COVID-19 vaccination is protective of clinical disease in solid organ transplant recipients

Repeated COVID-19 Vaccination Drives Memory T- and B-cell Responses in Kidney Transplant Recipients: Results From a Multicenter Randomized Controlled Trial

BACKGROUND

Insight into cellular immune responses to COVID-19 vaccinations is crucial for optimizing booster programs in kidney transplant recipients (KTRs).

METHODS

In an immunologic substudy of a multicenter randomized controlled trial (NCT05030974) investigating different repeated vaccination strategies in KTR who showed poor serological responses after 2 or 3 doses of an messenger RNA (mRNA)-based vaccine, we compared SARS-CoV-2-specific interleukin-21 memory T-cell and B-cell responses by enzyme-linked immunosorbent spot (ELISpot) assays and serum IgG antibody levels. Patients were randomized to receive: a single dose of mRNA-1273 (100 μg, n = 25), a double dose of mRNA-1273 (2 × 100 μg, n = 25), or a single dose of adenovirus type 26 encoding the SARS-CoV-2 spike glycoprotein (Ad26.COV2.S) (n = 25). In parallel, we also examined responses in 50 KTR receiving 100 μg mRNA-1273, randomized to continue (n = 25) or discontinue (n = 25) mycophenolate mofetil/mycophenolic acid. As a reference, the data were compared with KTR who received 2 primary mRNA-1273 vaccinations.

RESULTS

Repeated vaccination increased the seroconversion rate from 21% to 66% in all patients, which was strongly associated with enhanced levels of SARS-CoV-2-specific interleukin-21 memory T cells (odd ratio, 3.84 [1.89-7.78]; P < 0.001) and B cells (odd ratio, 35.93 [6.94-186.04]; P < 0.001). There were no significant differences observed in these responses among various vaccination strategies. In contrast to KTR vaccinated with 2 primary vaccinations, the number of antigen-specific memory B cells demonstrated potential for classifying seroconversion after repeated vaccination (area under the curve, 0.64; 95% confidence interval, 0.37-0.90; P = 0.26 and area under the curve, 0.95; confidence interval, 0.87-0.97; P < 0.0001, respectively).

CONCLUSIONS

Our study emphasizes the importance of virus-specific memory T- and B-cell responses for comprehensive understanding of COVID-19 vaccine efficacy among KTR.

Designing and analyzing studies of coronavirus disease 2019 and post-acute sequelae of severe acute respiratory syndrome coronavirus 2 among immunocompromised individuals

Observational studies of coronavirus disease 2019 (COVID-19) among transplant candidates and recipients remain important as immunocompromised patients formed a very small proportion of patients included in COVID-19 trials and large database analyses. We discuss methods that have been used in such analyses to evaluate the impact of vaccination on the risk of symptomatic COVID-19 in such patients and on the probability of developing post-acute sequelae of severe acute respiratory syndrome coronavirus 2 after the onset of infection. We also propose future directions for research and discuss the methods that will be useful to conduct such investigations. The study design and analytical issues that we consider have the potential to be helpful not only for COVID-19 research but also for other infections as well.

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.

Disease Course, Management and Outcomes in Kidney Transplant Recipients with SARS-CoV-2 Infection during the Omicron-Variant Wave: A Single-Center Experience

Background: Since December 2019, kidney transplant recipients (KTRs) have experienced a great impact of the coronavirus disease 2019 (COVID-19) pandemic, with a higher risk of morbidity and mortality compared to the general population. Preliminary data in KTRs suggest that the Omicron variant, which has been dominant since December 2021, is more infectious than the previous ones but is associated with reduced risk of severity and low lethality rates. The purpose of our study was to assess the disease course and outcomes of the SARS-CoV-2 infection in KTRs during the Omicron-surge. Methods: This retrospective study included 451 KTRs diagnosed with SARS-CoV-2 infection between 1 December 2021 and 30 September 2022. Demographic and clinical characteristics at the time of infection, vaccination data, treatment, clinical course, and outcomes were recorded and analyzed. Results: Mean age was 51.8 ± 13.7 years with a male predominance (61.2%). The majority (76.1%) were vaccinated with at least three doses of the available mRNA vaccines, although serology revealed low anti-SARS-CoV-2 antibody titers before infection (33 [3.3–1205] AU/mL). Only 6% of the patients experienced moderate–severe disease. Accordingly, there was low prevalence of adverse outcomes, such as SARS-CoV-2-related hospitalization (11.3%) and death (0.9%). Multivariate analysis revealed that only age significantly increased the risk of SARS-CoV-2-related hospitalization. Conclusions: During the Omicron wave, the clinical course of the SARS-CoV-2 infection in KTRs has substantially changed, with lower rates of moderate and severe disease and a low prevalence of adverse outcomes. Prospective clinical trials are warranted to further elucidate the evolving pathogenesis, management, and long-term outcomes of COVID-19 in such high-risk populations.

Clinical Effectiveness of SARS-CoV-2 Vaccination in Renal Transplant Recipients. Antibody Levels Impact in Pneumonia and Death

BACKGROUND

Few studies have described the clinical impact of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in renal transplant recipients (RTRs) in the context of omicron variant and the third vaccine dose. Antibody titer has been tried to relate to the prediction of outcomes related to SARS-CoV-2, but it results controversially in these populations.

METHODS

All patients with positive SARS-CoV-2 polymerase chain reaction followed at a RTRs reference center from March 15, 2020, to March 15, 2022, were considered for analysis. Cases were analyzed by vaccination status. Breakthrough cases were then analyzed by nonantibodies (<20 arbitrary unit [AU]/mL), low (20-100 AU/mL), and high antibody titers (>100 AU/mL) against SARS-CoV-2 spike protein. Outcomes included pneumonia and mortality. We used logistic regression multivariable to assess for confounders.

RESULTS

Among 186 RTRs with coronavirus disease 2019, 50.5% (n = 94) were vaccinated versus 49.5% (n = 92) unvaccinated. Of the vaccinated patients, 67.02% developed a high antibody titer (>100 AU/mL) but 14.89% achieved a low antibody titer and 18.08% nonantibodies. Pneumonia-free survival (day 20) was 95% in high antibody titer but 40% in unvaccinated RTRs. Survival in RTRs at day 60 was similar in the unvaccinated group compared with nonantibodies breakthrough cases (82%) but 92% in the low antibody titer group (relative risk, 0.027; 95% confidence interval, 0.002-0.479; P = 0.014). Only patients with >100 AU/mL showed a 100% survival on day 60 postinfection.

CONCLUSIONS

Vaccinated RTRs who achieve at least a low antibody titer (>20 AU/mL) had better results in terms of pneumonia and mortality than unvaccinated RTRs. Antibody titer >100 AU/mL associate with even better results than patients with lower antibody titers.

Outcome of COVID-19 in Kidney Transplant Recipients Through the SARS-CoV-2 Variants Eras: Role of Anti-SARS-CoV-2 Monoclonal Antibodies

Kidney transplant recipients (KTR) are at increased risk for COVID-19-associated complications. We aimed to describe the evolving epidemiology and outcome of PCR-documented SARS-CoV-2 infection in KTR followed at our institution from March 2020 to May 2022. The primary endpoint was hospitalization for COVID-19-related symptoms or death within 28 days from diagnosis. Overall, 243 cases were included of which 68 (28%) developed the primary outcome. A significant decrease in the incidence of the primary outcome was observed (p &lt; 0.001, r −0.342) during the study period. Anti-Spike monoclonal antibodies (mAbs) were administered as early treatment (within 5–7 days of onset of symptoms) in 101 patients (14 with casirivimab/imdevimab and 87 with sotrovimab). Among 145 patients who had received at least one vaccination dose before infection, 109 patients were considered as adequately vaccinated. Multivariate analysis revealed that the Charlson Comorbidity Index (P 0.001; OR 1.28, CI 1.11–1.48) was associated with the primary outcome, while early administration of mAbs (P 0.032; OR 0.39, CI 0.16–0.92) was associated with a better outcome, but not infection during the period of the omicron variant predominance or adequate vaccination.

Temporary reduction of immunosuppression enhances production of anti-S antibody against severe acute respiratory syndrome coronavirus 2 after vaccination in kidney transplant recipients

OBJECTIVES

The study identified factors affecting anti-S immunoglobulin G production after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in kidney transplant recipients.

METHODS

Serum samples were prospectively collected from kidney transplant recipients, live kidney donors, and healthy volunteers 1 month after receiving the second dose of SARS-CoV-2 vaccine, and anti-S immunoglobulin G titers were measured. The mycophenolate mofetil dose was reduced before vaccination in some immunologically low-risk recipients.

RESULTS

A total of 151 kidney transplant recipients, 74 live kidney donors, and 50 healthy volunteers were included. Kidney transplant recipients had significantly lower titers of anti-S immunoglobulin G than donors and healthy volunteers (1377 ± 246, 8310 ± 932, and 9908 ± 1040 AU/ml, respectively). Only 67.3% of kidney transplant recipients, compared to 100% of donors and healthy volunteers, were positive for anti-S immunoglobulin G. Among the kidney transplant recipients, the anti-S titer was higher in younger recipients, those with higher peripheral blood lymphocyte counts and glomerular filtration rates, those without a history of antithymocyte globulin use, and those who had discontinued or received a reduced dose of mycophenolate mofetil. Younger age, higher lymphocyte count, glomerular filtration rate, and mycophenolate reduction were significantly associated with anti-S immunoglobulin G > 1000 AU/ml in nominal logistic regression analysis. There were no rejection episodes after mycophenolate modification in kidney transplant recipients.

CONCLUSIONS

Anti-S immunoglobulin G production after vaccination was attenuated in kidney transplant recipients. Mycophenolate mofetil cessation or reduction is a modifiable means to enhance anti-S immunoglobulin G production in immunosuppressed kidney transplant recipients.

SARS-CoV-2 Vaccination in Solid-Organ Transplant Recipients

The coronavirus disease 2019 (COVID-19) pandemic has posed significant global challenges for solid organ transplant (SOT) recipients. Mortality rates of COVID-19 in this patient population remain high, despite new available therapeutic options and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination. Priority access to SARS-CoV-2 vaccination for waitlisted candidates and for SOT patients and their family members is recommended since the advantage from vaccination reduces the risk of COVID-19-related complications. However, immunogenicity and efficacy of COVID-19 vaccines are lower in waitlisted candidates and SOT recipients than in the general population. Routine systematic assessment of humoral and cellular immune responses after SARS-CoV-2 vaccination is controversial, although highly recommended for investigation and improvement of knowledge. SOT recipients should continue to adhere to preventive protective measures despite vaccination and may undergo passive antibody prophylaxis. This article seeks to provide an update on SARS-CoV-2 vaccination and preventive measures in SOT recipients based on existing literature and international guidelines.

Evaluating clinical effectiveness of SARS-CoV-2 vaccine in solid organ transplant recipients: A propensity score matched analysis

BACKGROUND

Solid organ transplant recipients (SOTRs) are at disproportionate risk for severe Coronavirus Disease 2019 (COVID-19). Vaccination is a key preventative strategy but is associated with decreased humoral responses among SOTR. Whether dampened immune responses correlate with reduced clinical effectiveness is unclear. Our study was designed to evaluate the clinical effectiveness of SARS-CoV-2 vaccination in the early vaccine era.

METHODS

We conducted a retrospective cohort study comparing SARS-CoV-2 infection rates between SOTRs who received two doses of mRNA or one dose of Ad26.Cov2.S vaccine and those not fully vaccinated (partially vaccinated and unvaccinated). To evaluate clinical effectiveness of vaccine, cause-specific Cox regression model and modified Poisson regression model were built using the propensity score-matched cohort. Additionally, the clinical outcomes of COVID-19 of fully vaccinated and not fully vaccinated SOTR were compared.

RESULTS

Of 2705 SOTRs, 1668 were included in our final matched analysis, which showed a 73% reduction of SARS-CoV-2 infection and 76% reduction of all-cause-mortality among fully vaccinated patients. Thirty-nine SOTRs developed SARS-CoV-2 infection, including nine fully vaccinated and 30 not fully vaccinated. Among fully vaccinated patients, 22% had severe/critical COVID-19 and 0% mortality versus not fully vaccinated SOTRs, of whom 37% had severe/critical COVID-19 and 6.67% COVID-19-related mortality.

CONCLUSION

In SOTRs, completion of primary vaccine series in the early vaccine era was associated with a significant reduction of COVID-19 and was protective against severe/critical disease and death. Further studies are needed to evaluate the clinical effectiveness of current vaccine recommendations for SOTR against emerging new variants.

Evolution of Clinical Care in COVID-Infected Solid Organ Transplant Recipients

Purpose of Review

In this review, we aim to summarize the evolution of care for the solid organ transplant recipient (SOTR) with COVID-19 disease, based on the current published guidelines and our center’s experience.

Recent Findings

Oral antiviral medications and monoclonal antibodies are now used with the goal to prevent severe disease. Immunomodulating drugs in addition to antivirals have been used in the treatment of severe COVID-19.

Summary

With the ongoing pandemic and unique challenges posed by the SOTR, understanding the risk and advancing management and treatment of COVID-19 infections are imperative to the successful care of a transplant recipient. There are many ongoing clinical trials being conducted in hopes of developing novel therapeutics towards COVID-19.

Breakthrough COVID-19 Infections in the US: Implications for Prolonging the Pandemic

The incidence of COVID-19 breakthrough infections-an infection that occurs after you have been vaccinated-has increased in frequency since the Delta and now Omicron variants of the SARS-CoV-2 coronavirus have become the dominant strains transmitted in the United States (US). Evidence suggests that individuals with breakthrough infections, though rare and expected, may readily transmit COVID-19 to unvaccinated populations, posing a continuing threat to the unvaccinated. Here, we examine factors contributing to breakthrough infections including a poor immune response to the vaccines due to the fact of advanced age and underlying comorbidities, the natural waning of immune protection from the vaccines over time, and viral variants that escape existing immune protection from the vaccines. The rise in breakthrough infections in the US and how they contribute to new infections, specifically among the unvaccinated and individuals with compromised immune systems, will create the need for additional booster vaccinations or development of modified vaccines that directly target current variants circulating among the general population. The need to expedite vaccination among the more than 49.8 million unvaccinated eligible people in the US is critical.

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

Purpose of Review

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

Recent Findings

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

Summary

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

Serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine in lung transplant recipients

Lung transplant recipients have an increased risk for severe coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A third dose of a SARS-CoV-2 vaccine has been recommended for all solid organ transplant recipients, but data from lung transplant recipients specifically are scarce. In this study, the serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine was measured in 78 lung transplant recipients. Sixty-two percent (n = 48) had a serological response to vaccination, which was significantly higher than after the second vaccine dose (27 patients (35%); p = 0.0013). A positive serologic response was associated with having had COVID-19 (p = 0.01), and higher serum IgG level and complement mannose binding lectin pathway activity prior to vaccination (p = 0.04 and p = 0.03, respectively). Serologic response was not associated with the dose of mycophenolate mofetil or prednisone or other immune status parameters. Eleven patients (14%) developed COVID-19 after the second or third vaccine dose, but this did not associate with serologic response after the second vaccine dose (9% in patients who developed COVID-19 versus 39% in patients who did not develop COVID-19 (p = 0.09)), or with serologic response above cut-off values associated with clinical protection in previous studies. In conclusion, the response to mRNA-based SARS-CoV-2 vaccines in lung transplant recipients improves significantly after a third vaccine dose. Factors associated with a positive serologic response are having had COVID-19 prior to vaccination, and serum IgG and complement mannose binding lectin pathway activity prior to vaccination. Serologic response did not associate with clinical protection against COVID-19 in this study.