Efficacy and safety of booster vaccination against SARS-CoV-2 in dialysis and renal transplant patients: systematic review and meta-analysis

B and T cell responses to the 3rd and 4th dose of the BNT162b2 vaccine in dialysis patients

Patients on dialysis (PoD) are at high risk of severe morbidity and mortality from COVID-19. Characterizing long-term vaccine immune responses in these patients will help optimize vaccine schedule for PoD. This study aimed to determine whether long-term humoral and B and T cell-responses post 3rd and 4th dose of the BNT162b2 vaccine differed between PoD and controls. Non-infected PoD and controls vaccinated with BNT162b2 were recruited in Ziv Medical Center, Israel, between 2021 and 2022. Specimens were collected 1-2 months pre 3rd dose; 1-3 months post 3rd dose; 4-5 months post 3rd dose and 3-5 months post the 4th dose. Anti-SARS-CoV-2 spike (spike) specific antibodies, spike specific memory B cells, and spike specific CD154+ T cells as well as cytokines producing CD4+/CD8+ T cells were measured using standardized assays and compared between PoD and controls at each time point using Mann Whitney and Fisher's exact tests. We recruited 22 PoD and 20 controls. Antibody levels in PoD were lower compared to controls pre 3rd dose but not post 3rd and 4th doses. Frequencies of spike specific memory B cell populations were similar between PoD and controls overall. Frequencies of spike specific T cells, including those producing IFNγ and TNFα, were not lower in PoD. B and T cell mediated immune response in PoD following a 3rd and a 4th dose of the BNT162b2 vaccine was not inferior to controls up to 5 months post vaccination. Our results suggest that standard BNT162b2 vaccination is suitable for this group.

COVID-19 Vaccination Recommendations for Immunocompromised Patient Populations: Delphi Panel and Consensus Statement Generation in the United States

INTRODUCTION

The United States Advisory Committee on Immunization Practices (ACIP) and the Centers for Disease Control (CDC) recommend COVID-19 vaccines for all immunocompromised individuals. Certain disease groups are at increased risk of comorbidity and death for which disease-specific recommendations should be considered. The objective of the Delphi panel of experts was to summarize expert consensus on COVID-19 vaccinations for patients with rheumatologic disease, renal disease, hematologic malignancy and solid organ transplant (SOT) in the US.

METHODS

A two-stage Delphi panel method was employed, starting with qualitative interviews with key opinion leaders (KOLs) in the four disease areas (n = 4 KOLs, n = 16 total) followed by three rounds of iterative revision of disease-specific COVID-19 vaccine recommendations. Final consensus was rated after the third round. Statements addressed primary and booster dosing (e.g., number and frequency) and other considerations such as vaccine type or heterologous messenger ribonucleic acid (mRNA) vaccination. Following the Delphi Panel, an online survey was conducted to assess physician agreement within the disease areas (n = 50 each, n = 200 total) with the consensus statements.

RESULTS

Moderate to strong consensus was achieved for all primary series vaccination statements across disease groups, except one in hematology. Similarly, moderate to strong consensus was achieved for all booster series statements in all disease areas. However, statements on antibody titer measurements for re-vaccination considerations and higher dosages for immunocompromised patients did not reach agreement. Overall, approximately 62%-96% of physicians strongly agreed with the primary and booster vaccine recommendations. However, low agreement (29%-69%) was found among physicians for time interval between disease-specific treatment and vaccination, recommendations for mRNA vaccines, heterologous mRNA vaccination, antibody titer measurement and higher vaccine dosage for immunocompromised groups.

CONCLUSION

Consensus was achieved for disease-specific COVID-19 vaccine recommendations concerning primary and booster series vaccines and was generally well accepted by practicing physicians.

Delphi Panel Consensus Statement Generation: COVID-19 Vaccination Recommendations for Immunocompromised Populations in the European Union

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented pressure on healthcare systems globally. The lack of quality guidelines on the management of COVID-19 in rheumatologic disease, renal disease, hematological malignancy, and solid organ transplant recipients has resulted in a wide variation in clinical practice.

METHODS

Using a Delphi process, a panel of 16 key opinion leaders developed clinical practice statements regarding vaccine recommendations in areas where standards are absent or limited. Agreement among practicing physicians with consensus statements was also assessed via an online physician survey. The strength of the consensus was determined by the following rating system: a strong rating was defined as all four key opinion leaders (KOLs) rating the statement ≥ 8, a moderate rating was defined as three out of four KOLs rating the statement ≥ 8, and no consensus was defined as less than three out of four KOLs provided a rating of ≤ 8. Specialists voted on agreement with each consensus statement for their disease area using the same ten-point scoring system.

RESULTS

Key opinion leaders in rheumatology, nephrology, and hematology achieved consensuses for all nine statements pertaining to the primary and booster series with transplant physicians reaching consensus on eight of nine statements. Experts agreed that COVID-19 vaccines are safe, effective, and well tolerated by patients with rheumatological conditions, renal disease, hematologic malignancy, and recipients of solid organ transplants. The Delphi process yielded strong to moderate suggestions for the use of COVID-19 messenger ribonucleic acid (mRNA) vaccines and the necessity of the COVID-19 booster for the immunocompromised population. The expert panel had mixed feelings concerning the measurement of antibody titers, higher-dose mRNA vaccines, and the development of disease-specific COVID-19 guidance.

CONCLUSIONS

These results confirmed the necessity of COVID-19 vaccines and boosters in immunocompromised patients with rheumatologic disease, renal disease, hematological malignancy, and solid organ transplant recipients. Statements where consensus was not achieved were due to absent or limited evidence.

Impact of Anti-SARS-CoV-2 Vaccination on Disease Severity and Clinical Outcomes of Individuals Hospitalized for COVID-19 Throughout Successive Pandemic Waves: Data from an Italian Reference Hospital

This is a retrospective observational study including all COVID-19 patients admitted at our Institute throughout three successive pandemic waves, from January 2021 to June 2023. The main in-hospital outcomes (clinical progression [CP], defined as admission to Intensive Care Unit [ICU]/death, and death within 28 days) were compared among participants unvaccinated (NV), fully vaccinated (FV), with one (FV&B1) and two (FV&B2) booster doses. Vaccinated participants were stratified into recently and waned FV/FV&B1/FV&B2, depending on the time elapsed from last dose (≤ and >120 days, respectively). There were 4488 participants: 2224 NV, 674 FV, 1207 FV&B1, and 383 FV&B2. Within 28 days, there were 604 ICU admissions, 396 deaths, and 737 CP. After adjusting for the main confounders, the risk of both in-hospital outcomes was reduced in vaccinated individuals, especially in those who received the booster dose (approximately by 36% for FV and >50% for FV&B1 and FV&B2 compared to NV). Similarly, after restricting the analysis to vaccinated participants only, we observed a risk reduction of approximately 40% for FV&B1 and 50% for FV&B2, compared to FV, regardless of the distance since the last dose. Our data confirm the vaccine's effectiveness in preventing severe COVID-19 and support the efforts to increase the uptake of booster doses, mainly among older and frailer individuals, still at a greater risk of clinical progression.

Therapeutic Myths in Solid Organ Transplantation Infectious Diseases

Infection management in solid organ transplantation poses unique challenges, with a diverse array of potential pathogens and associated antimicrobial therapies. With limited high-quality randomized clinical trials to direct optimal care, therapeutic "myths" may propagate and contribute to suboptimal or excessive antimicrobial use. We discuss 6 therapeutic myths with particular relevance to solid organ transplantation and provide recommendations for infectious diseases clinicians involved in the care of this high-risk population.

Immunologic responses to the third and fourth doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in cell therapy recipients: a systematic review and meta-analysis

BACKGROUND

Multiple studies have provided evidence of suboptimal or poor immune responses to SARS-CoV-2 vaccines in recipients of hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cell therapy compared to healthy individuals. Given the dynamic nature of SARS-CoV2, characterized by the emergence of many viral variations throughout the general population, there is ongoing discussion regarding the optimal quantity and frequency of additional doses required to sustain protection against SARS-CoV2 especially in this susceptible population. This systematic review and meta-analysis investigated the immune responses of HSCT and CAR-T cell therapy recipients to additional doses of the SARS-CoV-2 vaccines.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the study involved a comprehensive search across PubMed, Scopus, Web of Science Core Collection, Embase, and Cochrane Biorxiv and medRxiv, focusing on the serological responses to the third and fourth vaccine doses in HSCT and CAR-T cell patients.

RESULTS

This study included 32 papers, with 31 qualifying for the meta-analysis. Results showed that after the third dose, the seroconversion rate in HSCT and CAR-T cell therapy recipients who didn't respond to the second dose was 46.10 and 17.26%, respectively. Following the fourth dose, HSCT patients had a seroconversion rate of 27.23%. Moreover, post-third-dose seropositivity rates were 87.14% for HSCT and 32.96% for CAR-T cell therapy recipients. Additionally, the seropositive response to the fourth dose in the HSCT group was 90.04%.

CONCLUSION

While a significant portion of HSCT recipients developed antibodies after additional vaccinations, only a minority of CAR-T cell therapy patients showed a similar response. This suggests that alternative vaccination strategies are needed to protect these vulnerable groups effectively. Moreover, few studies have reported cellular responses to additional SARS-CoV-2 vaccinations in these patients. Further studies evaluating cellular responses are required to determine a more precise assessment of immunogenicity strength against SARS-CoV-2 after additional doses.

Humoral response to SARS-CoV-2 mRNA vaccine on in ABO blood type incompatible kidney transplant recipients treated with low-dose rituximab

We aimed to evaluate the humoral response after the second and third doses of SARS-CoV-2 mRNA vaccine in ABO blood type incompatible kidney transplant (KT) recipients treated with rituximab. This retrospective study conducted between June 2021 and June 2022 included 131 KT recipients and 154 nontransplant controls who had received mRNA vaccines. We compared the seropositivity (anti-SARS-CoV-2 spike IgG antibody titer ≥ 0.8 U/mL) after the second and third vaccinations. Furthermore, we evaluated the impact of pretransplant vaccination for seropositivity. Of the 131 KT recipients, 50 had received the third dose of mRNA vaccine. The antibody titer was significantly increased after the third dose of mRNA vaccine. The seropositivity rate after the third dose of mRNA vaccine increased from 36 to 70%. We observed no significant difference in seropositivity after the third dose of mRNA vaccine in ABO incompatibility, rituximab use, mycophenolate mofetil use, and age at KT. Of the nine recipients who had received the second or third dose of the mRNA vaccine prior to the KT, eight of the recipients were seropositive both before and after the KT. Our results suggest that ABO incompatibility or rituximab use was not significantly associated with seropositivity.

COVID-19 vaccine in hemodialysis patients: Time for a boost

OBJECTIVES

To evaluate anti-spike immunoglobulin G (IgG) antibody levels of hemodialysis patients and correlate them with the patients' demographic data and to evaluate these patients' need for a coronavirus disease-19 (COVID-19) vaccine booster.

METHODS

A cross-sectional multi-center study carried out at King Abdulaziz Kidney Center, Hasan Tahir Hemodialysis Center, and Hayat Organization Hemodialysis Center in Al-Madinah Al-Munawarah, Saudi Arabia. Patients (n=167) who received a minimum single dose of COVID-19 vaccine were recruited. The samples were collected between March 2022 and January 2023. Anti-spike IgG antibody levels were measured using enzyme-linked immunosorbent assays.

RESULTS

A significantly higher proportion of patients who received 3 doses of COVID-19 vaccine had positive serostatus compared with patients who received one or 2 doses (3 doses: 87.2%, one dose: 0.0%, 2 doses: 77.3%; p=0.000). Compared with patients who received one dose, significantly higher IgG antibody levels were detected in patients who received 2 (p=0.013) and 3 doses (p=0.025; n=35). In contrast, there was no significant difference in IgG antibody levels between patients who received 2 or 3 doses (p=0.45). Significant IgG antibody levels were detected in patients who received 2 and 3 doses (p=0.0125) compared with those received one vaccine dose (p=0.0004). Furthermore, patients who received 3 doses had significantly higher IgG antibody levels than patients who received 2 doses (p=0.000).

CONCLUSION

The results show a dose-dependent association between IgG antibody levels and the number COVID-19 vaccines received. The study highlights the need for booster COVID-19 vaccination for patients on hemodialysis.