Update on Coronavirus 2019 Vaccine Guidelines for Transplant Recipients

Immunogenicity and Predictive Factors Associated with Poor Response after Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination in Lung Transplant Patients

Lung transplant patients are more likely to develop severe coronavirus disease 2019 (COVID-19) compared with the general population and should be vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, previous studies have reported reduced vaccination immunogenicity in lung transplantation patients. We aimed to investigate the serological response and associated factors after SARS-CoV-2 vaccination in this population. Lung transplant patients without a history of contracting coronavirus disease who had received a second or higher dose of SARS-CoV-2 vaccination were enrolled. The anti-SARS-Cov-2 spike and neutralizing antibody levels were measured in blood samples. Firth's logistic regression analysis was performed to assess the factors associated with non-response after vaccination. Forty-six lung transplant patients were enrolled, of which sixteen (34.8%) showed a serological response to vaccination. All patients who received anti-SARS-CoV-2 vaccination before transplantation (n = 5) exhibited a serological response. No significant difference was observed in anti-SARS-CoV-2 S antibody or neutralization titers based on the number and timing of vaccination. Firth's logistic regression showed an association between lower hemoglobin levels (odds ratio, 0.59; confidence interval, 0.35-0.92; p = 0.017) and non-response to SARS-CoV-2 vaccination. Lung transplant patients showed poor serologic responses after SARS-CoV-2 vaccination in this pilot study; anemia may be associated with this poor response.

Pretransplantation coronavirus disease 2019 vaccination requirements: A matched case-control study of factors associated with waitlist inactivation

Numerous United States transplant centers require solid organ transplantation candidates to be vaccinated against the coronavirus disease of 2019 to be active on the United Network for Organ Sharing waiting list. This study examined characteristics of adult patients on one center's kidney transplantation waiting list whose status was inactivated due to a lack of coronavirus disease 2019 vaccination by July 1, 2022, and who did not subsequently provide proof of vaccination by August 31, 2022 (cases). Patients in the control group were retrospectively matched to patients in the case group in a 4-to-1 fashion according to age, sex, and "active" status on the waiting list. Multivariable logistic regression was performed, with race/ethnicity, primary language, health insurance, education, and Vaccine Equity Metric (VEM, a measure of health equity at the zip code level) quartile as covariates. Results revealed that patients from zip codes in the lowest VEM quartile (odds ratio [OR] 1.89; P = .02) and those insured by governmental payors (Medicare: OR, 2.00; P < .01 and Medicaid: OR, 2.89; P < .01) had higher odds of being inactivated than those from zip codes that make up the highest VEM quartile and those insured by commercial payors, respectively. These findings serve as a cautionary tale regarding universal pretransplantation vaccination requirements, which may raise equity concerns that should be considered upon policy implementation.

Antibody response to ChAdOx1 nCoV-19 (Covishield®) vaccine in people on maintenance hemodialysis

INTRODUCTION

People on renal replacement therapy (RRT) have a high risk of COVID-19 infection and subsequent death. COVID-19 vaccination is strongly recommended for those on RRT. Data are limited on the immune response of the ChAdOx1 nCoV-19/AZD1222 (Covishield®) vaccine in patients on RRT.

METHODS

A prospective cohort of adult (age > 18 years), on RRT in the form of hemodialysis were included and received two intramuscular doses of Covishield®. A blood specimen of 5.0 mL was collected at two time points, within a few days before administering the first dose of the vaccine and at 4-16 weeks after the second dose. According to their prior COVID-19 infection status, the participants were grouped as (i) prior symptomatic COVID-19 infection, (ii) prior asymptomatic COVID-19 infection, and (iii) no prior COVID-19 infection.

RESULTS

A large proportion (81%) of participants had anti-spike antibodies (ASAb) before vaccination, and a reasonable proportion (30%) also had neutralizing antibodies (NAb). The titer of ASAb was relatively low (207 U/mL) before vaccination. The ASAb titer (9405 [1635-25,000] U/mL) and percentage of NAb (96.4% [59.6-98.1%]) were markedly increased following the administration of two doses of the vaccine. The participants' prior COVID-19 exposure status did not influence the rise in ASAb titer and NAb percentage. Further, administering two doses of the Covishield vaccine helps them achieve a high ASAb titer.

CONCLUSION

Two doses of ChAdOx1 nCoV-19/AZD1222 (Covishield®) vaccine, given 12 weeks apart, achieve a high titer of ASAb and a high percentage of NAb in people on hemodialysis.

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.

Immunogenicity of Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV; Sinopharm) and Short-Term Clinical Outcomes in Vaccinated Solid Organ Transplant Recipients: A Prospective Cohort Study

BackgroundImmunocompromised patients have lower seroconversion rate in response to COVID-19 vaccination. The aim of this study is to evaluate the humoral immune response with short-term clinical outcomes in solid organ transplant recipients vaccinated with SARS-CoV-2 vaccine (BBIBP-CorV; Sinopharm).MethodsThis prospective cohort was conducted from March to December 2021 in Abu Ali Sina hospital, Iran. All transplant recipients, older than 18 years were recruited. The patients received two doses of Sinopharm vaccine 4 weeks apart. Immunogenicity was evaluated through assessment of antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 after the first and second dose of vaccine. The patients were followed up for 6 months after vaccination.ResultsOut of 921 transplant patients, 115 (12.5%) and 239 (26%) had acceptable anti S-RBD immunoglobulin G (IgG) levels after the first and second dose, respectively. Eighty patients (8.68%) got infected with COVID-19 which led to 45 (4.9%) of patients being hospitalized. None of the patients died during follow-up period. Twenty-four (10.9%) liver transplant recipients developed liver enzyme elevation, and increased serum creatinine was observed in 86 (13.5%) kidney transplant patients. Two patients experienced biopsy-proven rejection without any graft loss.ConclusionOur study revealed that humoral response rate of solid organ transplant recipients to Sinopharm vaccine was low.

Humoral immune response following a third SARS-CoV-2 mRNA vaccine dose in solid organ transplant recipients compared with matched controls

Background

Solid organ transplant (SOT) recipients have shown suboptimal antibody response following COVID-19 vaccination. Several risk factors for the diminished response have been identified including immunosuppression and older age, but the influence of different comorbidities is not fully elucidated.

Method

This case-control study consisted of 420 Danish adult SOT recipients and 840 sex- and age-matched controls, all vaccinated with a third homologous dose of either BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine. The primary outcome was differences in humoral immune response. The secondary outcome was breakthrough infections. Additionally, we looked for factors that could predict possible differences between the two groups.

Results

Response rate increased from 186/382 (49%) to 275/358 (77%) in SOT recipients and remained on 781/790 (99%) to 601/609 (99%) in controls following a third vaccine dose. SOT recipients had significantly lower median antibody concentrations after third dose compared to controls (332.6 BAU/ml vs 46,470.0 BAU/ml, p <0.001). Lowest median antibody concentrations were seen in SOT recipients with liver disease (10.3 BAU/ml, IQR 7.1-319) and diabetes (275.3 BAU/ml, IQR 7.3-957.4). Breakthrough infections occurred similarly frequent, 150 (40%) among cases and 301 (39%) among controls (p = 0.80).

Conclusion

A third COVID-19 vaccine dose resulted in a significant increase in humoral immunogenicity in SOT recipients and maintained high response rate in controls. Furthermore, SOT recipients were less likely to produce antibodies with overall lower antibody concentrations and humoral immunity was highly influenced by the presence of liver disease and diabetes. The prevalence of breakthrough infections was similar in the two groups.

Antibody Response to ChAdOx1 nCoV-19 (AZD1222) Vaccine in Kidney Transplant Recipients

Kidney transplant recipients (KTRs) are at a much higher risk of complications and death following COVID-19 and are poor vaccine responders. The data are limited on the immune response to Covishield® in KTRs. We prospectively recruited a cohort of 67 KTRs aged >18 between April 2021 and December 2021. Each participant was given two intramuscular doses of Covishield®, each of 0.5 mL, at an interval of 12 weeks. A blood specimen of 5.0 mL was collected from each participant at two points within a few days before administering the first dose of the vaccine and at any time between 4−12 weeks after administering the second dose. The sera were tested for anti-RBD antibody (ARAb) titre and neutralising antibody (NAb). An ACE2 competition assay was used as a proxy for virus neutralization. According to the prior COVID-19 infection, participants were grouped as (i) group A: prior symptomatic COVID-19 infection, (ii) group B: prior asymptomatic COVID-19 infection as evidenced by detectable ARAb in the prevaccination specimen, (iii) Group C: no prior infection with COVID-19, (iv) group D: Unclassified, i.e., participants had no symptoms suggestive of COVID-19, but their prevaccination specimen was not available for ARAb testing before vaccination. Fifty of sixty-seven participants (74.6%) provided paired specimens (group A 14, group B 27, and group C 9) and 17 participants (25.4%) provided only postvaccination specimens (group D). In the overall cohort (n = 67), 91% and 77.6% of participants developed ARAb and NAb, respectively. Their ARAb titre and NAb proportion were 2927 (520−7124) U/mL and 87.9 (24.4−93.2) %, respectively. Their median ARAb titre increased 65.6 folds, from 38.2 U/mL to 3137 U/mL. Similarly, the proportion of participants with NAb increased from 56% to 86%, and the NAb proportion raised 2.7 folds, from 23% to 91%. A comparison of vaccine response between the study groups showed that all those with or without prior COVID-19 infection showed a significant rise in ARAb titre (p < 0.05) and NAb proportion (p < 0.05) after the two doses of vaccine administration. The median value of folds rise in anti-RBD and NAb between groups A and B were comparable. Hence, ARAb is present in more than 3/4th of KTRs before the ChAdOx1 vaccine in India. The titer of ARAb and the proportion of NAb significantly increased after the two doses of the ChAdOx1 vaccine in KTRs.

COVID-19 Pandemic Research Opportunities in India: What the Pandemic Is Teaching Us About Transplantation

Coronavirus disease (COVID-19) has engulfed the whole world, and India has been the second worst-hit nation. Organ transplant services were halted in both the public and private care sectors of India, with public care sectors more adversely affected. Deceased donations were disproportionately more affected, with unfavorable rates at the peak of the pandemic. Mortality outcomes of COVID-19 among different organ transplant recipients in India have been lower compared with the Western world, with younger age and less comorbidities among Indian populations partly responsible for the lower mortality. Mortality and graft loss were mostly associated with older age and those with chronic graft dysfunction. During the pandemic, invasive fungal infections, like mucormycosis, have been reported, illustrating the need for multidisciplinary management. The Indian transplant societies have formulated and timely revised guidelines for transplantation in the COVID-19 era. Living donor transplants (both liver and kidney) after recovery from COVID-19 were both first described in India, providing a guiding tool for the world. Follow-up reports of recovered solid-organ transplant recipients have also been reported in Indian studies, showing reassuring long-term outcomes. Data of breakthrough COVID-19 cases after vaccination among both transplant recipients and waitlist candidates and research in vaccine efficacy for solid-organ transplant recipients is still underway. We suggest continuing and intensifying research activities for a better plan and strategy in case of a future pandemic.

Determinants of Antibody Response to a Third SARS-CoV-2 mRNA Vaccine Dose in Solid Organ Transplant Recipients: Results from the Prospective Cohort Study COVAC-Tx

Background: We studied factors related to humoral response in solid organ transplant (SOT) recipients following a three-dose regimen of an mRNA-based SARS-CoV-2 vaccine. Method: This was a prospective study of SOT recipients who received a third homologous dose of the BNT162b2 (Pfizer–BioNTech) vaccine. The anti-spike S1 IgG response was measured using the SARS-CoV-2 IgG II Quant assay (Abbott Laboratories) with a cut-off of 7.1 BAU/mL. Multiple logistic regression was used to determine the factors associated with humoral response. Results: In total, 395 SOT recipients were included. Anti-spike IgG was detected in 195/395 (49.4%) patients after the second dose and 261/335 (77.9%) patients after the third dose. The overall mean increase in antibody concentration after the third dose was 831.0 BAU/mL (95% confidence interval (CI) 687.4–974.5) and 159 (47.5%) participants had at least a 10-fold increase in antibody concentration after the third dose. The increase in antibody concentration was significantly higher among patients with detectable antibodies after the second dose than those without. Cumulative time from transplantation and liver recipients was positively associated with an antibody response, whereas older age, administration of prednisolone, and proliferation inhibitors were associated with diminished antibody response. Conclusion: Although the third dose of the BNT162b2 vaccine improved humoral responses among SOT non-responders following the second dose, the overall response remained low, and 22.1% did not develop any response. Patients at risk of a diminished vaccine response require repeated booster doses and alternative treatment approaches.