particularly important. However, immune responses may be impaired in immunosuppressed and chronically ill patients. Here, our aim was to compare the efficacy of an mRNA-based vaccine in HDP, KTR, and healthy subjects.

DESIGN

In this prospective observational cohort study, the humoral and cellular response of prevalent 192 HDP, 50 KTR, and 28 healthy controls (HC) was assessed 1, 2, and 6 months after the first immunization with the BNT162b2 mRNA vaccine.

RESULTS

After 6 months, 97.5% of HDP, 37.9% of KTR, and 100% of HC had an antibody response. Median antibody levels were 1539.7 (±3355.8), 178.5 (±369.5), and 2657.8 (±2965.8) AU/mL in HDP, KTR, and HC, respectively (p ≤ 0.05). A SARS-CoV-2 antigen-specific cell response to vaccination was found in 68.8% of HDP, 64.5% of KTR, and 90% of HC.

CONCLUSION

The humoral response rates to mRNA-based vaccination of HDPs are comparable to HCs, but antibody titers are lower. Furthermore, HDPs have weaker T-cell response to vaccination than HCs. KTRs have very low humoral and antigen-specific cellular response rates and antibody titers, which requires other vaccination strategies in addition to booster vaccination.